Content      ..      1       2         ..

Siemens simatic S7-1200. Manual (2015) - page 1

Preface

Welcome to the world of S7-1200. The SIMATIC S7-1200 compact controller is the modular,

space-saving controller for small automation systems that require either simple or advanced

functionality for logic, HMI and networking. The compact design, low cost, and powerful

features make the S7-1200 a perfect solution for controlling small applications.

As part of the SIMATIC commitment to "totally integrated automation" (TIA), the S7-1200

product family and the TIA Portal programming software give you the flexibility you need to

solve your automation needs.

The S7-1200 helps to make the most challenging tasks easy!

The SIMATIC S7-1200 controller solution, designed for the "compact" controller class, is

comprised of the SIMATIC S7-1200 controller and SIMATIC HMI Basic panels that can both

be programmed with the TIA Portal engineering software. The ability to program both

devices using the same engineering software significantly reduces development costs. The

TIA Portal includes STEP 7 for S7-1200 programming and WinCC for designing Basic panel

projects.

The S7-1200 compact controller includes:

• Built-in PROFINET

• High-speed I/O capable of motion control, onboard

analog inputs to minimize space requirements and

the need for additional I/O, 4 pulse generators for

pulse-train and pulse-width applications (Page 70),

and up to 6 high-speed counters (Page 129)

• On-board I/O points built into the CPU modules

provide from 6 to 14 input points and from 4 to 10

output points.

Signal modules for DC, relay, or analog I/O

expand the number of I/O points, and inno-

vative signal boards snap onto the front of

the CPU to provide additional I/O (Page 18).

The SIMATIC HMI Basic panels (Page 20)

were designed specifically for the S7-1200.

This Easy Book provides an introduction to

the S7-1200 PLC. The following pages offer

an overview of the many features and capa-

bilities of the devices.

For additional information, refer to the S7-1200 Programmable Controller System Manual.

For information about UL and FM certification, CE labeling, C-Tick and other standards, refer

to the Technical specifications (Page 361).

3

Introducing the powerful and flexible S7-1200

1

1.1

Introducing the S7-1200 PLC

The S7-1200 controller provides the flexibility and power to control a wide variety of devices

in support of your automation needs. The compact design, flexible configuration, and

powerful instruction set combine to make the S7-1200 a perfect solution for controlling a

wide variety of applications.

The CPU combines a microprocessor, an integrated power supply, input and output circuits,

built-in PROFINET, high-speed motion control I/O, and on-board analog inputs in a compact

housing to create a powerful controller. After you download your program, the CPU contains

the logic required to monitor and control the devices in your application. The CPU monitors

the inputs and changes the outputs according to the logic of your user program, which can

include Boolean logic, counting, timing, complex math operations, and communications with

other intelligent devices.

The CPU provides a PROFINET port for communication over a PROFINET network.

Additional modules are available for communicating over PROFIBUS, GPRS, RS485,

RS232, IEC, DNP3, and WDC networks.

① Power connector

② Memory card slot under top

door

③ Removable user wiring con-

nectors (behind the doors)

④ Status LEDs for the on-

board I/O

⑤ PROFINET connector (on

the bottom of the CPU)

Several security features help protect access to both the CPU and the control program:

● Every CPU provides password protection (Page 87) that allows you to configure access

to the CPU functions.

● You can use "know-how protection" (Page 89) to hide the code within a specific block.

● You can use copy protection (Page 90) to bind your program to a specific memory card or

CPU.

15

Introducing the powerful and flexible S7-1200

1.1 Introducing the S7-1200 PLC

Table 1- 1

Comparing the CPU models

Feature

CPU 1211C

CPU 1212C

CPU 1214C

CPU 1215C

CPU 1217C

Physical size (mm)

90 x 100 x 75

110 x 100 x 75

130 x 100 x 75

150 x 100 x 75

User memory

Work

50 Kbytes

75 Kbytes

100 Kbytes

125 Kbytes

150 Kbytes

Load

1 Mbyte

4 Mbytes

Retentive

10 Kbytes

Local on-board I/O

Digital

6 inputs/4 out-

8 inputs/6 out-

14 inputs/10 output

puts

puts

Analog

2 inputs

2 inputs/2 output

Process image size

Inputs (I)

1024 bytes

Outputs (Q)

1024 bytes

Bit memory (M)

4096 bytes

8192 bytes

Signal module (SM) expansion

None

2

8

Signal board (SB), Battery board

1

(BB), or communication board

(CB)

Communication module (CM)

3

(left-side expansion)

High-speed coun-

Total

Up to 6 configured to use any built-in or SB inputs

ters

1 MHz

-

Ib.2 to Ib.5

100/¹80

Ia.0 to Ia.5

kHz

30/¹20 kHz

--

Ia.6 to Ia.7

Ia.6 to Ib.5

Ia.6 to Ib.1

200 kHz³

Pulse outputs²

Total

Up to 4 configured to use any built-in or SB outputs

1 MHz

--

Qa.0 to Qa.3

100 kHz

Qa.0 to Qa.3

Qa.4 to Qb.1

20 kHz

--

Qa.4 to Qa.5

Qa.4 to Qb.

--

Memory card

SIMATIC Memory card (optional)

Real time clock retention time

20 days, typ./12 day min. at 40 degrees C (maintenance-free Super Capacitor)

PROFINET

1

2

Ethernet communication port

Real math execution speed

2.3 μs/instruction

Boolean execution speed

0.08 μs/instruction

1

The slower speed is applicable when the HSC is configured for quadrature mode of operation.

2

For CPU models with relay outputs, you must install a digital signal (SB) to use the pulse outputs.

3

Up to 200 kHz are available with the SB 1221 DI x 24 VDC 200 kHz and SB 1221 DI 4 x 5 VDC 200 kHz.

The different CPU models provide a diversity of features and capabilities that help you create

effective solutions for your varied applications. For detailed information about a specific

CPU, see the technical specifications (Page 361).

16

Introducing the powerful and flexible S7-1200

1.1 Introducing the S7-1200 PLC

Table 1- 2

Blocks, timers, and counters supported by S7-1200

Element

Description

Blocks

Type

OB, FB, FC, DB

Size

50 Kbytes (CPU 1211C)

75 Kbytes (CPU 1212C)

100 Kbytes (CPU 1214C)

125 Kbytes (CPU 1215C)

150 Kbytes (CPU 1217C)

Quantity

Up to 1024 blocks total (OBs + FBs + FCs + DBs)

Nesting depth

16 from the program cycle or startup OB;

6 from any interrupt event OB

Monitoring

Status of 2 code blocks can be monitored simultaneously

OBs

Program cycle

Multiple

Startup

Multiple

Time-delay interrupts

4 (1 per event)

Cyclic interrupts

4 (1 per event)

Hardware interrupts

50 (1 per event)

Time error interrupts

1

Diagnostic error interrupts

1

Pull or plug of modules

1

Rack or station failure

1

Time of day

Multiple

Status

1

Update

1

Profile

1

Timers

Type

IEC

Quantity

Limited only by memory size

Storage

Structure in DB, 16 bytes per timer

Counters

Type

IEC

Quantity

Limited only by memory size

Storage

Structure in DB, size dependent upon count type

• SInt, USInt: 3 bytes

• Int, UInt: 6 bytes

• DInt, UDInt: 12 bytes

17

Introducing the powerful and flexible S7-1200

1.2 Expansion capability of the CPU

1.2

Expansion capability of the CPU

The S7-1200 family provides a variety of modules and plug-in boards for expanding the

capabilities of the CPU with additional I/O or other communication protocols. For detailed

information about a specific module, see the technical specifications (Page 361).

① Communication module (CM) or communication processor (CP)

② CPU (CPU 1211C, CPU 1212C, CPU 1214C, CPU 1215C, CPU 1217C)

③ Signal board (SB) (digital SB, analog SB), communication board (CB), or Battery Board (BB)

CPU (CPU 1211C, CPU 1212C, CPU 1214C, CPU 1215C, CPU 1217C)

④ Signal module (SM) (digital SM, analog SM, thermocouple SM, RTD SM, technology SM)

18

Introducing the powerful and flexible S7-1200

1.3 S7-1200 modules

1.3

S7-1200 modules

Table 1- 3

S7-1200 expansion modules

Type of module

Description

The CPU supports one plug-in expansion

board:

• A signal board (SB) provides additional

I/O for your CPU. The SB connects on

the front of the CPU.

• A communication board (CB) allows

you to add another communication port

to your CPU.

• A battery board (BB) allows you to

provide long term backup of the

realtime clock.

① Status LEDs on the SB

② Removable user wiring connector

Signal modules (SMs) add additional func-

tionality to the CPU. SMs connect to the

right side of the CPU.

• Digital I/O

• Analog I/O

• RTD and thermocouple

• SM 1278 IO-Link Master

① Status LEDs

② Bus connector slide tab

③ Removable user wiring connector

Communication modules (CMs) and

communications processors (CPs) add

communication options to the CPU, such

as for PROFIBUS or RS232/RS485 con-

nectivity (for PtP, Modbus or USS), or the

AS-i master.

A CP provides capabilities for other types

of communication, such as connecting to

the CPU over a GPRS, IEC, DNP3, or

WDC network.

• The CPU supports up to three CMs or

CPs

19

Introducing the powerful and flexible S7-1200

1.4 Basic HMI panels

Type of module

Description

• Each CM or CP connects to the left

① Status LEDs

side of the CPU (or to the left side of

another CM or CP)

② Communication connector

1.4

Basic HMI panels

The SIMATIC HMI Basic Panels provide touch-screen devices for basic operator control and

monitoring tasks. All panels have a protection rating for IP65 and have CE, UL, cULus, and

NEMA 4x certification.

The available Basic HMI panels are described below:

● KTP400 Basic: 4" Touch screen with 4 configurable keys, a resolution of 480 x 272 and

800 tags

● KTP700 Basic: 7" Touch screen with 8 configurable keys, a resolution of 800 x 480 and

800 tags

● KTP700 Basic DP: 7" Touch screen with 8 configurable keys, a resolution of 800 x 480

and 800 tags

● KTP900 Basic: 9" Touch screen with 8 configurable keys, a resolution of 800 x 480 and

800 tags

● KTP1200 Basic: 12" Touch screen with 10 configurable keys, a resolution of 800 x 480

and 800 tags

● KTP 1200 Basic DP: 12 Touch screen with 10 configurable keys, a resolution of 800 x

400 and 800 tags

20

Introducing the powerful and flexible S7-1200

1.5 Mounting dimensions and clearance requirements

1.5

Mounting dimensions and clearance requirements

The S7-1200 PLC is designed to be easy to install. Whether mounted on a panel or on a

standard DIN rail, the compact size makes efficient use of space.

Refer to the S7-1200 Programmable Controller System Manual for specific requirements and

guidelines for installation.

21

Introducing the powerful and flexible S7-1200

1.5 Mounting dimensions and clearance requirements

Table 1- 4

Mounting dimensions (mm)

S7-1200 Devices

Width A

Width B

Width C

(mm)

(mm)

(mm)

CPU

CPU 1211C and CPU 1212C

90

45

--

CPU 1214C

110

55

--

CPU 1215C

130

65 (top)

Bottom:

C1: 32.5

C2: 65

C3: 32.5

CPU 1217C

150

75

Bottom:

C1: 37.5

C2: 75

C3: 37.5

Signal modules

Digital 8 and 16 point

45

22.5

--

Analog 2, 4, and 8 point

Thermocouple 4 and 8 point

RTD 4 point

SM 1278 IO Link-Master

Digital DQ 8 x Relay (Changeover)

70

35

--

Analog 16 point

70

35

--

RTD 8 point

Communication

CM 1241 RS232, and

30

15

--

interfaces

CM 1241 RS422/485

CM 1243-5 PROFIBUS master and

CM 1242-5 PROFIBUS slave

CM 1242-2 AS-i Master

CP 1242-7 GPRS V2

CP 1243-7 LTE-EU

CP 1243-1 DNP3

CP 1243-1 IEC

CP 1243-1

CP1243-1 PCC

CP 1243-8 ST7

RF120C

TS (TeleService) Adapter IE Advanced

1

TS (Teleservice) Adapter IE Basic ¹

TS Adapter

30

15

--

TS Module

30

15

--

1

Before installing the TS (TeleService) Adapter IE Advanced or IE Basic, you must first connect the

TS Adapter and a TS module. The total width ("width A") is 60 mm.

Each CPU, SM, CM, and CP supports mounting on either a DIN rail or on a panel. Use the

DIN rail clips on the module to secure the device on the rail. These clips also snap into an

extended position to provide screw mounting positions to mount the unit directly on a panel.

The interior dimension of the hole for the DIN clips on the device is 4.3 mm.

22

Introducing the powerful and flexible S7-1200

1.5 Mounting dimensions and clearance requirements

A 25 mm thermal zone must be provided above and below the unit for free air circulation.

The S7-1200 equipment is designed to be easy to install. You can install an S7-1200 either

on a panel or on a standard rail, and you can orient the S7-1200 either horizontally or

vertically. The small size of the S7-1200 allows you to make efficient use of space.

The S7-1200 fail-safe CPUs do not support PROFIBUS or PROFINET distributed fail-safe

I/O.

Electrical equipment standards classify the SIMATIC S7-1200 system as Open Equipment.

You must install the S7-1200 in a housing, cabinet, or electric control room. You should limit

entry to the housing, cabinet, or electric control room to authorized personnel.

The installation should provide a dry environment for the S7-1200. SELV/PELV circuits are

considered to provide protection against electric shock in dry locations.

The installation should provide mechanical and environmental protection that is approved for

open equipment in your particular location category according to applicable electrical and

building codes.

Conductive contamination due to dust, moisture, and airborne pollution can cause

operational and electrical faults in the PLC.

If you locate the PLC in an area where conductive contamination may be present, the PLC

must be protected by an enclosure with appropriate protection rating. IP54 is one rating that

is generally used for electronic equipment enclosures in dirty environments and may be

appropriate for your application.

WARNING

Improper installation of the S7-1200 can result in electrical faults or unexpected operation

of machinery.

Electrical faults or unexpected machine operation can result in death, severe personal

injury, and/or property damage.

All instructions for installation and maintenance of a proper operating environment must be

followed to ensure the equipment operates safely.

Separate the S7-1200 devices from heat, high voltage, and electrical noise

As a general rule for laying out the devices of your system, always separate the devices that

generate high voltage and high electrical noise from the low-voltage, logic-type devices such

as the S7-1200.

When configuring the layout of the S7-1200 inside your panel, consider the heat-generating

devices and locate the electronic-type devices in the cooler areas of your cabinet. Reducing

the exposure to a high-temperature environment will extend the operating life of any

electronic device.

Consider also the routing of the wiring for the devices in the panel. Avoid placing low-voltage

signal wires and communications cables in the same tray with AC power wiring and high-

energy, rapidly-switched DC wiring.

23

Introducing the powerful and flexible S7-1200

1.5 Mounting dimensions and clearance requirements

Provide adequate clearance for cooling and wiring

S7-1200 devices are designed for natural convection cooling. For proper cooling, you must

provide a clearance of at least 25 mm above and below the devices. Also, allow at least 25

mm of depth between the front of the modules and the inside of the enclosure.

CAUTION

For vertical mounting, the maximum allowable ambient temperature is reduced by 10

degrees C.

Orient a vertically mounted S7-1200 system as shown in the following figure.

Ensure that the S7-1200 system is mounted correctly.

When planning your layout for the S7-1200 system, allow enough clearance for the wiring

and communications cable connections.

① Side view

③ Vertical installation

② Horizontal installation

④ Clearance area

24

Introducing the powerful and flexible S7-1200

1.5 Mounting dimensions and clearance requirements

WARNING

Installation or removal of S7-1200 or related equipment with the power applied could cause

electric shock or unexpected operation of equipment.

Failure to disable all power to the S7-1200 and related equipment during installation or

removal procedures could result in death, severe personal injury and/or property damage

due to electric shock or unexpected equipment operation.

Always follow appropriate safety precautions and ensure that power to the S7-1200 is

disabled before attempting to install or remove S7-1200 CPUs or related equipment.

Always ensure that whenever you replace or install an S7-1200 device you use the correct

module or equivalent device.

WARNING

Incorrect installation of an S7-1200 module may cause the program in the S7-1200 to

function unpredictably.

Failure to replace an S7-1200 device with the same model, orientation, or order could result

in death, severe personal injury and/or property damage due to unexpected equipment

operation.

Replace an S7-1200 device with the same model, and be sure to orient and position it

correctly.

25

STEP 7 makes the work easy

2

STEP 7 provides a user-friendly environment to develop controller logic, configure HMI

visualization, and setup network communication. To help increase your productivity, STEP 7

provides two different views of the project: a task-oriented set of portals that are organized

on the functionality of the tools (Portal view), or a project-oriented view of the elements within

the project (Project view). Choose which view helps you work most efficiently. With a single

click, you can toggle between the Portal view and the Project view.

Portal view

① Portals for the different tasks

② Tasks for the selected portal

③ Selection panel for the selected

action

④ Changes to the Project view

Project view

① Menus and toolbar

② Project navigator

③ Work area

④ Task cards

⑤ Inspector window

⑥ Changes to the Portal view

⑦ Editor bar

With all of these components in one place, you have easy access to every aspect of your

project. For example, the inspector window shows the properties and information for the

object that you have selected in the work area. As you select different objects, the inspector

window displays the properties that you can configure. The inspector window includes tabs

that allow you to see diagnostic information and other messages.

By showing all of the editors that are open, the editor bar helps you work more quickly and

efficiently. To toggle between the open editors, simply click the different editor. You can also

arrange two editors to appear together, arranged either vertically or horizontally. This feature

allows you to drag and drop between editors.

29

STEP 7 makes the work easy

2.1 Easy to insert instructions into your user program

2.1

Easy to insert instructions into your user program

STEP 7 provides task cards that contain the instructions for your

program. The instructions are grouped according to function.

To create your program, you drag instructions from the task card

onto a network.

2.2

Easy access to your favorite instructions from a toolbar

STEP 7 provides a "Favorites" toolbar to give you quick access to the instructions that you

frequently use. Simply click the icon for the instruction to insert it into your network!

(For the "Favorites" in the instruction tree, double-

click the icon.)

You can easily customize the

"Favorites" by adding new in-

structions.

Simply drag and drop an instruc-

tion to the "Favorites".

The instruction is now just a click

away!

30

STEP 7 makes the work easy

2.3 Easy to add inputs or outputs to LAD and FBD instructions

2.3

Easy to add inputs or outputs to LAD and FBD instructions

Some of the instructions allow you to create additional inputs or outputs.

● To add an input or output, click the "Create" icon or right-click on an input stub for one of

the existing IN or OUT parameters and select the "Insert input" command.

● To remove an input or output, right-click on the stub for one of the existing IN or OUT

parameters (when there are more than the original two inputs) and select the "Delete"

command.

2.4

Expandable instructions

Some of the more complex instructions are expandable, displaying only the key inputs and

outputs. To display all the inputs and outputs, click the arrow at the bottom of the instruction.

31

STEP 7 makes the work easy

2.5 Easy to change the operating mode of the CPU

2.5

Easy to change the operating mode of the CPU

The CPU does not have a physical switch for changing the operating mode (STOP or RUN).

Use the "Start CPU" and "Stop CPU" toolbar buttons to change the operating

mode of the CPU.

When you configure the CPU in the device configuration, you configure the start-up behavior

in the properties of the CPU (Page 80).

The "Online and diagnostics" portal also provides an operator panel for changing the

operating mode of the online CPU. To use the CPU operator panel, you must be connected

online to the CPU. The "Online tools" task card displays an operator panel that shows the

operating mode of the online CPU. The operator panel also allows you to change the

operating mode of the online CPU.

Use the button on the operator panel to change the operating mode

(STOP or RUN). The operator panel also provides an MRES button for

resetting the memory.

The color of the RUN/STOP indicator shows the current operating mode of the CPU. Yellow

indicates STOP mode, and green indicates RUN mode.

From the device configuration in STEP 7 you can also configure the default operating mode

on power up of the CPU.

2.6

Easy to modify the appearance and configuration of STEP 7

You can select a variety of settings, such as the appearance of the interface, language, or

the folder for saving your work.

Select the "Settings" command from the "Options" menu to change these settings.

32

STEP 7 makes the work easy

2.7 Project and global libraries for easy access

2.7

Project and global libraries for easy access

The global and project libraries allow you to reuse the stored objects throughout a project or

across projects. For example, you can create block templates for use in different projects

and adapt them to the particular requirements of your automation task. You can store a

variety of objects in the libraries, such as FCs, FBs, DBs, device configuration, data types,

watch tables, process screens, and faceplates. You can also save the components of the

HMI devices in your project.

Each project has a project library for storing the objects to be

used more than once within the project. This project library is

part of the project. Opening or closing the project opens or

closes the project library, and saving the project saves any

changes in the project library.

You can create your own global library to store the objects you want to make available for

other projects to use. When you create a new global library, you save this library to a

location on your computer or network.

2.8

Easy to select a version of an instruction

The development and release cycles for certain sets of instructions (such as Modbus, PID

and motion) have created multiple released versions for these instructions. To help ensure

compatibility and migration with older projects, STEP 7 allows you to choose which version

of instruction to insert into your user program.

Click the icon on the instruction tree task card

to enable the headers and columns of the

instruction tree.

To change the version of the instruction, se-

lect the appropriate version from the drop-

down list.

33

STEP 7 makes the work easy

2.9 Easy to drag and drop between editors

2.9

Easy to drag and drop between editors

To help you perform tasks quickly and easily,

STEP 7 allows you to drag and drop elements

from one editor to another. For example, you

can drag an input from the CPU to the address

of an instruction in your user program.

You must zoom in at least 200% to select the

inputs or outputs of the CPU.

Notice that the tag names are displayed not

only in the PLC tag table, but also are dis-

played on the CPU.

To display two editors at one time, use the

"Split editor" menu commands or buttons in

the toolbar.

To toggle between the editors that have been opened, click the icons in the editor bar.

34

STEP 7 makes the work easy

2.10 Changing the call type for a DB

2.10

Changing the call type for a DB

STEP 7 allows you to easily create or change the associ-

ation of a DB for an instruction or an FB that is in an FB.

• You can switch the association between different DBs.

• You can switch the association between a single-

instance DB and a multi-instance DB.

• You can create an instance DB (if an instance DB is

missing or not available).

You can access the "Change call type" command either

by right-clicking the instruction or FB in the program edi-

tor or by selecting the "Block call" command from the

"Options" menu.

The "Call options" dialog allows

you to select a single-instance

or multi-instance DB. You can

also select specific DBs from a

drop-down list of available DBs.

35

STEP 7 makes the work easy

2.11 Temporarily disconnecting devices from a network

2.11

Temporarily disconnecting devices from a network

You can disconnect individual network devices from the subnet. Because the configuration of

the device is not removed from the project, you can easily restore the connection to the

device.

Right-click the interface port of the network

device and select the "Disconnect from sub-

net" command from the context menu.

STEP 7 reconfigures the network connections, but does not remove the disconnected device

from the project. While the network connection is deleted, the interface addresses are not

changed.

When you download the new network connections, the CPU must be set to STOP mode.

To reconnect the device, simply create a new network connection to the port of the device.

36

STEP 7 makes the work easy

2.12 Easy to virtually "unplug" modules without losing the configuration

2.12

Easy to virtually "unplug" modules without losing the configuration

STEP 7 provides a storage area for "un-

plugged" modules. You can drag a module

from the rack to save the configuration of

that module. These unplugged modules

are saved with your project, allowing you

to reinsert the module in the future without

having to reconfigure the parameters.

One use of this feature is for temporary

maintenance. Consider a scenario where

you might be waiting for a replacement

module and plan to temporarily use a dif-

ferent module as a short-term replace-

ment. You could drag the configured

module from the rack to the "Unplugged

modules" and then insert the temporary

module.

37

Getting started

3

3.1

Create a project

Working with STEP 7 is easy! See how quickly you can get started with creating a project.

In the Start portal, click the

"Create new project" task.

Enter a project name and click

the "Create" button.

After creating the project, select the Devices &

Networks portal.

Click the "Add new device" task.

Select the CPU to add to the project:

1. In the "Add new device" dialog, click the

"SIMATIC PLC" button.

2. Select a CPU from the list.

3. To add the selected CPU to the project, click

the "Add" button.

Note that the "Open device view" option is select-

ed. Clicking "Add" with this option selected opens

the "Device configuration" of the Project view.

The Device view displays the

CPU that you added.

39

Getting started

3.2 Create tags for the I/O of the CPU

3.2

Create tags for the I/O of the CPU

"PLC tags" are the symbolic names for I/O and addresses. After you create a PLC tag,

STEP 7 stores the tag in a tag table. All of the editors in your project (such as the program

editor, the device editor, the visualization editor, and the watch table editor) can access the

tag table.

With the device editor open, open a tag table.

You can see the open editors displayed in the editor bar.

In the tool bar, click the "Split editor space horizontally" button.

STEP 7 displays both the tag table and the de-

vice editor together.

Zoom the device configuration to over 200% so that the I/O points of the CPU are legible and

selectable. Drag the inputs and outputs from the CPU to the tag table:

1. Select I0.0 and drag it to the first row of the tag table.

2. Change the tag name from "I0.0" to "Start".

3. Drag I0.1 to the tag table and change the name to "Stop".

4. Drag Q0.0 (on the bottom of the CPU) to the tag table and change the name to

"Running".

40

Getting started

3.2 Create tags for the I/O of the CPU

With the tags entered into the PLC tag table, the tags are available to your user program.

41

Getting started

3.3 Create a simple network in your user program

3.3

Create a simple network in your user program

Your program code consists of instructions that the CPU executes in sequence. For this

example, use ladder logic (LAD) to create the program code. The LAD program is a

sequence of networks that resemble the rungs of a ladder.

To open the program editor, follow these steps:

1. Expand the "Program blocks" folder in the Project tree to

display the "Main [OB1]" block.

2. Double-click the "Main [OB1]" block.

The program editor opens the program block (OB1).

Use the buttons on the "Favorites" to insert contacts and coils onto the network.

1. Click the "Normally open contact"

button on the "Favorites" to add a

contact to the network.

2. For this example, add a second

contact.

3. Click the "Output coil" button to

insert a coil.

The "Favorites" also provides a button for creating a branch

1. Select the left rail to select the rail

for the branch.

2. Click the "Open branch" icon to

add a branch to the rail of the

network.

3. Insert another normally open

contact to the open branch.

4. Drag the double-headed arrow to a

connection point (the green square

on the rung) between the two

contacts on the first rung.

42

Getting started

3.4 Use the PLC tags in the tag table for addressing the instructions

3.4

Use the PLC tags in the tag table for addressing the instructions

Using the tag table, you can quickly enter the PLC tags for the addresses of the contacts and

coils.

1. Double-click the default address

<??.?> above the first normally

open contact.

2. Click the selector icon to the right

of the address to open the tags in

the tag table.

3. From the drop-down list, select

"Start" for the first contact.

4. For the second contact, repeat the

preceding steps and select the tag

"Stop".

5. For the coil and the latching

contact, select the tag "Running".

You can also drag the I/O addresses directly

from the CPU. Simply split the work area of the

Project view (Page 34).

You must zoom the CPU to over 200% in order

to select the I/O points.

You can drag the I/O on the CPU in the "Device

configuration" to the LAD instruction in the pro-

gram editor to create not only the address for the

instruction, but also to create an entry in the PLC

tag table.

44

Getting started

3.5 Add a "box" instruction

3.5

Add a "box" instruction

The program editor features a generic "box" instruction. After inserting this box instruction,

you then select the type of instruction, such as an ADD instruction, from a drop-down list.

Click the generic "box" instruction in

the "Favorites" tool bar.

The generic "box" instruction supports

a variety of instructions. For this ex-

ample, create an ADD instruction:

1. Click the yellow corner of the box

instruction to display the drop-

down list of instructions.

2. Scroll down the list and select the

ADD instruction.

3. Click the yellow corner by the "?" to

select the data type for the inputs

and output.

You can now enter the tags (or

memory addresses) for the values to

use with the ADD instruction.

You can also create additional inputs for certain instructions:

1. Click one of the inputs inside the box.

2. Right-click to display the context menu and select the "Insert

input" command.

The ADD instruction now uses three inputs.

45

Getting started

3.6 Use the CALCULATE instruction for a complex mathematical equation

3.6

Use the CALCULATE instruction for a complex mathematical

equation

The Calculate instruction (Page 111) lets you create a math function that operates on multi-

ple input parameters to produce the result, according to the equation that you define.

In the Basic instruction tree, expand the Math functions folder.

Double-click the Calculate instruction to insert the instruction

into your user program.

The unconfigured Calculate instruc-

tion provides two input parameters

and an output parameter.

Click the "???" and select the data types for the input and output pa-

rameters. (The input and output parameters must all be the same data

type.)

For this example, select the "Real" data type.

Click the "Edit equation" icon to enter the equation.

46

Getting started

3.6 Use the CALCULATE instruction for a complex mathematical equation

For this example, enter the following equation for scaling a raw analog value. (The "In" and

"Out" designations correspond to the parameters of the Calculate instruction.)

Out value

= ((Out high - Out low) / (In high - In low)) * (In value - In low) + Out low

Out

= ((in4 - in5) / (in2 - in3)) * (in1 - in3) + in5

Where:

Out value

(Out)

Scaled output value

In value

(in1)

Analog input value

In high

(in2)

Upper limit for the scaled input value

In low

(in3)

Lower limit for the scaled input value

Out high

(in4)

Upper limit for the scaled output value

Out low

(in5)

Lower limit for the scaled output value

In the "Edit Calculate" box, enter the equation with the parameter names:

OUT = ((in4 - in5) / (in2 - in3)) * (in1 - in3) + in5

When you click "OK", the Calculate

instruction creates the inputs re-

quired for the instruction.

Enter the tag names for the values

that correspond to the parameters.

47

Getting started

3.7 Add an HMI device to the project

3.7

Add an HMI device to the project

Adding an HMI device to your project is

easy!

1. Double-click the "Add new device" icon.

2. Click the "SIMATIC HMI" button in the

Add new device" dialog.

3. Select the specific HMI device from the

list.

You can choose to run the HMI wizard

to help you configure the screens for

the HMI device.

4. Click "OK" to add the HMI device to

your project.

The TIA Portal adds the HMI device to the project.

The TIA Portal provides an HMI wizard that helps you

configure all of the screens and structure for your HMI

device.

If you do not run the HMI wizard, the TIA Portal creates a simple default HMI screen. You

can add additional screens or objects on screens later.

48

Getting started

3.8 Create a network connection between the CPU and HMI device

3.8

Create a network connection between the CPU and HMI device

Creating a network is easy!

• Go to "Devices and Networks" and select the

Network view to display the CPU and HMI

device.

• To create a PROFINET network, drag a line

from the green box (Ethernet port) on one

device to the green box on the other device.

A network connection is created for the two devic-

es.

3.9

Create an HMI connection to share tags

By creating an HMI connection between the

two devices, you can easily share the tags

between the two devices.

• With the network connection selected, click

the "Connections" button and select "HMI

connection" from the drop-down list.

• The HMI connection turns the two devices

blue.

• Select the CPU device and drag the line to

the HMI device.

• The HMI connection allows you to configure

the HMI tags by selecting a list of PLC tags.

49

Getting started

3.10 Create an HMI screen

You can use other options for creating an HMI connection:

● Dragging a PLC tag from the PLC tag table, the program editor or the device

configuration editor to the HMI screen editor automatically creates an HMI connection.

● Using the HMI wizard to browse for the PLC automatically creates the HMI connection.

3.10

Create an HMI screen

Even if you do not utilize the HMI wizard, configuring an HMI screen is easy.

STEP 7 provides a standard set of librar-

ies for inserting basic shapes, interactive

elements, and even standard graphics.

To add an element, simply drag and drop one of the elements onto the screen. Use the

properties for the element (in the Inspector window) to configure the appearance and

behavior of the element.

You can also create elements on your screen by dragging and dropping PLC tags either

from the Project tree or the program editor to the HMI screen. The PLC tag becomes an

element on the screen. You can then use the properties to change the parameters for this

element.

50

Getting started

3.11 Select a PLC tag for the HMI element

3.11

Select a PLC tag for the HMI element

After you create the element on your screen, use the properties of the element to assign a

PLC tag to the element. Click the selector button by the tag field to display the PLC tags of

the CPU.

You can also drag and drop PLC tags from the Project tree to the HMI screen. Display the

PLC tags in the "Details" view of the project tree and then drag the tag to the HMI screen.

51

PLC concepts made easy

4

4.1

Tasks performed every scan cycle

Each scan cycle includes writing the outputs, reading the inputs, executing the user program

instructions, and performing system maintenance or background processing.

The cycle is referred to as a scan cycle or scan. Under

default conditions, all digital and analog I/O points are

updated synchronously with the scan cycle using an in-

ternal memory area called the process image. The pro-

cess image contains a snapshot of the physical inputs

and outputs on the CPU, signal board, and signal mod-

ules.

● The CPU reads the physical inputs just prior to the execution of the user program and

stores the input values in the process image input area. This ensures that these values

remain consistent throughout the execution of the user instructions.

● The CPU executes the logic of the user instructions and updates the output values in the

process image output area instead of writing to the actual physical outputs.

● After executing the user program, the CPU writes the resulting outputs from the process

image output area to the physical outputs.

53

PLC concepts made easy

4.2 Operating modes of the CPU

This process provides consistent logic through the execution of the user instructions for a

given cycle and prevents the flickering of physical output points that might change state

multiple times in the process image output area.

STARTUP

RUN

A Clears the I (image) memory area

① Writes Q memory to the physical outputs

B Initializes the Q output (image) memory

② Copies the state of the physical inputs to I

area with either zero, the last value, or

memory

the substitute value, as configured, and

zeroes PB, PN, and AS-i outputs

C Initializes non-retentive M memory and

③ Executes the program cycle OBs

data blocks to their initial value and

enables configured cyclic interrupt and

time of day events.

Executes the startup OBs.

D Copies the state of the physical inputs to

④ Performs self-test diagnostics

I memory

E Stores any interrupt events into the

⑤ Processes interrupts and communications

queue to be processed after entering

during any part of the scan cycle

RUN mode

F Enables the writing of Q memory to the

physical outputs

You can change the default behavior for a module by removing it from this automatic update

of I/O. You can also immediately read and write digital and analog I/O values to the modules

when an instruction executes. Immediate reads of physical inputs do not update the process

image input area. Immediate writes to physical outputs update both the process image

output area and the physical output point.

54

PLC concepts made easy

4.2 Operating modes of the CPU

4.2

Operating modes of the CPU

The CPU has three modes of operation: STOP mode, STARTUP mode, and RUN mode.

Status LEDs on the front of the CPU indicate the current mode of operation.

● In STOP mode, the CPU is not executing the program, and you can download a project.

The RUN/STOP LED is solid yellow.

● In STARTUP mode, the CPU executes any startup logic (if present). The CPU does not

process interrupt events during the startup mode. The RUN/STOP LED alternates

flashing between green and yellow.

● In RUN mode, the scan cycle executes repeatedly. Interrupt events can occur and the

CPU can process them at any point within the program cycle phase. You can download

some parts of a project in RUN mode. The RUN/STOP LED is solid green.

The CPU supports the warm restart method for entering the RUN mode. Warm restart does

not include a memory reset, but you can command a memory reset from STEP 7. A memory

reset clears all work memory, clears retentive and non-retentive memory areas, copies load

memory to work memory, and sets outputs to the configured "Reaction to CPU STOP". A

memory reset does not clear the diagnostics buffer or the permanently saved IP address. A

warm restart initializes all non-retentive system and user data.

You can configure the "startup after POWER ON" setting of the CPU complete with restart

method using STEP 7. This configuration item appears under the Device Configuration for

the CPU under Startup. At power up, the CPU performs a sequence of power-up diagnostic

checks and system initialization. During system initialization, the CPU deletes all non-

retentive bit memory and resets all non-retentive DB contents to initial values. The CPU then

enters the appropriate power-up mode. Certain errors will prevent the CPU from entering the

RUN mode. The CPU supports the following power-up modes: STOP mode, "Go to RUN

mode after warm restart", and "Go to previous mode after warm restart".

NOTICE

Warm restart mode configuration

The CPU can enter STOP mode due to repairable faults, such as failure of a replaceable

signal module, or temporary faults, such as power line disturbance or erratic power up

event.

If the CPU has been configured to "Warm restart mode prior to POWER OFF", it will not

return to RUN mode when the fault is repaired or removed until it receives a new command

from STEP 7 to go to RUN. Without a new command, the STOP mode is retained as the

mode prior to POWER OFF.

CPUs that are intended to operate independently of a STEP 7 connection should typically

be configured to "Warm restart - RUN" so that the CPU can be returned to RUN mode by a

power cycle following the removal of fault conditions.

The CPU does not provide a physical switch for changing the operat-

ing mode. To change the operating mode of the CPU, STEP 7 pro-

vides the following tools:

• "Stop" and "Run" buttons on the STEP 7 toolbar

• CPU operator panel in the online tools

55

PLC concepts made easy

4.3 Execution of the user program

4.3.3

Event execution priorities and queuing

The CPU processing is controlled by events. An event triggers an interrupt OB to be

executed. You can specify the interrupt OB for an event during the creation of the block,

during the device configuration, or with an ATTACH or DETACH instruction. Some events

happen on a regular basis like the program cycle or cyclic events. Other events happen only

a single time, like the startup event and time delay events. Some events happen when the

hardware triggers an event, such as an edge event on an input point or a high speed counter

event. Events like the diagnostic error and time error event only happen when an error

occurs. The event priorities and queues are used to determine the processing order for the

event interrupt OBs.

The CPU processes events in order of priority where 1 is the lowest priority and 26 is the

highest priority. Prior to V4.0 of the S7-1200 CPU, each type of OB belonged to a fixed

priority class (1 to 26). From V4.0 forward, you can assign a priority class to each OB that

you configure. You configure the priority number in the attributes of the OB properties.

Interruptible and non-interruptible execution modes

OBs (Page 57) execute in priority order of the events that trigger them. From V4.0 forward,

you can configure OB execution to be interruptible or non-interruptible. Note that program

cycle OBs are always interruptible, but you can configure all other OBs to be either

interruptible or non-interruptible.

If you set interruptible mode, then if an OB is executing and a higher priority event occurs

before the OB completes its execution, the running OB is interrupted to allow the higher-

priority event OB to run. The higher-priority event runs, and at its completion, the OB that

was interrupted continues. When multiple events occur while an interruptible OB is

executing, the CPU processes those events in priority order.

If you do not set interruptible mode, then an OB runs to completion when triggered

regardless of any other events that trigger during the time that it is running.

Consider the following two cases where interrupt events trigger a cyclic OB and a time delay

OB. In both cases, the time delay OB (OB201) has no process image partition assignment

and executes at priority 4. The cyclic OB (OB200) has a process image partition assignment

of PIP1 and executes at priority 2. The following illustrations show the difference in execution

between non-interruptible and interruptible execution modes:

Figure 4-1

Case 1: Non-interruptible OB execution

58

PLC concepts made easy

4.3 Execution of the user program

Figure 4-2

Case 2: Interruptible OB execution

Note

If you configure the OB execution mode to be non-interruptible, then a time error OB cannot

interrupt OBs other than program cycle OBs. Prior to V4.0 of the S7-1200 CPU, a time error

OB could interrupt any executing OB. From V4.0 forward, you must configure OB execution

to be interruptible if you want a time error OB (or any other higher priority OB) to be able to

interrupt executing OBs that are not program cycle OBs.

Understanding event execution priorities and queuing

The CPU limits the number of pending (queued) events from a single source, using a

different queue for each event type. Upon reaching the limit of pending events for a given

event type, the next event is lost. You can use a time error interrupt OB to respond to queue

overflows.

Each CPU event has an associated priority. In general, the CPU services events in order of

priority (highest priority first). The CPU services events of the same priority on a "first-come,

first-served" basis.

Table 4- 1

OB events

Event

Quantity allowed

Default OB priority

Program cycle

1 program cycle event

1⁴

Multiple OBs allowed

Startup

1 startup event ¹

1⁴

Multiple OBs allowed

Time delay

Up to 4 time events

3

1 OB per event

Cyclic interrupt

Up to 4 events

8

1 OB per event

Hardware interrupt

Up to 50 hardware interrupt events²

18

1 OB per event, but you can use the same OB for

18

multiple events

Time error

1 event (only if configured)³

22 or 26⁴

Diagnostic error

1 event (only if configured)

5

Pull or plug of modules

1 event

6

59

PLC concepts made easy

4.3 Execution of the user program

Event

Quantity allowed

Default OB priority

Rack or station failure

1 event

6

Time of day

Up to 2 events

2

Status

1 event

4

Update

1 event

4

Profile

1 event

4

1

The startup event and the program cycle event never occur at the same time because the startup

event runs to completion before the program cycle event starts.

2

You can have more than 50 hardware interrupt event OBs if you use the DETACH and ATTACH

instructions.

3

You can configure the CPU to stay in RUN if the scan cycle exceeds the maximum scan cycle time

or you can use the RE_TRIGR instruction to reset the cycle time. However, the CPU goes to

STOP mode the second time that one scan cycle exceeds the maximum scan cycle time.

4

The priority for a new V4.0 or V4.1 CPU is 22. If you exchange a V3.0 CPU for a V4.0 or V4.1

CPU, the priority is 26: the priority that was in effect for V3.0. In either case, the priority field is ed-

itable and you can set the priority to any value in the range 22 to 26.

Refer to the topic "Exchanging a V3.0 CPU for a V4.1 CPU (Page 433)" for more details.

In addition, the CPU recognizes other events that do not have associated OBs. The following

table describes these events and the corresponding CPU actions:

Table 4- 2

Additional events

Event

Description

CPU action

I/O access error

Direct I/O read/write error

The CPU logs the first occurrence in the

diagnostic buffer and stays in RUN mode.

Max cycle time error

CPU exceeds the configured

The CPU logs the error in the diagnostic

cycle time twice

buffer and transitions to STOP mode.

Peripheral access error

I/O error during process im-

The CPU logs the first occurrence in the

age update

diagnostic buffer and stays in RUN mode.

Programming error

program execution error

If the block with the error provides error

handling, it updates the error structure; if

not, the CPU logs the error in the diagnos-

tic buffer and stays in RUN mode.

Interrupt latency

The interrupt event latency (the time from notification of the CPU that an event has occurred

until the CPU begins execution of the first instruction in the OB that services the event) is

approximately 175 µsec, provided that a program cycle OB is the only event service routine

active at the time of the interrupt event.

60

PLC concepts made easy

4.4 Memory areas, addressing and data types

4.4

Memory areas, addressing and data types

The CPU provides the following memory areas to store the user program, data, and

configuration:

● Load memory is non-volatile storage for the user program, data and configuration. When

a project is downloaded to the CPU, it is first stored in the Load memory area. This area

is located either in a memory card (if present) or in the CPU. This non-volatile memory

area is maintained through a power loss. You can increase the amount of load memory

available for data logs by installing a memory card.

● Work memory is volatile storage for some elements of the user project while executing

the user program. The CPU copies some elements of the project from load memory into

work memory. This volatile area is lost when power is removed, and is restored by the

CPU when power is restored.

● Retentive memory is non-volatile storage for a limited quantity of work memory values.

The retentive memory area is used to store the values of selected user memory locations

during power loss. When a power down or power loss occurs, the CPU restores these

retentive values upon power up.

An optional SIMATIC memory card provides an alternative memory for

storing your user program or a means for transferring your program. If you

use the memory card, the CPU runs the program from the memory card

and not from the memory in the CPU.

Check that the memory card is not write-protected. Slide the protection

switch away from the "Lock" position.

Use the optional SIMATIC memory card as a program card, as a transfer card, for collecting

data log files, or to perform a firmware update.

● Use the transfer card to copy your project to multiple CPUs without using STEP 7. The

transfer card copies a stored project from the card to the memory of the CPU. You must

remove the transfer card after copying the program to the CPU.

● The program card takes the place of CPU memory; all of your CPU functions are

controlled by the program card. Inserting the program card erases all of the internal load

memory of the CPU (including the user program and any forced I/O). The CPU then

executes the user program from the program card.

● You can also use the program card for collecting data log files (Page 122). The program

card provides more memory than the internal memory of the CPU. The Web server

function (Page 253) of the CPU allows you to download the data log files to a computer.

● You can also use a memory card to perform a firmware update. Refer to the S7-1200

Programmable Controller System Manual for instructions.

Note

The program card must remain in the CPU. If you remove the program card, the CPU goes

to STOP mode.

61

PLC concepts made easy

4.4 Memory areas, addressing and data types

4.4.1

Data types supported by the S7-1200

Data types are used to specify both the size of a data element as well as how the data are to

be interpreted. Each instruction parameter supports at least one data type, and some

parameters support multiple data types. Hold the cursor over the parameter field of an

instruction to see which data types are supported for a given parameter.

Table 4- 3

Data types supported by the S7-1200

Data types

Description

Bit and bit-sequence

•

Bool is a Boolean or bit value.

data types

•

Byte is an 8-bit byte value.

•

Word is a 16-bit value.

•

DWord is a 32-bit double-word value.

Integer data types

•

USInt (unsigned 8-bit integer) and SInt (signed 8-bit integer) are "short" integers (8 bits or 1

byte of memory) that can be signed or unsigned.

•

UInt (unsigned 16-bit integer) and Int (signed 16-bit integer) are integers (16 bits or 1 word of

memory) that can be signed or unsigned.

•

UDInt (unsigned 32-bit integer) and DInt (signed 32-bit integer) are double integers (32 bits or

1 double-word of memory) that can be signed or unsigned.

Real number data

•

Real is a 32-bit Real number or floating-point value.

types

•

LReal is a 64-bit Real number or floating-point value.

Date and time data

•

Date is a 16-bit date value (similar to a UInt) that contains the number of days since January

types

1, 1990. The maximum date value is 65378 (16#FF62), which corresponds to December 31,

2168. All possible Date values are valid.

•

DTL (date and time long) is a structure of 12 bytes that saves information on date and time in

a predefined structure.

- Year (UInt): 1970 to 2554

- Month (USInt): 1 to 12

- Day (USInt): 1 to 31

- Weekday (USInt): 1 (Sunday) to 7 (Saturday)

- Hours (USInt): 0 to 23

- Minutes (USInt): 0 to 59

- Seconds (USInt): 0 to 59

- Nanoseconds (UDInt): 0 to 999999999

•

Time is a 32-bit IEC time value (similar to a Dint) that stores the number of milliseconds (from

0 to 24 days 20 hours 31 minutes 23 seconds and 647 ms). All possible Time values are val-

id. Time values can be used for calculations, and negative times are possible.

•

TOD (time of day) is a 32-bit time-of-day value (similar to a Dint) that contains the number of

milliseconds since midnight (from 0 to 86399999).

Character and string

•

Char is an 8-bit single character.

data types

•

String is a variable-length string of up to 254 characters.

62

Content      ..      1       2         ..

///////////////////////////////////////