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User Manual

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Example

This example uses the Addition and Subtraction functions to keep track of the number of
parts in a temporary storage area. Each time a part enters the storage area, power flows
through relay %I0004 to a positive transition coil with reference %M0001. Relay %M0001
then enables the Addition function, adding the (constant) value 1 to the current total value
in %R0201.

Each time a part leaves the storage area, power flows through relay %I0005 to a positive
transition coil with reference %M0002. Relay %M0002 then enables the Subtraction
function, subtracting the (constant) value 1 from the current total value in %R0201.

Figure 300

23.5.4

Math and Numerical Functions
Modulo Division

The Modulo Division function divides one value by another of the same data type, to obtain
the remainder. The sign of the result is always the same as the sign of input parameter IN1.
The Modulo function operates on these types of data:

INT

Signed integer

DINT

Double precision signed integer

When the function receives power flow, it divides input IN1 by input IN2. These parameters
must be the same data type. Output Q is calculated using the formula:

Q = IN1-((IN1 DIV I2) * I2)

The division produces an integer number. Q is the same data type as inputs IN1 and IN2. OK
is always ON when the function receives power flow, unless there is an attempt to divide by
zero. In that case, it is set OFF.

Figure 301

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Parameters of the Modulo Division Function

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is performed.

IN1

All data types: R, AI, AQ,
constant
INT data type only: I, Q,
M, T, G

IN1 contains a constant or reference for the value to be
divided by IN2. Range for constants in double precision
signed integer operations is minimum/maximum DINT.

IN2

All data types: R, AI, AQ,
constant
INT data type only: I, Q,
M, T, G

IN2 contains a constant or reference for the value to be
divided into IN1. Range for constants in double precision
signed integer operations is minimum/maximum DINT.

flow, none

The OK output is energized when the function is performed
without overflow.

All data types: R, AI, AQ
INT data type only: I, Q,
M, T, G

Output Q contains the result of dividing IN1 by IN2 to
obtain a remainder.

Example

In the example, the remainder of the integer division of BOXES into PALLETS is placed into
NT_FULL whenever %I0001 is ON.

Figure 302

23.5.5

Math and Numerical Functions Scaling

The Scaling function scales an input parameter and places the result in an output location.
For integer-type data, all parameters must be integer-based (signed). For word-type data,
all parameters must be word-based (unsigned).

Figure 303

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Parameters of the Scaling Function

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is performed.

IHI
ILO

R ,AI, AQ,
constant

IHI and ILO contain a constant or reference for the upper and lower limits
of the unscaled data. These limits, together with the values for OHI and
OLO, are used to calculate the scaling factor that will be applied to the input
value IN.

OHI
OLO

R ,AI, AQ,
constant

OHI and OLO contain a constant or reference for the upper and lower limits
of the scaled data.

R, AI, AQ,
constant

IN contains a constant or reference for the actual value to be scaled.

flow, none

The OK output is energized when the function is performed without
overflow.

OUT

R, AI, AQ

Output OUT contains the scaled equivalent of the input value.

Example

In the example, the registers %R0120 through %R0123 are used to store the high and low
scaling values. The input value to be scaled is analog input %AI0017. The scaled output data
is used to control analog output %AQ0017. The scaling is performed whenever %I0001 is
ON.

Figure 304

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23.5.6

Math and Numerical Functions Square Root

The Square Root function finds the square root of a value. When the function receives power
flow, the value of output Q is set to the integer portion of the square root of the input IN.
The output Q must be the same data type as IN.

The Square Root function operates on these types of data:

INT

Signed integer

DINT

Double precision signed integer

REAL

Floating Point

OK is set ON if the function is performed without overflow, unless one of these invalid REAL
operations occurs:

•

IN < 0

•

IN is NaN (Not a Number)

Otherwise, OK is set OFF.

Figure 305

Parameters of the Square Root Function

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is
performed.

All data types: R, AI, AQ, constant
INT data type only: I, Q, M, T, G

A constant or reference for the value whose square
root is to be calculated.  If IN is less than zero, the
function  will  not  pass  power  flow.  Range  for
constants  is  minimum/maximum  DINT  for  double
precision signed integer operations.

flow, none

The OK output is energized when the function is
performed without overflow, unless an invalid
operation occurs.

All data types: R, AI, AQ
INT data type only: I, Q, M, T, G

Output Q contains the square root of IN.

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Example

In the example, the square root of the integer number located at %AI001 is placed into the
result located at %R0003 whenever %I0001 is ON.

Figure 306

23.5.7

Math and Numerical Functions Trigonometric Functions

There are six Trigonometric functions: Sine, Cosine, Tangent, Inverse Sine, Inverse Cosine,
and Inverse Tangent.

Sine, Cosine, and Tangent

When a Sine, Cosine, or Tangent function receives power flow, it operates on IN, whose units
are radians, and stores the result in output Q. Both IN and Q are floating-point values.

Figure 307

The Sine, Cosine, and Tangent functions accept a broad range of input values, where

–

263 < IN <+263, (263 = 9.22x1018)

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Inverse Sine, Cosine, and Tangent

When an Inverse Sine, Cosine, or Tangent function receives power flow, it operates on IN
and stores the result in output Q, whose units are radians. Both IN and Q are floating-point
values.

The Inverse Sine and Cosine functions accept a narrow range of input values, where

-1 < IN < 1.

Given a valid value for the IN parameter, the Inverse Sine Real function produces a result Q
such that:

ASIN(IN) = -

π/2 ≤ Q ≤ π/2.

The Inverse Cosine Real function produces a result Q such that:

ACOS(IN) = 0 ≤ Q ≤ π.

The Inverse Tangent function accepts the broadest range of input values, where

∞ ≤ IN ≤ +∞.

Given a valid value for the IN parameter, the Inverse Tangent Real function produces a
result Q such that:

ATAN(IN) = -

π/2 ≤ Q ≤ π/2.

Parameters of the Trigonometric Functions

Input/Output Choices

Description

enable

flow

When the function is enabled, the operation is performed.

R, AI, AQ,
constant

IN contains the constant or reference real value to be operated
on.

flow, none

OK is energized when the function is performed without
overflow, unless an invalid operation occurs and/or IN is NaN.

R, AI, AQ

Output Q contains the trigonometric value of IN.

Example

In the example, the Cosine of the value in %R0001 is placed in %R0033.

Figure 308

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23.5.8

Math and Numerical Functions Logarithmic /
Exponential Functions

When a Logarithmic or Exponential function receives power flow, it performs the
appropriate logarithmic/exponential operation on the Real value in input IN and places the
result in output Q.

•

For the Base 10 Logarithm (LOG) function, the base 10 logarithm of IN is placed in
Q.

•

For the Natural Logarithm (LN) function, the natural logarithm of IN is placed in Q.

•

For the Power of E (EXP) function, e is raised to the power specified by IN and the
result is placed in Q.

•

For the Power of X (EXPT) function, the value of input IN1 is raised to the power
specified by the value IN2 and the result is placed in output Q. (The EXPT function
has three input parameters and two output parameters.)

The OK output receives power flow unless the input is NaN (Not a Number) or is negative.

Figure 309

Parameters of the Logarithmic/Exponential Functions

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is performed.

IN or
IN1, IN2

R, AI, AQ,
constant

For EXP, LOG, and LN, IN contains the real value to be operated on.
The EXPT function has two inputs, IN1 and IN2. For EXPT, IN1 is the
base value and IN2 is the exponent.

flow, none

OK is energized when the function is performed without overflow,
unless an invalid operation occurs and/or IN is NaN or is negative.

R, AI, AQ

Output Q contains the logarithmic/exponential value of IN.

Example of the EXPT Function

In the example, the value of %AI001 is raised to the power of 2.5 and the result is placed in
%R0001.

Figure 310

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23.5.9

Math and Numerical Functions Radian Conversion
Functions

When Degree/Radian Conversion function receives power flow, the appropriate conversion
(radians to degrees or degrees to radians) is performed on the Real value in input IN and the
result is placed in output Q.

The OK output will receive power flow unless IN is NaN (Not a Number).

Figure 311

Parameters of the Radian Conversion Function

Input/Output Choices

Description

enable

flow

When the function is enabled, the operation is performed.

R, AI, AQ, constant IN contains the real value to be operated on.

flow, none

The OK output is energized when the function is
performed without overflow, unless IN is NaN.

R, AI, AQ

Output Q contains the converted value of IN.

Example

In the example, +1500 is converted to DEG and is placed in %R0001.

Figure 312

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23.6

Relational Functions

The Relational functions can be used to compare two numbers and to determine whether a
number lies within a specified range.

•

Equal

Test two numbers for equality

•

Not Equal

Test two numbers for non-equality

•

Greater Than

Test whether one number is greater than another

•

Greater Than or Equal Test whether one number is greater than or equal to

another

•

Less Than

Test whether one number is less than another

•

Less Than or Equal

Test whether one number is less than or equal to another

•

Range

Tests whether one number lies between two other
numbers

When the function receives power flow, it compares input IN1 to input IN2. These
parameters must be the same data type.

Figure 313

If inputs IN1 and IN2 match the specified relational condition, output Q receives power
flow and is set ON (1); otherwise, it is set OFF (0).

23.6.1

Data Types for Relational Functions

Relational functions operate on these types of data:

INT

Signed integer

DINT

Double precision signed integer

REAL

Floating Point

The %S0020 bit is set ON when a relational function using Real data executes successfully.
It is cleared when either input is NaN (Not a Number).

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23.6.2

Relational Functions Equal, Not Equal, Less Than,
Less/Equal, Greater Than, Greater/Equal

Parameters for the Relational Functions

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is performed.

IN1

R, AI, AQ, constant
For INT data only: I, Q,
M, T, G

IN1 contains a constant or reference for the first value to be
compared. IN1 must be a valid number. Constants must be
integers for double precision signed integer operations.
IN1 is on the left side of the relational equation, as in IN1 < IN2.

IN2

R, AI, AQ, constant
For INT data only: I, Q,
M, T, G

IN2 contains a constant or reference for the second value to be
compared. IN2 must be a valid number. Constants must be
integers for double precision signed integer operations.
IN2 is on the right side of the relational equation, as in IN1 <
IN2.

flow, none

Output Q is energized when IN1 and IN2 match the specified
relation.

Example

In the example, two double precision signed integers are tested for equality. When the relay
%I0001 passes power flow to the LE (Less or Equal) function, the value presently in the
reference nicknamed PWR_MDE is compared to the value presently in the reference
BIN_FUL. If the value in PWR_MDE is less than or equal to the value in BIN_FUL, coil %Q0002
is turned on.

Figure 314

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23.6.3

Relational Functions Range

The Range function determines if a value is within the range of two numbers.

Data Types for the Range Function

The Range function operates on these types of data:

INT

Signed integer (default).

DINT

Double precision signed integer.

WORD

Word data type.

When the Range function is enabled, it compares the value of input IN against the range
specified by limits L1 and L2. Either L1 or L2 can be the high or low limit. When the value is
within the range specified by L1 and L2, inclusive, output parameter Q is set ON (1).
Otherwise, Q is set OFF (0).

Figure 315

Parameters for the Range Function

Input/
Output

Choices

Description

enable

flow

When the function is enabled, the operation is performed.

R, AI, AQ, constant
INT and WORD only: I, Q,
M, T, G

L1 contains the start point of the range.
Constants must be integer values for double precision
signed integer operations.

R, AI, AQ, constant
INT and WORD only: I, Q,
M, T, G

L2 contains the end point of the range.
Constants must be integer values for double precision
signed integer operations.

R, AI, AQ
INT and WORD only: I, Q,
M, T, G

IN contains the value to be compared against the range
specified by L1 and L2.

flow, none

Output Q is energized when the value in IN is within the
range specified by L1 and L2, inclusive.

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Example

In this example, when the Range function receives power flow from relay %I0001, the
function determines whether the value in %AI001 is within the range 0 to 100.

%R0001 contains the value 100. %R2 contains the value 0.

Figure 316

Output coil %Q0001 is On only if the value presently in %AI0001 is within the range 0 to 100.

IN Value %AI001

Q State %Q0001

< 0

OFF

—

100

> 100

OFF

23.7

Relay Functions

Normally Open Contact

–

| |

–

Normally Closed Contact

–

|/|

–

Normally Open Coil

–

( )

–

Retentive SET Coil

–

(SM)

–

Retentive RESET Coil

–

(RM)

–

Negated Retentive Coil

–

(/M)

–

Negated Coil

–

(/)

–

Retentive Coil

–

(M)

–

SET Coil

–

(S)

–

RESET Coil

–

(R)

–

Positive Transition Coil

–

(



)

–

Negative Transition Coil

–

(



)

–

Vertical Link vert

Horizontal Link horz

–

Continuation Coil

–––

<+>

Continuation Contact

<+>

–––

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Each relay contact and coil has one input and one output. Together, they provide logic
flow through the contact or coil.

Input

→

----| |----



Output

23.7.1

Relay Functions Normally open, Normally-closed,
Continuation Contacts

A contact is used to monitor the state of a reference. Whether the contact passes power
flow depends on the state or status of the reference being monitored and on the contact
type. A reference is ON if its state is 1; it is OFF if its state is 0.

Type of Contact

Display

Contact Passes Power to Right:

Normally Open

-| |-

When reference is ON.

Normally Closed

-|/|-

When reference is OFF.

Continuation Contact

<+>---

If the preceding continuation coil is set ON.

Normally Open Contact -| |-

A normally open contact acts as a switch that passes power flow if the associated reference
is ON (1).

Normally Closed Contact -|/|-

A normally closed contact acts as a switch that passes power flow if the associated
reference is OFF (0).

Example

The example shows a rung with 10 elements having nicknames from E1 to E10. Coil E10 is
ON when reference E1, E2, E5, E6, and E9 are ON and references E3, E4, E7, and E8 are OFF.

Figure 317

Continuation Coils and Contacts

Continuation coils and continuation contacts are used to continue relay ladder rung logic
beyond the last column. The state of the last executed continuation coil is the flow state
used on the next executed continuation contact. If the flow of logic does not execute a
continuation coil before it executes a continuation contact, the state of the contact is no
flow. There can be only one continuation coil and contact per rung; the continuation contact
must be in column 1, and the continuation coil must be in the last column.

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23.7.2

Relay Functions Coils

Coils are used to control discrete references. Conditional logic must be used to control the
flow of power to a coil. Coils cause action directly; they do not pass power flow to the right.
If additional logic in the program should be executed as a result of the coil condition, an
internal reference for the coil, or a continuation coil/contact combination may be used.

Coils are always located at the rightmost position of a line of logic:

Figure 318

References and Coil Checking

When the level of coil checking is set to “single”, you can use a specific %M or %Q reference

with only one Coil, but you can use it with one Set Coil and one Reset Coil simultaneously.

When the level of coil checking is “warn multiple” or “multiple”, each reference can be used

with multiple Coils, Set Coils, and Reset Coils. With multiple usage, a reference could be
turned On by either a Set Coil or a normal Coil and could be turned Off by a Reset Coil or by
a normal Coil.

Power Flow and Retentiveness

The following table summarizes how power flow to different types of coils affects their
reference. The states of retentive coils are saved when power is cycled or when the PLC goes
from Stop to Run mode. The states of non-retentive coils are set to zero when power is
cycled, or the PLC goes from Stop to Run mode.

Type of Coil

Symbol

Power to Coil

Result

Normally Open -( )-

ON
OFF

Sets reference ON, non-retentive.
Sets reference OFF, non-retentive.

Negated

-(/)-

ON
OFF

Sets reference OFF, non-retentive.
Sets reference ON, non-retentive.

Retentive

-(M)-

ON
OFF

Sets reference ON, retentive.
Sets reference OFF, retentive.

Negated
Retentive

-(/M)-

ON
OFF

Sets reference OFF, retentive.
Sets reference ON, retentive.

Positive
Transition

-(P)-

OFF to ON

If power flow into the coil was OFF the previous
sweep and is On this sweep, sets the coil ON.

Negative
Transition

-(N)-

ON to OFF

If power flow into the coil was ON the previous
sweep and is OFF this sweep, sets the coil ON.

SET

-(S)-

ON to OFF

Sets reference ON until reset OFF by ( R ), non-
retentive.
Does not change the coil state, non-retentive.

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Type of Coil

Symbol

Power to Coil

Result

RESET

-(R)-

ON to OFF

Sets reference OFF until set ON by (S), non-
retentive.
Does not change the coil state, non-retentive.

Retentive SET

-(SM)-

ON to OFF

Sets reference ON until reset OFF by (RM),
retentive.
Does not change the coil state.

Retentive
RESET

-(RM)-

ON to OFF

Sets reference OFF until set ON by (SM)-,
retentive.
Does not change the coil state.

Continuation
Coil

----<+>

ON
OFF

Sets next continuation contact ON.
Sets next continuation contact OFF.

A coil sets a discrete reference ON while it receives power flow. It is non-retentive; therefore,
it cannot be used with system status references (%SA, %SB, %SC, or %G).

Example

In the example, coil E3 is ON when reference E1 is ON and reference E2 is OFF.

Figure 319

Negated Coil

A negated coil sets a discrete reference ON when it does not receive power flow. It is not
retentive, so it cannot be used with system status references (%SA, %SB, %SC, or %G).

Example

In the example, coil E3 is ON when reference E1 is OFF.

Figure 320

Retentive Coil

Like a normally open coil, the retentive coil sets a discrete reference ON while it receives
power flow. The state of the retentive coil is retained across power failure. Therefore, it
cannot be used with references from strictly non-retentive memory (%T).

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Negated Retentive Coil

The negated retentive coil sets a discrete reference ON when it does not receive power flow.
The state of the negated retentive coil is retained across power failure. Therefore, it cannot
be used with references from strictly non-retentive memory (%T).

Positive Transition Coil

If the reference associated with a positive transition coil was OFF , when the coil receives
power flow it is set to ON until the next time the coil is executed. (If the rung containing the
coil is skipped on subsequent sweeps, it will remain ON.) This coil can be used as a one-shot.

Transitional coils can be used with references from either retentive or non-retentive
memory (%Q, %M, %T, %G, %SA, %SB, or %SC).

Negative Transition Coil

If the reference associated with this coil is OFF, when the coil stops receiving power flow the
reference is set to ON until the next time the coil is executed.

Transitional coils can be used with references from either retentive or non-retentive
memory (%Q, %M, %T, %G, %SA, %SB, or %SC).

Example

In the example, when reference E1 goes from OFF to ON, coils E2 and E3 receive power flow,
turning E2 ON for one logic sweep. When E2 goes from ON to OFF, power flow is removed
from E2 and E3, turning coil E3 ON for one sweep.

Figure 321

SET Coil

SET and RESET are nonretentive coils that can be used to keep (“latch”) the state of a

reference either ON or OFF. When a SET coil receives power flow, its reference stays ON
(whether or not the coil itself receives power flow) until the reference is reset by another
coil.

SET coils write an undefined result to the transition bit for the given reference.

RESET Coil

The RESET coil sets a discrete reference OFF if the coil receives power flow.  The reference
remains OFF until the reference is set by another coil.  The last-solved SET coil or RESET coil
of a pair takes precedence.

RESET coils write an undefined result to the transition bit for the given reference.

EMERSON PACSystems VersaMax MICRO PLC & NANO PLC. USER MANUAL (2019) - page 32