FC 110 - Ladder Logic Rung (5 Input)

Function code 110 implements a rung of a Ladder logic program (relay type). It accepts five boolean input signals and performs a fundamental operation on each input in sequential order. After each input is operated on, the resulting value goes to the top of the stack. The output of the rung block is the value on the top of the stack unless S1 forces it to another value.

 

Outputs:

Blk

Type

Description

N

R

Output value determined by S1 and value on top of stack

If S1 = 0, output = value on top of stack

If S1 = 1, output = previous value of output

If S1 = 2, output = logic 0

If S1 = 3, output = logic 1

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

Y

0

I

0 - 3

Output descriptor:

0 = normal

1 = hold previous value

2 = force output to logic 0

3 = force output to logic 1

S2

Y

0

I

0 - 242

Operation performed on input 1

S3

Y

0

I

0 - 242

Operation performed on input 2

S4

Y

0

I

0 - 242

Operation performed on input 3

S5

Y

0

I

0 - 242

Operation performed on input 4

S6

Y

0

I

0 - 242

Operation performed on input 5

S7

N

0

I

Note 1

Block Address of Input 1

S8

N

0

I

Note 1

Block Address of Input 2

S9

N

0

I

Note 1

Block Address of Input 3

S10

N

0

I

Note 1

Block Address of Input 4

S11

N

0

I

Note 1

Block Address of Input 5

 

NOTES:

1. Maximum values are: 9,998 for the BRC-100 , IMMFP11/12 and 31,998 for the HAC

 

 

110.1   Explanation

 

This block accepts five boolean inputs, performs a specified fundamental operation on each input in turn, and provides an output dependent on the results of the operations and the output mode selected with S1.

 

The controller takes a Ladder program entered on a human system interface (HSI) and translates it to a group of rung

blocks internally. Any changes made to the Ladder program after the conversion are easily saved by downloading them to the controller. This insures that all information is in the proper format when it is processed.

 

The function code the rung is translated to depends on the number of inputs to the rung. This is automatically defined in the Harmony controllers by the PC90 Ladder programmer. Figures 110-1 and 110-2 illustrate how to use the rung function codes (110, 111, 112) without the PC90 Ladder programmer.

 

AND, OR and PUT operations are performed sequentially on inputs one through five as specified with S2 through S6. The PUT operation places the specified value on top of a stack of values. The result of the most current operation always goes to the top of the stack. The value resulting from operation one is placed on a stack that has an initial value of one in the harmony controllers. Operation two is then performed, and the resulting value becomes the value on top of the stack, and so on through operation five. Once all operations have been performed, the controller reads S1 to determine the output value. If it is zero, the value from the top of the stack (the result of operation five) is the output. Otherwise, the output is overridden and forced to zero or one or held from the previous output. The value on the top of the stack reverts to the initial value at the beginning of each controller execution cycle, so the first operation should always be a PUT to insure that the operations are performed on the desired values.

 

 

110.1.1  Specifications

 

S1 - OUT

(Output descriptor) Defines the output:

0 = Normal output. The value of the output will be the value on top of the stack when all operations on inputs are complete.

1 = Hold previous output. The value of the output will be the previous output value, regardless of the value on top of the stack.

2 = Force output to logic 0. The value of the output will be logic 0 regardless of the value on top of the stack.

3 = Force output to logic 1. The value of the output will be logic 1 regardless of the value on top of the stack.

 

S2 to S6 - F1 to F5

Identify:

  1. The operation to be performed on the input.

  2. The input value the operation is performed on.

  3. The input override.

 

Specification information for S2 through S6 is in the format:

 

 

S7 to S11- IN1 to IN5

Block addresses of inputs one through five.

 

 

 

110.1.2  Outputs

 

N

Dependent on value on top of the stack and the value of S1.

• If S1 = 0, output = value on top of the stack.

• If S1 = 1, output = previous value of output, regardless of the value on top of the stack.

• If S1 = 2, output = logic 0, regardless of the value on top of the stack.

• If S1 = 3, output = logic 1, regardless of the value on top of the stack.

 

 

 

110.2   Applications

 

Figures 110-1 and 110-2 illustrate the operations the Ladder programmer performs internally. Ladder logic uses the logic states of various inputs to drive devices. Figure 110-1 is one rung of a Ladder program. Figure 110-2 is the AND/OR logic representing that rung. The specifications list shows the information entered by the operator in order to implement this logic in a controller when not using the Ladder programmer. The Ladder programmer translates the Ladder logic created by the operator directly into rung function blocks that can be downloaded to a controller.

 

 

 

 

110.2.1  Example Specifications for figures 110-1 and 110-2

 

S1 – 0

Output value on top of stack.

 

S2 – 010

No input override, use logical state of input, PUT value on top of stack.

 

S3 – 011

No input override, use logical state of input, AND with value on top of stack.

 

S4 – 012

No input override, use logical state of input, OR with value on top of stack.

 

S5 – 021

No input override, use logical state of inverted input, AND with value on top of stack.

 

S6 – 011

No input override, use logical state of inverted input, AND with value on top of stack.

 

S7

Block address of input one.

 

S8

Block address of input two.

 

S9

Block address of input three.

 

S10

Block address of input four.

 

S11

Block address of input five.

 

The circuit is complete when input five equals one and input four equals zero, and either inputs one and two, or input three

is true (Fig. 110-2).

 

NOTE: The PC90 Ladder programmer is best suited for Ladder programming type logic. Refer to the Ladder Programming (SLAD) instruction.