Interfacing to the pid instruction, Interfacing to the pid instruction -5 – Rockwell Automation 1746-NR8 SLC 500 RTD/Resistance Input Module User Manual User Manual

Page 77

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Publication 1746-UM003A-EN-P

Ladder Programming Examples 5-5

Figure 5.5 Program to Verify Configuration Word Data Changes

Interfacing to the PID
Instruction

The RTD module was designed to interface directly to the SLC 5/02,
SLC 5/03, SLC 5/04 and SLC 5/05 PID instruction without the need for an
intermediate scale operation. Use RTD channel data as the process variable in
the PID instruction.

To program this application, proceed as follows:

1.

1.

1.

1. Select 100

Platinum RTD,

α

= 0.003916, as the input type by setting bit

0 = 0, bit 1 = 0, bit 2 = 1 and bit 3 = 0 in the configuration word.

2.

2.

2.

2. Select scaled-for-PID as the data type by setting bit 4 = 0 and bit 5 = 1 in

the configuration word.

COP

Copy File
Source
Dest
Length

#N10:0
#O:3.0
8

First Pass

S:1

15

EQU

Equal
Source A

Source B

I:3.10
0<
O:3.2
0<

B3:0

2

END

I:1.0

0

O:3.2

8

Set up all eight NR8 configuration registers. Registers N10:0 through N10:7 must
be loaded with the appropriate configuration words prior to execution.

This rung is used to verify the configuration word after a dynamic
change. Alarm bits can also be programmed in this rung to check for
status errors.

0001

0002

0000

0003

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