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

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
Ω
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