Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual - Manual (Page 93)

Publication 1746-UM008B-EN-P - December 2006
Ladder Programming Examples 93
Program to Verify Configuration Word Data Changes - Continued
Interface 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.
Use this procedure to program this application.
1. Select 100
Ω Platinum RTD, ∝ = 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. Select scaled-for-PID as the data type by setting bit 4 = 0 and bit
5 = 1 in the configuration word.
Rung 2:4
EQUAL
Source A
N7:1
Source B 0
Check that the configuration written to channel 2 is
being echoed back in channel 2's status word.
EQU
( )
B3
3
Data valid
Rung 2:5
END
ATTENTION
When using the module’s scaled-for-PID data format with the
SLC PID function, verify that the PID instruction parameters
Maximum Scaled S
max
(word 8) and Minimum Scaled S
min
(word 8) match the module’s minimum and maximum scaled
range in engineering units, (-200…850 °C, (-328…1562 °F)) for
that channel. This allows you to accurately enter the setpoint in
engineering units (°C, °F).