Rockwell-automation 1746-NR4 SLC RTD/Resistance Input Module User Manu Manual de usuario descargar pdf (Pagina 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

( )

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).

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Rockwell-automation 1746-NR4 SLC RTD/Resistance Input Module User Manu Manual de usuario Pagina 93