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I have used the PID instruction in the SLC-500 /03 processor with success at my normal job. I am at present enrolled in community college and working with a PLC 5/10 and building a Wonderware interface to the process simulator. My task is to program 1 PID loop that has the gains and setpoint accessible via Wonderware interface. Here's the problem. In the SLC I can address the PV and control output words directly in the instruction. After playing with the PLC5 I learned I needed to use BLOCK TRANSFERS for the analog I/O, which I have done in a subroutine file. The PID resides in a 3rd file; the instruction references the integer files associated with analog input set up in the block transfer, as does the control output. When the rung is enabled the input will vary but the control output does nothing. I don’t have any documentation on the PID instruction other than the online help file in RSLOGIX5. Any help would be appreciated. I have class again this Saturday.
Thanks in advance.
tjmurf
Thanks in advance.
tjmurf