Chapter 7. PID Built-In Function BlockGFK-2950C February 2018 3637.7 PID ExampleThe following PID example has a sample period of 100ms, a Kp gain of 4.00 and a Ki gain of 1.500. Theset point is stored in %R0001, the control variable is output in %AQ0002, and the process variable isreturned in %AI0003. CV Upper and CV Lower Clamps must be set, in this case to 20000 and 4000,and an optional small Dead Band of +5 and -5 is included. The 40-word reference array starts in%R0100. Normally, user parameters are set in the reference array, but %M0006 can be set tore-initialize the 14 words starting at %R0102 (word 3) from constants stored in logic (a usefultechnique).The block can be switched to Manual mode with %M1 so that the Manual Command, %R113, can beadjusted. Bits %M4 or %M5 can be used to increase or decrease %R113 and the PID CV by 1 every100ms solution. For faster manual operation, bits %M2 and %M3 can be used to add or subtract thevalue in %R2 to/from %R113 every CPU sweep. The %T1 output is on when the PID is OK.7.7.1 Reference Array Initialization using %M00006For details on the contents of the reference array, refer to Reference Array for the PID Function.Word Function Address Value3 Sample Period %R102 104 + Dead Band %R103 55 - Dead Band %R104 56 Kp %R105 4007 Kd %R106 08 Ki %R107 15009 CV Bias %R108 010 CV Upper Clamp %R109 200011 CV Lower Clamp %R110 40012 Minimum Slew Time %R111 013 Config Word %R112 014 Manual Command %R113 015 Control Word %R114 016 Internal SP %R115 0
