Rockwell Automation 1771-PD PID MODULE (+DU) - Manual (Page 65)

Programming
Chapter 3
3Ć22
Table 3.D
Error Function Codes
W18(W38)
V
P
B07
V
I
B05
B06
B04 Error Function
0
0
1
1
0
1
0
1
Error
2/3 (Error) + 1/3 (Error) 2
1/3 (Error) + 2/3 (Error) 2
(Error) 2
Error|Error|
Where (Error) 2 =_________
512
W18 (W38) B02 Maximum Derivative Term Limit. Reset to 0
inhibits derivative term limiting. Set to 1 the value of the derivative
term VD is limited to the maximum value VD MAX in word W27
(W47). This limit applies to both negative and positive excursions of
the derivative term VD.
W18 (W38) B01 Hold PID Calculation. Reset to 0 continues the
PID algorithm calculation. Set to 1 holds the PID algorithm output
VPID at its last value. The hold is useful when turning the
feedforward portion of the loop.
W18 (38) B00 Hold Bias. Reset to 0 continues the bias calculation.
Set to 1 holds the bias at its last value. The hold is useful when
tuning the PID portion of the loop.
W19 (W39) Loop Control Word B. This word together with loop
control word A, W18 (W38), and the loop expanded control word, W30
(W50), select the configuration for the loop. Bits 17 through 00 are
defined below and summarized in Figure 3.7 for loop 1 control word B
W19, and loop 2 control word B W 39. Note that bits B11, B10, B07, and
B06 are valid only if the expanded loop feature has been selected by W01
B14 = 1.
W 19 (W39) B17 VPID +/xBias. Reset to 0 the output is the sum V
= VPID + BIAS. Set to the output is the normalized product V =
(VPID x BIAS)/4095. The sum is normally used.
W19 (W39) B16 Output Limiting. Reset to 0 inhibits output
limiting. Set to 1 the analog output value is limited to the minimum