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

Page 203

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Application Example 2, Periodic Block

Transfer

Appendix C

CĆ19

Bit 10 = 0

Integral output limiting is not used.

Bits 07,06 = 1

Proportional error is squared.

Bits 05,04 = 0

Integral error is squared.

Bit 03 = 0

Derivative error is not modified.

Bit 02 = 0

Derivative output is not limited.

Bit 01 = 0

PID output is not held.

Bit 00 = 0

Bias is not held.

Loop 2 Control Word B W39

Bit 17 = 0

Bias is added to the output.

Bit 16 - 0

Output limiting is not used.

Bits 15,14,13=1

If a soft fault occurs, output 2 is set to
maximum.

Bit 12 = 0

Digital filter time multiplier is x1.

Bit 11,10=0

Lead/lag time x1.

Bit 7 = 0

Set point sign is positive.

Bit 06 = 0

Setpoint multiplier is x1.

Bits 05 = 1,04=0

Proportional gain multiplier is x10

Bits 03,02=0

Integral gain multiplier is x1.

Bits 01,00=0

Derivative gain multiplier is x1.

Loop 2 Expanded Control Word W50

Bit 17 = 1

Process variable is scaled.

Bit 16 = 1

Set point is scaled.

Bit 15 = 1

Error is scaled.

Bits 14 thru 00=0

None of these features are used.

Selected feature values for this example program have been recorded in
worksheets 1,2 and 3. (figures C.4, C.5 and C.6, respectively.) Worksheet
1 represents the dynamic block (data table words 257-277

8

). The PID

module word numbers correspond to the position numbers on the display
and are numbered W01 through W17. Worksheet 2 represents the loop 1
block (data table words 300-322

8

). Worksheet 3 represents the loop 2

block (data table words 324-346

8

). The PID word numbers (position

numbers) are W18 through W36 and W38 through W56, respectively for
loop 1 and loop 2. Refer to the data table map (figure C.3) which shows
the locations of the consecutive data blocks.