Programming chapter 3 – Rockwell Automation 1771-PD PID MODULE (+DU) User Manual

Page 73

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Programming

Chapter 3

3Ć30

Figure 3.8

Expanded Control Word, Loop 1 W30 and Loop 2 W50

1

0

Loop 1

1

0

17

16

15

14

13

12

11

10

07

06

05

04

03

02

01

00

1

0

1

0

W30

Loop 2

W50

FFI1

FFI2

Note: If you change a loop 1 or loop 2

parameter, you must initiate a load/enter sequence

SCALE

PV1

SCALE

PV2

SCALE

SP1

SCALE

SP2

SCALE

ERROR1

SCALE

ERROR2

DECOUPLE

0

TIEBACK

FFI1

PC

TIEBACK

FFI2

PC

NEG.

FFI1

POS.

NEG.

FFI2

POS.

[FFI+FF0]

[FFI+FF0]

MULTIPLIER

FOR

MULTIPLIER

FOR

LEAD/LAG

LEAD/LAG

(-)

SMIN1

(+)

(-)

SMIN2

(+)

(-)

(+)

(-)

SMAX2

(+)

SMAX1

PC

PID

BIAS1

PC

PID

BIAS2

NEG.

POS.

BIAS1

NEG.

POS.

BIAS2

CASCADE

LP1 TO
SP LP2

0

W30(W50) B07,06

Multiplier for K

F

34(W54)

0 0 K

F

x1

0 1 K

F

/10

1 0 K

F

x10

1 1 K

F

x100

W30(W50) B05

1=Enabel lead/lag W35,36 (W55,W56)

0=No lead/lag

W30(W50) B04

1=Negative value for SMIN W31(W51)

0=Positive value for SMIN

W30(W50) B03

1=Negative value for SMAX W32(W52)

0=Positive value for SMAX

W30(W50) B02

1=Set BIAS from PC Processor W08(W15)

0=PID Algorithm BIAS(FFV)

W30(W50) B01

1=Change sign of BIAS(FFV)

0=Maintain sign

W30 B00

1=Cascade Loop 1 into Loop 2 (in W30 only)

0=No cascade (Set W50 B00=0)

W30(W50) B17

1=Use scaling for PV W65

0=No scaling, nonĆscaled value returned

W30(W50) B16

1=Use scaling for SP W06(W13)

0=No scaling, nonĆscaled value returned

W30(W50) B15

1=Use scaling for ERROR W62

0=No scaling, nonĆscaled value returned

W30(W50) B14

1=Decouple Loop 1 to Loop 2 in W30, only

0=No decoupling (Set W50 B14=0)

W30(W50) B13

1=FFI from hardware Tieback input

0=FFI from PC Processor W10(W17)

W30(W50) B12

1=Change FFI to a negative value

0=Maintain FFI as a positive value

W30(W50) B11

1=Perform square root FFI

0=No square root

W30(W50) B10

1=Multiply FF term by K

F

0=No multiplication

11111

K

F

I X

K

F

2 X

K

F

I

K

F

I

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