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Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual User Manual

Page 240

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EAF

Process Control Instructions

Chapter 16

16-29

Input Format Bit (Word 01, Bit 07)
Allows the Process Variable (PV) and Tieback (TB) to be input in Binary
or BCD (series C or later).

Reset (0)

PV and TB are in Binary

Set (1)

PV and TB are in BCD

Integral Gain (Word 05)
When using the Independent Gain Equation, this value is the integral gain
constant K

I

(rep/sec). When using the Dependent Gains Equation, this

value is equal to T

I

(min/rep).

K

I

x10(Word 02, Bit 00)

When using the Independent Gains Equation. Set this bit to move the
implied decimal point of K

I

to the right (for example 0.10 converts

to 1.00).

Reset (0)

decimal point not moved

Set (1)

decimal moved one place to the right

K

D

/10 (Word 02, Bit 01)

When using the Independent Gains equation, set this bit to move the
implied decimal point of K

D

to the left (for example, 10.0 converts to

1.00). This improves the resolution of this term.

Reset (0)

decimal point not moved

Set (1)

decimal moved one place to the left

Manual Control Station
A manual control station is a hardware device used to control the output
directly and override the PID instruction’s output. The use of a manual
control station is optional. Set Output mode allows the same features
without this hardware device (See Set Output). When using a manual
control station, feed the manually controlled output value into the PID
instruction’s tieback (TB) input. The PID instruction uses this value
(0 to 4095) to calculate the integral term value required to achieve a
bumpless transfer when switching from manual to automatic control.

Maximum Output Alarm (Word 01, Bit 11)
This bit is set by the EAF instruction whenever the computed Control
Output goes above the limit set by Maximum Control Output (word 12).

Mode (Word 01, Bit 01)
Set/reset this bit to choose either Automatic or Manual mode. A hardwired
auto/manual station would manipulate this bit.

Reset (0)

Automatic

Set (1)

Manual