User Manual Owner's manual
Table Of Contents
- 1772-6.5.8, Mini-PLC-2/02, -2/16, -2/17 Processor, User Manual
- Important User Information
- Summary of Changes
- Table of Contents
- 1 - Using This Manual
- 2 - Fundamentals of a Programmable Controller
- 3 - Hardware Features
- 4 - Installing Your Programmable Controller
- 5 - Starting Your Processor
- 6 - Maintaining and Troubleshooting Your Processor
- 7 - Memory Organization
- 8 - Scan Theory
- 9 - Relay-Like Instructions
- 10 - Program Control Instructions
- 11 - Timers and Counters
- 12 - Data Manipulation and Compare Instructions
- 13 - Three-Digit Math Instructions
- 14 - EAF Math Instructions
- 15 - EAF Log, Trig, and FIFO Instructions
- 16 - EAF Process Control Instructions
- 17 - Jump Instructions and Subroutines
- 18 - Block Transfer
- 19 - Data Transfer Instructions
- 20 - Bit Shift Registers
- 21 - Sequencers
- 22 - Selectable Timer Interrupts
- 23 - Report Generation
- 24 - Program Editing
- 25 - Programming Techniques
- 26 - Program Troubleshooting
- A - Specifications
- B - Processor Comparison Chart
- C - Number Systems
- D - Glossary
- E - Quick Reference
- Index
- Back Cover
EAF
Process Control Instructions
Chapter 16
16-28
Feedforward or Bias (Word 07)
This input is added to the calculated control output of the PID equation. It
is used when a bias is needed or if feedforward control is desired. This
value can be a storage constant or a calculated variable of
process measurement.
Proportional only control will give a steady-state offset of the process
variable from setpoint. A bias value can be added into the control output
using this word to bring the process variable to the set point.
The feedforward value (Figure 16.9) represents a measured feed system
disturbance fed into the PID equation. Its effect is to adjust the output
before the disturbance has a chance to change the process variable, thereby
reducing the impact of the disturbance on the system.
Figure 16.9
This
Is an Example of Feedforward Control
PID
Equation
Flow
P
V
Level
Detector
CO
Σ
SP
Σ
FT
Transmitter
10374-I
Feedforward/Bias Sign Bit (Word 02, Bit 02)
Set/reset this bit to change the sign of the feedforward value.
Reset (0) value is positive
Set (1) value is negative