Precision Digital PD941 - Manual (Page 39)

ConsoliDator Multi-Channel Controller Instruction Manual
39
Proportional Plus Integral
Pulse Width Modulation Mode
PWM PI Control Mode is used to
create an on/off pulse signal with a
duty cycle modulated by the
proportional integral settings. In this
mode the percentage of the relay
cycle in which the relay is in the on
state varies with relation to the
process value feedback and the PI
settings.
Alarm Setup: 1
Alarm Mode: PWM: PI Control
Feedbk Ch: [A] Flow: 1
Set Point: 12.00 GPM
Prop. Gain: 32.0 %
Int. Time: 0.1 sec / rpt
Cycle Time: 1 sec
Rly Period: 600 sec
Int. Limit: 1.0 %
Inc / Dec: Increasing
EDIT EXIT
Set Point Enter the process target.
Feedbk Ch Select an analog input to supply the feedback signal from the
system.
Prop. Gain Enter the proportional gain expressed as a percentage.
Int. Time Enter the integral time expressed as seconds per repeat.
Cycle Time Enter the PI calculation cycle time (Low number for fast-
responding systems, high number for slow-responding
systems.)
Rly Period Enter a relay period.
Int. Limit Specify the integration limit as a percentage (Limits integral
influence on the output.)
Inc / Dec Select either [Increasing] or [Decreasing].
Note: Due to the life expectancy of mechanical relays, it is strongly recommended that cycle times be as
long as possible (many minutes.) Using a cycle time of less than a few minutes can wear out a relay and
cause faulty operation.