csmstr - Omega Engineering

CSPID – PID MODULE PROGRAMMING
CRIMSON USER MANUAL - MODULAR CONTROLLER
MODE
Deviation Low
Deviation High
In Band
DESCRIPTION
If the Process Value falls below the Setpoint Value by the
amount of the Alarm Value, the alarm activates. In this
mode, the alarm point tracks the Setpoint Value.
If the Process Value exceeds the Setpoint Value by the
amount of the Alarm Value, the alarm activates. In this
mode, the alarm point tracks the Setpoint Value.
If the difference between the Setpoint Value and the
Process Value is not greater than the Alarm Value, the
alarm activates.
Out of Band
If the Process Value exceeds, or falls below, the Setpoint
Value by an amount equal to the Alarm Value, the alarm
activates. In this mode, the alarm point tracks the Setpoint
Value.
• The Value property is the point at which the alarm will turn on. The alarm values
are entered as process units or degrees.
• The Hysteresis value separates the on and off points of the alarm ie. a high acting
alarm programmed to turn on at 500 with a Hysteresis of 10, will turn off when
the PV falls below 490.
• The Latching property dictates how the alarm behaves once activated. See the
Alarm Behavior Chart below for more information.
• The Standby property provides a means of preventing so called nuisance alarms
during power up. See the Alarm Behavior Chart below for more information.
ALARM BEHAVIOR CHART
LATCHING STANDBY ALARM BEHAVIOR
Alarm automatically turns on and off as the Process Value crosses in and out of
the alarm region.
The AlarmAccept bit disables alarm, regardless of the state of the process. If the
alarm condition exists, and the bit is written to a “0”, the alarm activates.
Once activated, the alarm stays active until accepted.
If the alarm condition no longer exists, writing the Alarm Accept bit to “1”
resets the alarm condition.
As long as the Alarm Accept bit is “1”, the alarm automatically turns on and off
as the Process Value crosses in and out of the alarm region.
PAGE 24
http://www.redlion.net/controller