System Alarms; Alarm Switching Logic (Default) - Michell Instruments Easidew Online User Manual

Easidew Online User's Manual
3.3

System Alarms

3.3.1

Alarm Switching Logic (Default)

The Easidew Online system has two alarm outputs. As supplied, the default alarm set-
points and the alarm switching logic are as follows (the default temperature units are
degrees Celsius):
Low Alarm -
High Alarm -
Alarm 1 (Low Alarm) is set-up to switch
(gas drier) than the alarm set-point value. For the default set-points therefore, the
default switching logic for these alarms is as follows:
Alarm 1
Alarm 2 (High Alarm) is set to switch
wetter) than its set-point value. For the default set-points therefore, the operation of
this alarm would be as follows:
Alarm 2
Depending upon the application, if required, it is possible to reverse the switching logic
for either or both of the alarm channel outputs to provide the following alarm output
confi gurations:
Alarm 1
Alarm 2
Section 3.3.2 describes the method for reversing the default switching logic and Section
3.3.3 describes the method for setting up individual alarm set-points.
Michell Instruments
Alarm 1 ( ) set to -20°Cdp
AL1
Alarm 2 ( ) set to -40°Cdp
AL2
Temp < -20 Alarm 1 = ON
Temp > -20 Alarm 1 = OFF
ON
Temp < -40 Alarm 2 = OFF
Temp > -40 Alarm 2 = ON
Temp < -20 Alarm 1 = OFF
Temp > -20 Alarm 1 = ON
Temp < -40 Alarm 2 = ON
Temp > -40 Alarm 2 = OFF
when the temperature reading is lower
ON
when the temperature reading is higher (gas
OPERATION
27