Michell Instruments Easidew Online, Руководство пользователя

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Easidew Online User’s Manual
Michell Instruments 27
OPERATION
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 - Alarm 1 (
AL1
) set to -20°Cdp
High Alarm - Alarm 2 (
AL2
) set to -40°Cdp
Alarm 1 (Low Alarm) is set-up to switch
ON
when the temperature reading is lower
(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 Temp < -20 Alarm 1 = ON
Temp > -20 Alarm 1 = OFF
Alarm 2 (High Alarm) is set to switch
ON
when the temperature reading is higher (gas
wetter) than its set-point value. For the default set-points therefore, the operation of
this alarm would be as follows:
Alarm 2 Temp < -40 Alarm 2 = OFF
Temp > -40 Alarm 2 = ON
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
con fi gurations:
Alarm 1 Temp < -20 Alarm 1 = OFF
Temp > -20 Alarm 1 = ON
Alarm 2 Temp < -40 Alarm 2 = ON
Temp > -40 Alarm 2 = OFF
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.