Sierra Monitor Corporation 2050-10 - Manual (Page 7)

2050/2060 Gas Monitors (5/04) Page:
Instruction Manual
4
3.0 OPERATION
3.1 Introduction
Under normal conditions the gas sensor module does
not require operator or technician intervention. The
following are conditions under which the module re-
quires attention:
- Routine periodic calibration
- Sensor replacement on a planned schedule
or when a sensor failure occurs.
- Periodic cleaning as necessary.
3.2 Alarms
Three alarm conditions are possible. These can be
detected visually at the optional Sierra Monitor con-
troller and at the module.
Warm-Up Alarm
Oscillating (On/Off) contact closure and “red/
green” visual indication when power is first con-
nected to the module, followed by a continuous
closure of approximately 2-60 minutes indicat-
ing warm-up.
Buzzer Relay Relay
Fail Safe
On/Off Oscilating Oscilating
Gas Alarm
Sustained contact closure and solid red light
(once the warm-up time is completed) indicat-
ing the presence of gas at, or above, the pre-set
alarm limit.
Table 2.1
Buzzer Relay Relay
Fail Safe
On Closed Open
Trouble Alarm
Interrupted contact closure and “red/green” vi-
sual indication (once the warm-up time is com-
pleted) after unit has been in operation, indicat-
ing either a failed sensor or calibration problems.
Buzzer Relay Relay
Fail Safe
On/Off Oscilating Oscilating
3.3 Outputs
For the non-relay configurations a 5 volt DC TTL
signal is provided to activate remote alarms such
as the Sierra Monitor Alarm Panels. Relay configu-
ration alarm conditions described above are trans-
mitted to the annunciator as relay contact closures
from the monitor.
The alarm outputs are non-latching closed contacts.
As soon as the gas concentration falls below the
alarm set-point, the alarm will stop and the alarm
output will cause the relay to de-energize and the
contacts will open.
During warm-up and failed sensor alarms the re-
lays contact and the display LED's oscillate at ap-
proximately one hertz.
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