Bacharach MGS-150, Installation And Operation Manual, Page: 21 / 36

MGS-150 Manual
6309-9000 Rev 2 21
Section 4. Operation and Stabilization
On powering up, the MGS-150 will sense for the presence of gas after an
initial warm-up delay of 5 minutes. The green LED will flash at 1 second
intervals during the warm-up.
In an alarm condition:
• green LED stays on and the red LED is on
• audible alarm operates (if not disabled and after delay, if set).
• relay output activates (after a delay, if set)
• V and I output changes proportionally with gas concentration.
In a fault condition:
• green LED will be off and the red LED will be on
• voltage or current fault output will activate:
o
2mA on the 4-20mA output
o
0.5V on the 1-5V output
o
1.0V on the 2-10V output.
The typical time for various sensor types to stabilize is shown below.
Sensor Type Stabilization Time
Electrochemical (EC) 20-30 seconds
Semiconductor (SC) 1-3 minutes
Infrared (IR) 2 minutes
On power up, the electrochemical sensor outputs a signal voltage
normally below the set alarm level. Semiconductors output over the +
max scale, i.e., > 5V. Both move towards zero as they stabilize.
If sensors have been in long-term storage or the detectors have been
turned off for a long period, stabilization is much slower. However, within
1-2 hours sensors should have dropped below the alarm level and be
operational. You can monitor progress exactly by monitoring the 0-10V
output. When the output settles around zero the sensor is stabilized. In
exceptional circumstances the process can take up to 24 hours or more.