RKI Instruments M2 Rig Monitor - Manual (Page 23)

M2 Rig Monitor Operator’s Manual 18
4 - 20 mA Signal Output Operation
The output at the S terminal of the power/signal terminal strip is a 4 - 20 mA signal that
corresponds to the detection range of the M2 Rig Monitor. During normal operation, this
signal tracks the gas concentration on the LCD.
There are several circumstances where the signal output will not track the display reading
but will behave as follows:
• When the Rig Monitor is in its warm-up period, the signal output will be fixed at 3.5
mA (zero).
• If you enter Calibration Mode, Configuration Mode, or Modbus Mode, the signal
output will be fixed at 3.5 mA until the Rig Monitor returns to normal operation.
• If the Rig Monitor’s input power decreases below 10 volts so that the Rig Monitor is in
a low power alarm, the signal output is fixed below 2.4 mA until the low power alarm
is cleared.
NOTE: Under typical operating conditions, there may be no low power alarm. The 12
VDC battery that is recommended for operation may fail before the power
converter recognizes a low power condition.
• If the Rig Monitor goes into a fail condition, after a 30 second delay, the signal output
is fixed below 2.4 mA until the fail alarm is cleared. During the 30 second delay, the
signal output follows the detector output. In the case of a downscale reading, the
display and the signal output continue to track the reading down to -99% of full scale
(1.15 mA).
Alarm Indications
NOTE: The M2 Rig Monitor includes alarm on and alarm off delay settings for alarm 1
and alarm 2. The alarm indications described in this section operate according
to the factory set alarm settings. See Table 4 on page 23 for all the factory
settings.
Table 3: Visual and Audible Alarm Indications
Condition Cause Visual Indication(s)
Alarm 1
1 Increasing gas reading at or above the
alarm 1 setpoint • A1 LED is on
• Gas reading alternates
with ALARM-1 message
• Strobe/horn activates
Alarm 2
1 Increasing gas reading at or above the
alarm 2 setpoint • A2 LED is on
• Gas reading alternates
with ALARM-2 message