Ultima MOS-5 Detector
23
integrity of the analog connection. The DDL is available at the HART foundation’s website
(http://www.hartcomm2.org/index.html). If the Ultima MOS-5 Intelligent Sensor is ordered with
the HART option it is in the enabled state. The HART function can also be disabled and then
Channel 2 can be used for Modbus.
The Ultima MOS-5 Intelligent Sensor HART configuration is compatible with the Emerson 375
Field Communicator and AMS Aware. http://www.emersonprocess.com/
http://www.emersonprocess.com/ams/
4.6 Gas Check Mode
The sensor’s response can be checked without activating external alarms by placing the Ultima
MOS-5 Intelligent Sensor in Gas Check Mode. In this mode, the alarm relays are inhibited and
the analog output is fixed at 1.5 mA. Please see section 9.3.3 for more information on the
analog output values.
NOTE
: If HART is enabled, the current may be different. See HART analog output selection
chart.
4.6.1 Procedure for Checking the Calibration
Place the magnet over the MSA logo on the cover of the Ultima MOS-5 Intelligent Sensor.
Remove the magnet when a flashing pair of bars, “
- -
” appears on the display (about 10
seconds) (Figure 13). Apply the test gas to the sensor. The value of the gas concentration will
be indicated by the flashing display and should stabilize in 1 to 2 minutes.
Figure 13: Gas Check
When the reading has stabilized and the test is complete, remove the gas and the unit will
return to normal operation, when the concentration drops below 5% full-scale.
If, after the reading has stabilized, the sensor is to be calibrated, simply apply the magnet to the
MSA logo on the housing cover and the unit will enter Calibration Mode.
Gas Check Mode can be aborted if gas has not been applied to the sensor. Simply reapply the
magnet to the MSA logo on the cover and the unit will return to normal operation.
NOTE:
The test gas concentration must be at least 10% full-scale before the unit will complete
the gas check sequence. If the Ultima MOS-5 Intelligent Sensor is placed in the gas
check mode and no gas is applied for twelve minutes, the unit will revert to a Fault
condition. Re-applying the magnet over the MSA logo will return the unit to normal
operation.
