MSA SUPREMA - Page 190

REV 0, June 2005Page 190
Operation Manual SUPREMA
7. Maintenance and Service
In the following section, the procedure for checking and correcting the display for active sensors
is described.
Checking and Adjusting the Display
If, in spite of correctly calibrated active sensors, the expected values (0% of the measuring
range for a signal current of 4 mA and 100 % of the measuring range for a signal current of 20
mA) do not appear on the SUPREMA, the calibration on the SUPREMA must be checked and
corrected if necessary.
For this purpose, either the signal current of the connected sensor or a variable power source
can be used. If the signal current of the sensor is used, make sure that the sensor is supplying
the correct values.
Tip: A simple way to correct a possibly incorrectly set measure point consists in
changing the selected type of sensor in the “Setup/Measure Points/Sensor Data”
menu. To do this, navigate to the “Setup/Measure Points/Sensor Data” menu, select
any other type of sensor, and confirm the selection ([OK] field in the “Setup/Measure
Points/Information” menu). Then re-select the type of sensor actually connected
and confirm. The measure point will thus be set back again to the standard setting
of 4 mA = 0 % of the measuring range and 20 mA = 100 % of the measuring range.
Attention: The measure point should be locked during this adjustment (to prevent
an alarm from being triggered).
Note: During this calibration the measuring point must be inhibit (alarm rejection).
Note: No adjustments on the MAI module are either necessary or possible for active
sensors.
Calibration with a Variable Power Source
One person is required for this procedure. The following steps are to be performed:
• Lock the measure point in question in the “Setup/Measure points” menu to prevent an
alarm from being triggered.
• Then detach the cable connections of the sensor to the MAT module.
• Connect the variable power source to the MAT module as follows:
MAT module terminal 1: + pole of the power source (signal)
MAT module terminal 4: – pole of the power source (GND)
• Set the output current of the power source to 4 mA.
• Unlock the measure point in question in the “Setup/Measure Points” menu to allow a
calibration.
• Select the “Maintain/Calibration” menu.
• Select the measure point to be calibrated in the “Measure Point” field.
• Enter 0 % of the measuring range in the field “Zero Gas” as the zero gasconcentration.