Changing Engineer’s Password
The passwords are present to prevent unauthorised button entry on the control panel and
whilst the user password is fixed, the ENGINEER’S password can be changed.
Using ENGINEER’S menu 33 will allow you to enter a new engineer’s password.
You are prompted to re-enter the new password again as a check and if both are the
same then this password is the new engineers password.
Calibrating Gas Sensors (see setup procedure for sensors)
16 direct 4-20mA gas sensors – source mode
Each of the external gas sensor cards has to be periodically calibrated with its sensor to
produce a 4-20mA signal to input to the Combi (see sensor data sheets C893 & C894)
This signal input to the Combi would produce a 0 to 100% of the signal range but a
further level of calibration trimming is possible at the Combi panel.
To assist in this process, ENGINEER’S menu 20 adjust 4~20mA zero/span will guide you
through the stages of calibration for these direct sensors.
The first step is to select which of the 16 sensors is to be calibrated.
Pressing SELECT (3) moves to the next step which is -
Set the maximum value expected from the sensor e.g. flam is 99.9% Pressing SELECT
(3) moves to the next step which is -
Use the UP (1) and DOWN (5) buttons to adjust the zero on the LCD
Pressing SELECT (3) moves to the next step which is -
Apply span gas and use the UP (1) and DOWN (5) buttons to change the gain until the
reading is correct on the LCD for the applied gas.
The gas values used in this case are the peak values from the sensors and this gives the
ability to apply gas to a number of sensors before returning to the Combi panel to adjust
thus allowing one engineer to set the span. In this case, the zero on these sensors
should be completed before span is performed.
This completes the calibration of the direct 4-20mA gas sensor.
64 Addressable gas sensors
Use ENGINEER'S menu 10 (addressable zero span) on the Combi to calibrate the
addressable sensors. The inhibit LED on all connected sensors will flash. Use the UP (1)
and DOWN (5) buttons to look at all sensor addresses which are being zeroed and use
the + (4) or – (2) buttons on Combi to zero the reading on each sensor.
Press the SELECT (3) button on Combi to enter the span mode which gives plenty of
time to visit each sensor. Gas each sensor with appropriate calibration span gas and
return to the Combi panel.
Use the UP (1) and DOWN (5) buttons to view each sensor address and using the + (4)
or – (2) buttons, adjust the peak sensor reading to be that of the calibration gas. Press
SELECT (3) to exit this menu when all sensors have been adjusted.
Note: peak readings are lost when exiting from this menu. Re-enter the menu and
useagain to calibrate any missed sensors.
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