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Figure 17 - Magnetic Reed Switch
Activation
It is necessary to calibrate the UNI-TRAN Premium Plus when it is used as a stand-alone device and connected
to other monitoring equipment requiring a precise 4 to 20mA output signal. The following calibration
procedure should be followed to ensure an accurate correlation between the 4 to 20mA output signal and
the sensor input signal.
Calibration Procedure for UNI-TRAN Premium Plus (not applicable for ST1400 O2 sensor, refer to the
end of this procedure)
< Confirm that the system is powered-up and is not indicating a fault; Status LED is showing a
green blip every 2.0 seconds.
< Ensure that the sensor is in a clean air environment before beginning the calibration procedure or
we recommended to flow certified ZERO AIR at a rate of 0.5 litres per minute through the
barbed tubing connector on the end of the sensor calibration cup accessory, for one minute to
ensure clean air is present. If the input device is another transmitter be sure that it is calibrated
and that the input to the Toxic Detector is 4.0mA.
< Enter the main menu by activating the magnetic reed switch
or manual push button switch. When the countdown from 10
to 0 is complete remove the magnet from the magnetic reed
switch or release the CAL/RESET push button. When
prompted with Calibrate sensor “YES?” select the function
by momentarily placing the magnet on the reed switch or
depressing the CAL/RESET button. The selection is
acknowledged with flashing “YES”. The controller starts
calibration. The following Instructions are scrolled across the
display for calibration:
Setting Zero - At this time input should be 4.0mA or ZERO gas
applied to the sensor (3.0mA output current level).
Apply 50 % Span - at this time input should be 12.0mA or apply 50%
span gas at a rate of 0.5 litres per minute to the end of the sensor
calibration cup accessory (3.3mA output current level).
Setting Span - increasing input signal has been detected (3.3mA output current level).
Remove Gas - at this time input should be reduced to 4.0mA by removing span gas from the sensor (3.6mA
output current level).
Cal Complete - Returns to normal operation (4.0mA output current)
NOTE:
If span setting does not complete successfully within ten minutes of starting the calibration
sequence the status LED alternates flashes of RED and GREEN, the analog output changes
back and forth from 3.0 to 3.3mA and Fail Cal. message is displayed on the screen. The unit
remains in this state until acknowledged by a manual Reset. After manual Reset the program
will return to the normal operation mode using previous calibration values. Since the
calibration was unsuccessful another attempt may be made or replace the sensor and re-try
calibration.