Model 4802A
17
4.7 Card Test Feature
The Card Test Input is provided so that the user can access the Card Test feature
remotely. One end of a normally open SPST switch is connected to this termination and
the other end is connected to system common (see Figure 33).
To activate the Card Test feature, simply press and hold the switch. The front panel
LED’s and digital display will begin ramping up at the start of the card test. They will
continue to ramp-up for the software selectable ramp time specified by the operator (3
or 10 seconds) during the Setup Mode (see Section 5.4). Each alarm level (A1 & A2) will
trip when the alarm set point is exceeded. The analog output signal will ramp from 4 to
20mA during the test, if the active option has been selected during the Setup Mode. At
the conclusion of the Card Test, the A1 & A2 outputs will automatically reset (overriding
any latching option). A Card Test cannot be initiated if the unit is in alarm or fault or
during an LED Test.
NOTE -
There is an option that allows active outputs during a Card Test. If this option
has been selected the relays (A1 & A2) and open collector outputs are active, and will
trip during the Card Test. This can be treated as a functional test of a Zero Two System
4.8 Fault
Diagnostics
In addition to the Fault LED on the front panel, the Model 4802A provides a fault code
on the digital display whenever a fault condition occurs. The Fault Codes that can
appear on the digital display are summarized below.
4.8.1 F1- Open analog output signal
Check connections on rear terminal pins 20d & 22d.
4.8.2 F2 - Failed to complete calibration
If this fault occurs, remove the gas and allow the sensor to see clean air for at least five
minutes. Then attempt another calibration. If the second attempt fails, replace the
sensor. If this fault continues to occur after the sensor has been replaced, consult the
factory or your GMI Representative.
4.8.3 F3 - Software checksum error
This fault occurs during initial power-up of the unit. If this fault occurs, remove and
reapply power to the unit. If the fault continues to occur, replace the unit and consult the
factory or your GMI Representative.
4.8.4 F4 - Sensor connections are open or short-circuited or there is excessive
zero drift
Make sure the sensor wires are connected properly (in the field and at the rear of the
unit) and re-calibrate if necessary. If this fault continues to occur, replace the sensor.
4.8.5 F5 - Not used at this time
This code has been reserved for future use.
4.8.6 F6 - Low supply voltage
Make sure the supply voltage level at the chassis is 24Vdc.
4.8.7 F7 - EEPROM verification failure
This fault will occur if the microprocessor cannot store calibration or setup information in
the EEPROM. If this fault occurs consult the factory or your GMI Representative.