Vega DSGH, Operating Instructions Manual

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DSGH Installation and Operation Guide 75
Diagnostics and repair
Analog alarm
If the current loop output (analog output) is stable at 2 mA or 22 mA, the
analog alarm is set.
The analog alarm is set when the counts from the detector fall below a set
threshold, indicating that the detector is not outputting enough counts to
make a meaningful measurement. This is known as 0 counts.
If the analog alarm is on, verify:

Source holder shutter is in the On or Open position to create the
required radiation field.

Extreme build-up on walls or other material shielding the detector from
the radiation field.

Damage or disconnection of electrical connections from the sensor
assembly to the CPU board.
Process alarm
This alarm alerts users when the process density is above (high limit) or
below (low limit) a setpoint. Enter the choice of low or high limit and the
setpoint on the
Alarm | Relay Setup tab.
This alarm works only with the output relay. HART messages, gauge status
diagnostics, and history information are not saved for this alarm.
The gauge acknowledges or resets the process alarm when the process
value returns to the setpoint value. Depending on your usage of the process
alarm relay, you may install a process alarm override switch to manually
turn off an annunciator when the gauge relay energizes.
X-ray alarm
This alarm compensates for falsely indicated process values that occur
when the gauge detects external radiographic sources (example: vessel
weld inspections often use portable radiographic (x-ray) sources). X-rays
that the gauge detects can cause a false low reading and adversely affect
any control based on the gauge output.
This alarm can:
• Alter the current loop output to indicate the alarm condition