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5. System diagnostics
Univox PLS-X series has a built-in system test. We recommend that this feature is used
periodically, at least monthly, to check the integrity of the loop driver, its inputs and the
loop condition.
To access the system diagnostics mode, set the switch on the front panel to the right.
All the inputs are now disabled and an internal 1kHz oscillator is connected to the input
instead. The oscillator pulses at 2 seconds intervals with a 0dB level, activating the AGC
regardless of the adjusted sensitivity. The red LED indicator is flashing with the signal.
If the input level LEDs and at least one output loop current LED flash in unison, the system
is working correctly.
If the input and output LEDs do not flash, check that the loop is connected and not open circuit.
Also check the proper connection of the signal source.
If only the input LEDs flash, and the loop is properly connected, the output current is set
too low. Increase the output current.
6. Loop current control
The loop current can be adjusted by turning the loop current control (6) potentiometer.
7. Loop current LEDs
The current output level is indicated by the loop current LEDs in 3dB increments. The LED
dB scale is relative to the loop output current and is based on the available current of
the particular model. 0dB is lit when the output current is 1/4 of the maximum available
current and the power is 1/8 of the available power. Each 3dB increment represents a
doubling of the output. However, the only way to set the output level to the correct IEC
level is to use a professional field strength meter, preferably Univox FSM 2.0.
