TTI PL Serie Manuel D'instructions page 12

Additional Instructions for Quad Mode Triple Versions
The Quad-Mode Triple consists of a Quad-Mode Dual as described in the previous section, plus a
logic supply.
P310QMT Logic Supply
This has a fixed 5V 1·5A output which is isolated from the other supplies.
The logic supply is protected against short circuits. It is protected against external forward
voltages up to 16 Volts and reverse voltages by a diode: the reverse current must not exceed 3
Amps.
PL320QMT & PL330QMT Logic Supply
Setting the Output
Set the output with the calibrated control. With the output switch OFF the meter (PL330 only)
displays voltage; with the switch ON it displays load current. Unless remote sensing is required
the shorting bars should be placed from + sense to + output and from - sense to - output.
Current Limit (PL320QMT)
Current limit is indicated by lighting the CURRENT LIMIT LED and is set by a calibrated control
with a range of 0·1A to 4A. The power supply is not designed to operate in constant current mode
as a current source.
Current Limit (PL330QMT)
Current limit is indicated by all the decimal points flashing and is set by a calibrated control with a
range of 0·1A to 7A. The power supply is not designed to operate in constant current mode as a
current source.
Protection
Over-voltage protection is fitted to this supply and will be triggered if the voltage across the output
terminals exceeds 7 Volts. If this occurs the power supply output is crowbared by a thyristor; the
power supply will then shut down and TRIP will be shown in the display. The power supply can be
reset by turning off the DC output switch or by turning the supply off.
The power supply is protected from reverse voltages by a diode; the reverse current must not
exceed 3 Amps.
General
Connection to the Load
The load should be connected to the positive (red) and negative (black) terminals marked
OUTPUT. Both are fully floating and either can be connected to ground. The negative terminals
are permanently connected to the power supply output, whilst the positive ones are switched
electromechanically (main outputs) or electronically (logic outputs). The green terminal is
connected to chassis and to the earth (ground) of the AC input cable.
If the unit is to be used with live measuring or load circuits which have protective earth terminals,
ensure that all protective earth terminals are connected to a protective conductor prior to
switching on (the green front panel terminal may be used for this purpose).
If the unit is to be used with live measuring or load circuits which do not have protective earth
terminals, ensure that the unit AC line plug is inserted before making connections between the
unit output terminals and such circuits.
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