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Standard Programming

The standard programming configuration, illustrated in figure 1, shows that references for voltage, current, voltage trip, and current trip are established by internal 2 mA current sources producing voltages across potentiometers RV, RI, RTV, and RTI. These potentiometers are the front panel controls for voltage, current, voltage trip, and current trip, respectively.

Resistors placed in series with the voltage and current trip potentiometers allow settings above the maximum voltage and current of the power supply.

Figure 1. Standard programming configuration using internal potentiometers

Remote Programming

PQ series supplies allow voltage, current, voltage trip, and current trip to be programmed from a remote location. Programming can be accomplished either by resistive, voltage, or current programming circuits.

Figure 2 illustrates the three alternatives for programming output voltage. The method applies equally to programming an output current, voltage trip, and current trip.

Resistive Programming

Resistive programming requires setting position 2 of S2 to 0 and connection of an external potentiometer or resistor between terminals 20 and 4 of JO2. Like the internal voltage potentiometer, the 2 mA reference produces a voltage across the potentiometer or resistor which is used to set the output voltage. A metal film resistor or wire wound potentiometer will result in the lowest temperature coefficient.

To program an output current, voltage trip, or current trip, use the same method and refer to manual for terminal identification.

The expressions for programming output voltage, V_O, output current, I_O, voltage trip, T_V, and current trip, T_I are given as follows:

Figure 2. External (a) resistive, (b) voltage, and (c) current programming