Service manual

89
Current Programming (Figure A-7).
Check switches A1 and A2 on the rear panel, they must be in the correct positions
for CV and CC current programming (See Figure A-2). A current sink variable from 0 to 2mA, can be used to program the
output voltage or current from 0 to full scale (See Figure A-7). The following paragraph provides a brief circuit description,
refer to schematic diagram.
Figure A-7. Current Programming of Output Voltage and Current
To program voltage, the current sink can be connected from J3-21 (CV CURRENT PROG) to J3-20 ( -15V). To program
current, the current sink can be connected from J3-2 (CC CURRENT PROG) to J3-20 ( -15V). Current sinks can either be
connected to the power supply ( -15V) or to an external negative supply that is referenced to the L. COMMON of the power
supply.
The 0 to 2mA current sink will cause the output signal of op-amps U17 and U18 to vary proportionally from 0 to 5 volts.
These signals are then coupled through relays K1 and K2 and then on to the A2 Board's CV and CC circuits which, in-turn,
will program the supply's output from 0 to full scale. If the programming lines become open circuited (user's system
becomes disconnected from J3) during current programming, the Programming Protection circuit will bring the power
supply output to zero.
Remote Monitoring
The 002 Option board provides a protected 0 to 5V output corresponding to a full scale voltage output. The voltage monitor
output is available between pins J3-5 (V. Monitor) and J3-1 (D COMMON).
Observe the caution described in Local Programming paragraph, page 85 (Figure A-3).