b. Place the Computer-Manual switch in the COMPUTER position.
c. Set the voltage limit potentiometer to 10.
d. Energize the programmer and power supply.
CAUTION:
Always energize the programmer first, then the
power supply upon system startup and always deenergize the
programmer last on system shutdown to allow the programmer to
always have control of the system. Not doing so could result in
voltage/current spikes introduced in the magnet system with could
produce undesirable results.
e. Enable the quench detection circuit (if desired).
f. Set the ramp rate RANGE switch to the correct rate. Note that the computer does not
control this switch. It must be set manually.
g. The programmer is now under computer control. To control the magnet current the
computer must furnish analog signals (0-5 volts) to the Ramp Rate connections (J5
Pins 1 & 14) and the Current Limit connections (J5 Pins 2 & 15). Five volts on the
ramp rate pins produces 0.1, 1.0, or 10.0 A/S depending on the setting of the ramp rate
range switch on the programmer. Five volts on the current limit pins will set the
current limit to full scale current for the system. Intermediate voltages produce scaled
values for the ramp rate and current limit. In this mode the external Up/Down/Pause
switch is inoperative because it has been disconnected internally and placed in the
"up" mode. This means that the magnet current always ramps up or down to the value
corresponding to the voltage signal from the computer. An opto-isolator signal is
available from the programmer (pins 5 & 18) which can be read to indicate when the
current limit has been reached. An analog voltage is supplied by the programmer (0-5
volts, Pins 19 & 7) which can be read directly by the computer to indicate the current
at any time. One can approximate any current function within the range of the
magnet/power supply system by a sequence of straight lines controlled by the
computer supplied ramp rate voltage and current limit voltage.
4.
Mode C
(internal ramp generator function) operation:
a. Set up the programmer and power supply as described for mode A operation.
b. Disconnect jumper W2 on the printed circuit board.
c. A linear ramp voltage controlled by the ramp range switch, the variable ramp rate
potentiometer, and the Up/Down/Pause switch is available between the green RAMP
OUT and the black COMMON terminals on the rear panel of the programmer.
d. If your magnet is equipped with a persistent switch be sure that the persistent switch
heater power supply is turned on to charge the magnet.
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