Initial Operation; External Control; Computer Control - GMW 231HC User Manual

Bipolar current amplifier
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4.2 - Initial Operational Testing
Once the 231HC system is connected it is time to perform initial system operational checks.
Start by switching on the auxiliary power supply in the 231HC. The switch is in the power entry
module at the rear of the unit.
At this point the 'Auxiliary Power' LED in the status panel
should illuminate.
The 'Magnet Fault' LED should be off, if it is not check that the magnet
interlocks are correctly connected and functioning.
If a system complete with computer and software was purchased, the Amplifier Control and
Monitoring software should be started now.
Please refer to the software manual for
configuration details.
The next step is to provide DC power the 231HC. Ensure that the voltage and current controls of
the SGA DC Power Supply are set to the minimum output before turning on the main power to
the DC Supply. Turn on the DC Supply and set the current output control to about 5% (about 3
turns clockwise). Next slowly bring up the Voltage control. At about 20 volts, the 'Amplifier
Power', 'Amplifier Ready' (red aspect) and the 'DC Fault' LEDs on the status panel of the
231HC will illuminate. After about 35 volts, the status panel LEDs should change to 'Amplifier
Power', 'Amplifier Ready (green aspect) and 'Output Enabled'.
Please refer to the Copley Controls manual for the 231HC Amplifier for more information if
needed.

4.3 - External Control

To use the external control option, set the 'Control Mode' switch on the rear panel to 'External'.
This disconnects the internal DAC and connects the Analog Input terminal to the amplifier
analog control input. One thing to note is that it is still possible to use the internal DaqPAD for
monitoring the 231HC even when using an external analog control signal.
Connect an analog voltage source to the Analog Input terminal. This source should be capable
of delivering voltages from -10V to +10V. The amplifier current output is proportional to the
analog control input voltage.
Take care not to exceed an instantaneous dc power dissipation in the electromagnet in excess of
4,160W when using the SGA 160/31 power supply, or 9,280W when using the SGA 160/63
power supply. If this is exceeded, the amplifier may enter a mode that draws more power than
the DC supply can provide and the DC power supply will shut down. When the DC supply
voltage drops, the amplifier enters a 'DC Fault' mode and shuts down. Once shut down, the DC
supply will recover, then the amplifier recovers, restarts and the cycle repeats. The only way to
break the cycle is to reduce analog control signal to zero.

4.4 - Computer Control

To use the external control option, set the 'Control Mode' switch on the rear panel to 'Internal'.
This connects the internal DAC and disconnects the Analog Input terminal to the amplifier
analog control input.
Start up the computer software and ensure that everything configured correctly. Please refer to
the software manual for more information.

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