GMW 5971-160, Руководство пользователя, Страница: 8 / 39

Section 4
SYSTEM DESCRIPTION
4.1 - System Description
A complete system would typically consist of an appropriate SGA series DC power supply, the
GMW 5971-160 Reversal Switch, a Senis magnetic field transducer, an electromagnet and an
appropriate computer and software or an external analog programming signal.
The DC Supply provides current to the electromagnet via the Reversal Switch, and is safety
interlocked by means of a relay contact in the Reversal Switch. The Supply’s output is enabled
on a closed contact, providing protection should the interlock cable be disconnected. Two
conditions will cause the interlock relay to open, shutting down the DC Supply’s output: An
internal fault detected in the Reversal Switch or a failure in the temperature or water flow
interlocks on the electromagnet.
The 5971-160 Current Reversal Switch is comprised of several sections: A proprietary MOSFET
switch and associated control electronics, a National Instruments USB-6251 Control with USB
interface and an auxiliary power supply all integrated into a single 19” rack mounting chassis.
Refer to drawing no. 13907-0008-0, Rev. A for an internal block diagram.
The auxiliary power supply provides power for the cooling fans, interlocks, control circuitry
and interface. It also provides -12V and +12V (400mA each) on the rear panel for an
optional external Senis Magnetic Field Transducer for magnetic field measurement and
closed-loop field control.
The interlock circuit for the magnet requires a ‘closed contact’ connection. Provision for
both the magnet over temperature and water flow is provided, and a failure of either one is
indicated on the front panel of the Reversal Switch. When using the NI USB-6251 DAQ,
this information is available via the computer control software. In the event of a magnet
interlock fault, the output of the DC Supply is inhibited.
The NI USB-6251 DAQ interface provides computer control and monitoring of the system.
It uses a 16-bit analog output (±10V) to provide the programming signal to the DC Supply.
The output voltage and current are monitored by two 16-bit input channels. Complete
Reversal switch and magnet interlock status is also monitored via its digital input channels.
When using an optional Senis Magnetic Field Transducer, the field is read back on a third
16-bit analog channel. For more information, please refer to the NI USB-6251 Manual and
section 4.5 in this manual.