Specifications

44 System Instrument Configuration Chapter 2
Isolated V/I Source The V/I programmable current and voltage source are similarly multiplexed
to the interconnection column (ABus). The V/I HiV and LoV amplifiers
allow the user to source a voltage and measure the current or source a current
and measure the voltage. The V/I amplifier is fully isolated. The output is
fused, Agilent p/n 2110-0516, at 1 amp. It may be referenced internally to
UUT Common through a relay or used differentially. Isolation is possible
because the parallel data from the VXI backplane is converted to a serial bit
stream in a programmable logic array, passed though an optical isolator, and
then converted back to parallel data to control the V/I amplifier DACs.
The V/I uses two separate amplifiers: a low voltage amplifier (LoV) ±16 V
at 200 milliamp, and a high voltage amplifier (HiV) ±100 volt at 20
milliamp. The high voltage amplifier is powered from a dc-to-dc converter
that has a safety interlock to shut it down if the UUT fixture is removed.
The V/I amplifiers have three other functions. The ARB can use the V/I
source as an amplifier and current sensor. The ARB output can be amplified
through a transformer to high voltages. The programmable attenuator (Attn)
can adjust the input levels for digitizing. It can be used to linearly scale HiV
UUT signals for digital testing. This allows very high flyback signals to be
measured without damaging the components in the V/I amplifier. The
programmable comparator and open collector digital trigger allow
triggering between system instruments referenced to ground and the floating
UUT.
Trigger Multiplexer The trigger multiplexer consists of two independent bi-directional multiple
sources and multiple destination demultiplexer-multiplexer channels for
routing trigger signals to and from trigger resources. Trigger resources
include eight bidirectional TTL Trig In/Out from the VXI backplane and
eight bidirectional external trigger in lines. The triggers can also be
controlled by the Timer/Counter.
Status LEDs
Table 2-2. Agilent E6171 Measurement Control Module LEDs
Color Name Meaning when on
Green Access The VXIbus is reading from or writing to the module. The only time it will stay on is if you are repeatedly
addressing the module.
Red Fail If the LED remains on after the VXI mainframe is powered on, it means that the module didn't power up
correctly and the problem is probably the module. If the LED comes on during operation, it may mean +5 Vcc
is not stable (glitching low or high) which will cause the control circuitry to become unstable. The Vcc monitor
circuit will reset the circuitry, disable the board and turn on the Fail LED. If the Fail LED is on, you cannot
access the module and you will need to troubleshoot the cause of the Fail LED being on.
Green IRQ Means that there is an interrupt pending that has not been serviced. If you are not using interrupts and the
IRQ LED is on, that is an indication of a problem.
Red Interlock Safety Interlock is open. That means that you cannot close any relays or turn on the high voltage on the V/I
amplifier until the event has been cleared. One cause for this may be that the UUT fixture is removed,
opening the high-voltage safety interlock.
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