V
OLTECH
AC
I
NTERFACE
U
SER
M
ANUAL
98-072
ISS
7
PAGE
41
'To AT Peripheral Port' (Fixed Cable)
This part of the fixture will have a factory-fitted cable. It is not intended to be replaced by the end-user. This
cable has a 15-way D connector on the end that must be plugged into the AT3600/AT5600 peripheral port. All
signals to and from the AT3600/AT5600, including the power supply for the AC Interface Fixture’s internal
circuitry, are sent down this cable.
'CT or Shunt'
These connections are used for fitting the primary of a CT or shunt resistor in series with the power path.
Without a CT or shunt fitted here, no low connection will be made to the output of the fixture. These
connections will carry the same voltages and currents as the external source input.
'Shunt Sense'
These connections are wired directly in parallel with the ‘CT or Shunt’ connections to provide a Kelvin (or 4-
wire) connection to a shunt. These connections are used to carry the sense voltage from the shunt resistor
fitted to nodes 17 and 19 of the AT switching matrix.
'CT Input'
The AT3600/AT5600 can measure the current that is applied to these terminals. The secondary of any current
transformer that has its primary connected to the 'CT OR SHUNT' terminal should be connected here. The
maximum value is 1A RMS, 3.5Apk. The AT3600/AT5600 measures this current and multiplies the result by
the CT ratio (i.e., 20 for the Voltech CT10-20) to obtain the final current value.
