Digital Control Port
Series N6700 User’s Guide
145
External Trigger
Any of the Digital Control pins can be programmed to function either
as trigger inputs or trigger outputs. All three pins are referenced to
the Signal Common pin.
To input an external trigger signal, you can either apply a negative-or
a positive-going pulse to the designated trigger input pin. The trigger
latency is 5 microseconds. The minimum pulse width is 1
microsecond. The pin’s polarity setting determines which edge
generates a trigger-in event.
When configured as a trigger output, the designated trigger pin will
generate a 2 microsecond-wide trigger pulse in response to a trigger
event. Depending on the polarity setting, it can be either positive-
going or negative-going when referenced to common.
Fault Output
The Fault Output function enables a fault condition on any channel
to generate a fault signal on the Digital Control port. The following
conditions will generate a fault event: over-voltage, over-current,
over-temperature, inhibit signal, and power-fail (low AC-line).
When this function is selected, both pins 1 and 2 are dedicated to this
function. Pin 1 is the Fault output; pin 2 is common for pin 1. This
arrangement provides an optically-isolated output. Pin 2’s selected
function is ignored. Note that the Fault output signal remains latched
until the fault condition is cleared. You must also clear the protection
circuit.
Inhibit Input
The Inhibit Input function lets an external input signal control the
output state of all of the output channels in the mainframe. The
signal latency is 5 microseconds. The Inhibit function is only
available on pin 3. Pin 4 is common for pin 3. Pin 3 can be
programmed for the following Inhibit modes:
LATChing
Causes a logic-true transition on the Inhibit input to disable all outputs.
LIVE
Allows the enabled outputs to follow the state of the Inhibit input. When the
Inhibit input is true, the outputs are disabled. When the Inhibit input is false,
the outputs are re-enabled.
OFF
The Inhibit input is ignored.
Output channels can only be controlled by the inhibit signal if they
have previously been turned on by the OUTPut:STATe command or
by the front panel On/Off switch. If an output channel has been
turned off, it cannot be controlled by the Inhibit signal.
When an Inhibit signal turns off the outputs, the front panel INH
status annunciator comes on and the INH bit is set in the
Questionable Status Event register. To re-enable the outputs if the
inhibit signal was latched, you must clear the protection circuit.
