4
Introduction
The
3132
16-Channel AC Digital Output Card provides switching control of 16 channels of AC
line-voltage circuits.
The card’s output circuits incorporate optically isolated triac drivers, which provide isolation
between the field outputs and the RTP system ground, and isolation from channel to channel.
Zero-voltage crossing detectors control the power triac switches, which reduce load transient
currents. An output register allows the host to read back the states of the outputs.
The card also includes an onboard temperature sensor.
I/O Bus checking diagnostics are performed for all output data, status, and command transfers to
and from the output card. Each transfer is performed twice (all the data bits in the second
transfer are inverted). Both transfers are then compared to ensure that no errors exist in the data
path between the output card and the Chassis Processor. I/O Bus slot address and control signal
contention diagnostic tests also are performed.
Watchdog timers on the card can open all of the output channels in the event backplane
communication errors persist.
An LED, located near the top of the front panel, indicates the overall status of the card. If this
LED is on, the card is functioning normally; if the LED is off, the card has detected an error or is
offline.
