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Description
Model 427 interfaces four incremental encoders
to the ISA bus. Three flat cables connect the Model 427 to external breakout boards.
Encoders
The four 24-bit up/down counter channels
are optimized for incremental encoders. Each channel accepts two phased TTL or RS-422
signals, plus an index signal. Unlike conventional counters, the 427 counters do not
accumulate errors when the encoder dithers or changes direction.
Load-on-event - Each channel may be loaded with a preset
count. The channels may also be programmed to load the preset count upon the occurrence of
an index pulse, a terminal count, or a match count. |
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Digital I/O
The model 427s sixteen digital lines have
standard pin-outs for solid-state relay boards. Each line is software programmable as an
input or output. Inputs may be programmed for edge detection and interrupts. The status of
output lines may be monitored by software. Whenever a system reset occurs all output
channels are turned off.Interrupts - each counter
channel may be programmed to generate an interrupt upon
detecting an index pulse, a preset or terminal count.
Digital I/O lines programmed as inputs may generate interrupts when their state
changes. |
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