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24
SLC 500
™
50 KHz Counter / Flowmeter Input Module
Gate Modes
There are two methods to gate (start/stop) your counter, hardware and
software. The counter’s gate/preset mode determines what, if any, gating
is applied to the counter and what, if any, conditions will preset the counter
to the preset value.
External Hardware Gate Lines:
There are four external inputs, one for each pair of input channels, that
may be used to start and stop the counter. Each external gate is pulled
low internal to the module. A low input allows each pair of counter
channels to operate. The count enable line is compatible with 5, 12, and
24 VDC inputs. If pulled high with one of these inputs the pair of
counter channels are disabled.
Note: The module’s Channel LED’s only indicate the state of the counters
start/stop bit. They do not indicate that state of the external hardware
gate.
Counter Start / Stop Bit
This bit allows the counter to continue to count up or down from its
present value. Starting, or enabling this bit wil not override the external
counter input.
Channel Turn-On,
Turn-Off, and
Reconfiguration Times
The time required for the module to recognize a new configuration for a
channel is one module update time.
Turn-off time requires up to one module update time.
Reconfiguration time is the same as turn-on time.
Response to Slot
Disabling
By writing to the status file in the modular SLC processor, you can
disable any chassis slot. Refer to your SLC programming manual for the
slot disable/enable procedure.
CAUTION
POSSIBLE EQUIPMENT OPERATION
Always understand the implications of disabling a module
before using the slot disable feature.
Failure to observe this precaution can cause unintended
equipment operation.
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