Spectrum Controls SLC 500, User Manual

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3-6 Chapter 3: Configuring the 1746sc-CTR4/CTR8
User’s Manual Pub. 0300181-07 Rev. A
NOTE
The module’s Channel LEDs 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 will not override the external counter input.
Section 3.6 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.
Section 3.7
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.
WARNING
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 which may cause injury to personnel or damage to equipment.
Input Response
When a counter slot is disabled, the counter module continues to update its input
image table. However, the SLC processor does not read input from a module that
is disabled. Therefore, when the processor disables the counter module slot, the
module inputs appearing in the processor table is not read. When the processor
re-enables the module slot, the current state of the module inputs is read by the
processor during the subsequent scan.
Output response
The SLC processor may change the counter module output data (configuration)
as it appears in the processor output image. However, this data is not transferred
to the counter module. The outputs are held in their last state. When the slot is re-
enabled, the data in the processor image is transferred to the counter module.