Rockwell Automation 1734-SSI POINT I/O Synchronous Serial Interface Absolute Encoder Module User Manual - Manual (Page 33)

Publication 1734-UM007D-EN-P - December 2005
Set and Operate Your Module 4-5
Comparators 1 and 2
You can store two separate four-byte values and be notified when the
SSI sensor attains or exceeds the stored value. Comparators 1 and 2
are mutually exclusive: only one comparator can be active at any
given time.
You can set a comparator to trigger on an increasing sensor count,
decreasing count, or regardless of sensor direction, by choosing Both
for the comparator control value. There are two modes of comparator
operation: manual and automatic. The green COMP LED on the front
of the module illuminates when a comparator value is reached. The
LED goes OFF when comparator reset occurs.
See the table for a listing of values for DeviceNet name, RSLogix 5000
tag, and RSLogix 5000 field name for Manual and Automatic mode.
Manual Mode
Select Manual mode by entering a comparator value and a
corresponding control value (increasing, decreasing, or both). If you
are using Comparator 2, for example, you notice Bit 7 of Status Byte 0
(C2ST) is 1 when Comparator 2 is active. To reset the comparator,
toggle (set to 1 for at least 0.5 ms, then back to 0) the Comparator 2
acknowledge bit, Bit 2 of the Master Ack Byte (CC2).
You can also reset Comparator 2 by turning it OFF through the
configuration. Comparator 1 uses Bits 6 (C1ST) and Bit 4 (C1R) of
Status Byte 0 for operation. Bit1 (CC1) of the Master Ack Byte is used
for reset. Like Comparator 2, you can also reset Comparator 1 by
turning it OFF through the configuration.
Manual and Automatic Mode
DeviceNet Name RSLogix 5000 Tag RSLogix 5000 Field Name
C1ST Input Compare0Status
C2ST Input Compare1Status
CC1 Output Compare0Ack
CC2 Output Compare1Ack
C1R Input Compare0Reached
C2R Input Compare1Reach
SCMP1 Output Compare0Select
SCMP2 Output Compare1Select