Rockwell Automation 1771-QB Linear Pos. - Manual (Page 73)

Interpreting ModuleĆtoĆPLC Data
(READS)
Chapter 6
6Ć12
Figure 6.6
Position Format
50055
Position value,
BCD or binary format
799.900 inches or 7999.00 mm max
Most significant 3 digits Sign:
0 = +
1 = -
Sign:
0 = +
1 = -
Least significant 3 digits*
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* As long as the parameter control word (see Chapter 7) is configured for binary (bit
3=0) and single word (bit 7=1) formats, values between -32.768 inches and 32.767
inches (-327.68 mm and 327.67 mm) may be displayed entirely in the second word.
The first word will be zero.
Following Error Information (words 4, 5; 8, 9; 16, 17; and 18, 19)
Following error is determined by subtracting the actual position of the axis
measured at the transducer from the desired position calculated by the module.
The desired position is calculated every two milliseconds based on the
acceleration, deceleration and velocity of the move. The error information is in
either BCD or binary format. You choose the format you want through the
parameter block. Binary format is compatible with integer data (16-bit 2’s
complement) used by PLC-5 family programmable controllers. See Appendix H
for an explanation of numbering formats.
The maximum following error displayed in the status block is
±
180.000 inches
or
±
4572.00 millimeters. If the status words 4, 5 and 8, 9 are specified in the
command block to display errors, when the axis exceeds the maximum, the
maximum is displayed and the error valid bit in the second status word turns
off.