Rockwell Automation 1771-QB Linear Pos. - Manual (Page 69)

Interpreting ModuleĆtoĆPLC Data
(READS)
Chapter 6
6Ć8
Bit 6 – Position Valid
The position valid bit is on if the next two status block words (i.e., words 4 and
5 for axis 1 and words 8 and 9 for axis 2) contain a valid axis position.
Bit 7 – Diagnostic Valid
This bit is on if the next two status block words (i.e., words 4 and 5 for axis 1
and words 8 and 9 for axis 2) for this axis contain diagnostic information.
Bit 8 – Integral Limit Reached
The integral limit reached bit turns on if the integral term of the PID algorithm
reaches the maximum specified in the parameter block. (See Chapter 7.) It turns
off when the integral term returns to within the permitted limits. Reaching the
integral limit doesn’t result in a loop fault.
Bit 9 – Excess Following Error
If the following error equals or exceeds the maximum following error
programmed into the parameter block, the module turns this bit on and activates
OUTPUT 2 if configured as the loop fault output.
Bit 10 – PID Error
If the positioning error equals or exceeds the maximum PID error programmed
into the parameter block (if the PID bit is on), the module turns this bit on and
activates OUTPUT 2 if configured as the loop fault output.
Bit 11 – Immediate Stop
The stop bit turns on when the module recognizes a hardware stop input or
immediate stop command. The module also activates OUTPUT 2, if configured
as the loop fault output, when it performs an immediate stop.
Bit 12 – Discrete Input Fault
The discrete input fault bit turns on when the module detects a fault in the
discrete input circuitry. In this event, the module also activates OUTPUT 2 if
configured as the loop fault output. The following conditions will cause a
discrete input fault:
loss of discrete input power
discrete input circuitry fault