Rockwell Automation 1771-PD PID MODULE (+DU) - Manual (Page 84)

Programming
Chapter 3
3Ć41
BCD Code Block Transfer Errors
70
80
81
82
Communication Fault. The number of block transfer words
exceeds the number expected by PID module.
Less than 12 words transferred in the standard loop constant
block.
Less than 19 words transferred in the expanded loop constants
block.
Loop 1 or loop 2 constants block can be transferred only in a
load/enter sequence.