Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 217)

Troubleshooting
Chapter 10
10Ć5
Turn on bit 11 to display the diagnostic status as shown in Figure 10.4.
Also, this diagnostic status displays automatically when the 1771-M3
controller detects an error in the parameter block immediately after
power-up or an invalid ID in a command block. The diagnostic status
displays automatically in that case because the error prevents you from
selecting it thru the command block.
Figure 10.4
Position/FollowingĆError/Diagnostic Words Ć with Diagnostic Selected
17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
Word pointer - This BCD
number tells you which
word is in error within
the block.
Error code - This BCD
number references the
error listed in Table 10.A.
First Diagnostic Word
Second Diagnostic Word
17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
Block pointer - This BCD number is the
address of the block that is in error.
The second diagnostic word is the block pointer. The block pointer is a
BCD number that indicates the starting address of the block in error. The
1771-M3 controller gets these block pointers from the block pointers you
enter into the parameter block or the moveset block.
The high byte (bits 10 thru 17) of the first diagnostic word is the word
pointer. The word pointer is a BCD number (1 thru 64) that indicates
which word is in error within the block.