Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 74)

Operating Your PLC-5 Backup System
Chapter 5
5-10
With 1785-BCM module, 32 input bits are available in the PLC-5 processor
image table. (The 32 output bits in the output image table are unused and
reserved.) These input words are called Auxiliary Diagnostics/Status Words and
they provide further information about the 1785-BCM module and the
1785-BEM backup expansion module in both the primary and secondary
systems. Refer to Figure 5.6.
Figure 5.6
Auxiliary Diagnostics/Status Words
RESERVED EXTENDED STATUS
Channel 1A
Status Channel 1B
Status Channel 2A
Status
2
Channel 2B
Status
2
01 1 07 1 10 1 17 1
1st Word
2nd Word
W1
W2
W1 Bits:
Bits 00 to 07 = Reserved for Block Transfer Communication
Bit 10 = 1785-BCM series A module
Bit 11 = Fast Data Transfer mode
Bit 12 = Reserved
Bit 13 = Reserved
Bit 14 = Reserved
Bit 15 = Reserved
Bit 16 = Switchover Diagnostic
Bit 17 = 1785-BEM module
W2 Bits:
Bits 00 to 07 = 1785-BEM module communication channels status
Bits 10 to 17 = 1785-BCM module communication channels status
1 Note that these bits are in octal format because they correspond to the input image table.
2 Bits 00 to 07 of the second word can be used or not, depending on whether the 1785-BEM module is in
the backup system or not.
11058I
The first word address corresponds to the module slot, that is, the location of the
1785-BCM module in the I/O chassis. The least-significant byte of this word is
reserved to the 1785-BCM module usage and the most-significant byte shows
extended status of the module. Refer to Table 5.C.