Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 75)

Operating Your PLC-5 Backup System
Chapter 5
5-11
Table 5.C
Extended Status Bits (W1)
Bit 1 Description
10 1785-BCM series A module; when on, this bit indicates that the other 1785-BCM module is
series A.
11 Fast Data Transfer mode; when on, this bit indicates that the data valid bit is set to 1 (one)
as soon as the secondary module receives a data block. When off, this bit indicates that the
data valid bit is 1 (one) only when the secondary module receives the complete data
segment.
12 Reserved – always 0
13 Reserved – always 0
14 Reserved – always 0
15 Reserved – always 0
16 Switchover Diagnostic; this bit is always off, but if during a switchover condition this bit is
on, it means that the module must be replaced.
17 1785-BEM module; this bit is on when there is a 1785-BEM backup expansion module in
the system.
1 Bits 0 through 7 (least significant byte of W1) are unused and reserved. For W1, bit 0 is the
least-significant bit and bit 17 is the most-significant bit.
The second auxiliary status word address corresponds to the right-most slot of
the first I/O module group in the I/O chassis. This word shows the channel
configurations of the 1785-BCM and 1785-BEM (if any) modules and also
indicates an error condition in any of these channels.
The most-significant byte of this word corresponds to Channels 1A and 1B of
the 1785-BCM module. The least-significant byte corresponds to Channels 2A
and 2B of the 1785-BEM module. Refer to Figure 5.7.
Figure 5.7
Second Auxiliary Diagnostics/Status Word
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00 07 10 03 04 13 14 17
W2
Channel 1A Channel 1B Channel 2A Channel 2B
Error Bit 11059I
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= error bit per channel