Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 116)

Diagnosing Faults
Chapter 8
8-6
Diagnosing Faults with Bits of the Auxiliary Diagnostic/Status Words
Bits of the two Auxiliary Diagnostics/Status Words provide further
information about the 1785-BCM backup module and 1785-BEM backup
expansion module (if any).
Important: The auxiliary diagnostic/status word bits in Figure 8.3 and
Figure 8.4 are in an octal representation (bits numbered 0–7 and 10–17).
In the first word W1, the least significant byte (bits 0–7) is reserved for
internal usage of the 1785-BCM module. The most significant byte (bits
10–17) provides extended status about the module. Refer to Figure 8.3.
Figure 8.3
Extended Module Status W1 (Auxiliary Diagnostic/Status Word)
10
11
12
13
14
15
16
17
BCM Module
Extended
Status Bits
1
1
Note that the first byte (bits 0–7) of W1 is reserved for internal usage of the 1785-BCM module.
Status
If bit
condition is:
2
2
Bit conditions: 1 = ON, 0 = OFF
then the description is:
1785-BCM
series A 0 The other 1785-BCM module is a series B.
1 The other 1785-BCM module is a series A.
Fast
Data-Transfer
Mode
0 Fast data-transfer mode is disabled.
1 Fast data-transfer mode is enabled.
Reserved
Switchover
Diagnostic 0 Normal operation.
1 Module failure occurred during switchover. Replace the module.
1785-BEM
Module 0 1785-BEM module is not part of the backup system.
1 1785-BEM module is part of the backup system.
Reserved
Reserved
Reserved
Bits of the second Auxiliary Diagnostics/Status Word W2 provide the
configuration of the 1785-BCM module and 1785-BEM module (if any)
channels, as well as indicate an error condition in any of these channels.
Refer to Figure 8.4.