Diagnosing faults chapter 8 – Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual User Manual

Page 115

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Diagnosing Faults

Chapter 8

8-5

Figure 8.2
System Status Word Error Indications

Remote BCM
module bits

Local BCM
module bits

8

9

10

11

12

13

14

15

0

1

2

3

4

5

6

7

If bit condition is:

1

Remote Local
BCM bit BCM bit

Error

then the error description is:

HSSL

I/O
chassis
backplane

0 0

Normal operation.

0 1

Communication fault between local processor and BCM

1 0

Communication fault between remote processor and BCM

1 1

Communication fault in both systems.

Buffer full

0 0

Normal operation

0 1

For local, see Note 2

1 0

For remote, see Note 3

1 1

Both Notes 2 and 3 apply

0 0

Normal operation

0 1

Communication fault with local BCM module

1 0

Communication fault with remote BCM module

1 1

Communication fault between local and remote modules

1

Bit

conditions: 1 = ON, 0 = OFF

2

Local BCM, if primary, is receiving 2nd segment after storing 1st, but did not send first segment to secondary BCM; if secondary, received 2nd segment

without processing 1st.

3

Remote BCM, If primary, is receiving 2nd segment after storing 1st, but did not send first segment to secondary BCM; if secondary, received 2nd

segment without processing 1st.

4

This is dependent on the Fast Data Transfer mode either being enabled or not enabled.

5

This is an invalid condition for the primary 1785-BCM module.

Program-
ming Error

0 0

Normal operation

0 1

Programming error in local processor

1 0

Programming error in remote processor

1 1

Programming error in both PLC-5 processors

Remote I/O
Communi-
cation

0 0

Normal operation

0 1

Remote I/O communication failure between local processor and BCM

1 0

Remote I/O communication failure between remote processor and BCM

1 1

Remote I/O communication failure between both processors and BCMs

Processor
Fault

0 0

Normal operation

0 1

Invalid condition

1 0

Remote processor failure or is in PROGRAM mode

1 1

Invalid condition

Primary/
Secondary
System

0 0

Invalid during operation; valid for power-up and switchover only

0 1

Local processor is in primary mode; PRI LED on local BCM is lit

1 0

Remote processor is in primary mode; PRI LED on remote BCM is lit

1 1

Invalid condition

Data
Valid

0 0

Secondary BCM is not ready to send blocks of data to processor
(no complete segments available in buffer)

4

0 1

5

Local BCM is in secondary mode and has a block or complete
segment available to send processor

4

1

5

0

Remote BCM is in secondary mode and has a block or complete
segment available to send processor

4

1 1

Invalid condition

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