Introduction.

Workshop PG5
Program structures
All the XOB’s of
the PCD family:
XOB Description Priority Cold Start
0 Power problem in the main rack (PCD6) or
4 *
WatchDog (PCD1/2)
1 Power problem in the extension rack (PCD 6 ) 2
2 Battery low 2
4 Parity error on the I/O bus (PCD6) 1
5 No response on a module I/O (PCD4/6) 1
6 External error 1
7 Over load of the system due to multiple events. 1
8 Instruction not valid 4 *
9 To many active tasks (Graftec) 1
10 To many PB/FB levels 1
11 Watch dog COB 3
12 To many index registers used 1
13 Error Flag 1
14 Interruption cyclic 3
15 Interruption cyclic 3
16 Cold start 4
17 S-Bus telegram 3
18 S-Bus telegram 3
19 S-Bus telegram 3
20 Interrupt input INB1 3
25 Interrupt input INB2 3
30 No connection with RIO 1
Use of XOB’s:
- Helps to find errors in your program configuration
- Errors in the addresses of the modules
- More then seven program levels
- More then 32 active transitions in a Graphtec structure
- Never ending loop
- Error in a mathematical operation
- Errors in the communication
- Maintenance of your PLC:
- Surveillance of the batteries (needs to be changed every 3 to 4 years)
- Surveillance of special events or very fast reactions on external signals:
- Interrupt inputs
- Interruption of the program every once and awhile
- Interruption of the program when a telegram arrives
- Cold start. Initial values
© SAIA-Burgess Controls AG Page 5-8