Siemens SIMATIC S5 CP 523 Manual page 43

CP 523
4 Notes on Operation
4.1 Restart Characteristics
The CP 523 executes a restart routine when the power supply is restored (POWER ON).
The restart procedure consists of the following:
• Clearing the Send and Receive mailboxes
• Checking the module ( 4.1.1)
• Memory submodule evaluation ( 4.1.2)
• Clock test ( 4.1.3)
If errors occur during the restart procedure, the CP 523 forwards an error flag to the CPU in byte 0
"Module status" (Print mode 6.6, Communications mode 7.4).
Note:
The message buffer is not deleted on restart in Print mode if the module was battery-backed and
the memory submodule has not been replaced.
4.1.1 Checking the Module
In this part of the restart procedure, the proper functioning of the hardware is checked. Errors are
assigned an appropriate number in byte 0 "Module status" and can be evaluated in the control
program or with the programmer.
Error/Fault
Number in Byte 0
1X
H
8X
H
X7
H
XF
H
X : can assume different values
EWA 4NEB 811 6044-02a
Table 4-1. Module Errors/Faults
Error
Clock defective
Hardware fault
No battery backup
CP in restart routine
Remedy
Replace module
Replace module
Insert new battery in the power supply
module
Scan the status byte for XF
the first job request
Notes on Operation
before issuing
H
4-1