Computer Drive Installation Instructions

09.95 8 PLC Machine Data (PLC MD)
8.2 PLC MD for the operating system (system data)
8.2 PLC MD for the operating system (system data)
Time base for calling OB 5
2
Default value Lower input limit Upper input limit Units
1 +1 3 2.5 ms
DB 60
DW 2
Time base for calling OB 6
3
Default value Lower input limit Upper input limit Units
1 +1 9 10 ms
DB 60
DW 3
Time base for calling OB 7
4
Default value Lower input limit Upper input limit Units
1 +1 255 100 ms
DB 60
DW 4
You can use the organization blocks OB 5, OB 6 and OB 7 for time-controlled program
execution.
You can vary the time base by specifying a factor. This factor is specific to the block:
Blocks
Normal time
base
Factor
OB 5 2.5 ms 1 to 3
OB 6 10 ms 1 to 9
OB 7 100 ms 1 to 255
You must not specify zero as a factor.
If you want to use OB 5, set PLC MD 6051.0 to 0 to enable OB 5 to be invoked. See also
PLC MD 6050 (enable block for processing) and PLC MD6048 (processing delay).
Last STEP 5 timer
5
Default value Lower input limit Upper input limit Units
64 -1 +255 –
DB 60
DW 5
The processing of timers causes a certain amount of work for the PLC operating system.
Should a user program require e.g. only timers 1 to 20, entry of the number 20 tells the
operating system that it should process only these timers. This saves processor time, and can
even reduce the PLC cycle time.
An entry of "-1" disables all timers.
The extension to 255 is only possible with option N05; otherwise 127 timers are available.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 8–3
SINUMERIK 840C (IA)