Automatic control function programming manual ladder language

2.1.3.2 1060 Series II- UCSII Systems
Normal Operation
Structure of an Application
The user programme is clocked by the RTC with a 20 ms cycle. Its duration is however limited by parameter P99 (see
Parameter Manual). Parameter P99 is a multiple of 2 ms between 4 and 18 ms. Processing of %TS tasks should
normally be completed before occurrence of IT P99.
RTC occurrence
MONITOR
< 5 ms
Consecutive Overruns
P99 ms
20 ms
User programme
(%TSn + %TFn)
IT P99
RTC occurrence
MONITOR
< 5 ms
A slight overrun of IT P99 is tolerated in processing of tasks %TS. Each overrun, the system increments the RTC
overrun counter %R97C.W.
If the RTC interrupt occurs before the %TS tasks are completed, the monitor is immediately restarted.
The system accepts a maximum of three consecutive overruns.
The fourth overrun increments the RTC overrun counter %R97C.W and causes the CPU to go into HALT_ON_ERROR
state.
MONI
TOR
MONI
TOR
RTC occurrence IT P99 IT P99 IT P99 IT P99
%R97C.W was incremented %R97C.W was incremented %R97C.W was incremented
HALT_ON_ERROR state
MONI
TOR
User
programme
User
programme
RTC
User
programme
RTC RTC
1 2 3 4
MONI
TOR
User
programme
RTC RTC RTC
MONI
TOR
User
programme
1 2 3 4
MONI
TOR
User
programme
RTC occurrence IT P99 IT P99 IT P99 IT P99
MONI
TOR
User
programme
MONI
TOR
%R97C.W was incremented %R97C.W was incremented %R97C.W was incremented
User
programme
HALT_ON_ERROR state
REMARK Although a user programme may not create an overflow when operating off load (e.g.
without machining parts), overflows may occur on load due to CNC hardware tasks
(feedback processing, etc.) or ITs (serial lines, etc.) added in the interval between two
RTCs.
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