Timing Considerations; Timing Constraints When Using Advanced Functions; Timing Overhead For Functions Enabled - Siemens SIMATIC 505 Installation And Operation Manual

3.4

Timing Considerations

Timing Constraints
When Using
Advanced
Functions
3-18 Advanced Function Programming
Without any of the advanced features enabled, the SIMATIC 505–2556
module will update all 16 points in less than 6 msec. With all functions
enabled for all 16 points, the module will update all 16 channels in less than
56 msec. Each function has a specific overhead associated with it and your
application should consider the time delays to ensure that there is adequate
time allowed for the processing of data.
Table 3-7 shows a chart of the overhead required for all 16 channels when
each of the advanced functions is enabled. Operations such as scaling and
offset mode require the greatest amount of time due to the multiplication
and division in the microcomputer.
Table 3-7 Timing Overhead for Functions Enabled
Functions Enabled in Enhanced Mode
(32 WX and 32 WY, 16 X and 16 Y)
None
Low alarm
High alarm
Scaling
Offset mode
Filtering
Averaging
Averaging reset (16 channels)
Peak hold
Valley hold
16 WX MODE
No digital filtering
Filtering enabled
SIMATIC 505–2556 Installation and Operation Guide
Time for All 16
Channels
6.5 msec
7.73 msec
7.73 msec
27.1 msec
27.1 msec
8.97 msec
7.85 msec
41.8 msec
7.65 msec
7.65 msec
5.80 msec
8.20 msec