Special SM 335 Operating Modes
5-5
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Comparator 1
Figure 5-3 shows how Comparator 1 works:
Execution time of
the system
function
System function
Exit operating mode
Comparator 1
Comparison value
Analog value at
analog input
Time
Time
Active
Not active
Fig. 5-3
How Comparator 1 works
After you have called system function 55, switched the SM 335 to “Comparator”
mode and switched on only comparator 1, the SM 335 compares the analog value
at the specified analog input with the comparison value.
The analog inputs continue to be updated and can be read using peripheral input
words. During this special operating mode, analog outputs are frozen.
When the specified analog value is reached, the SM 335 exits “Comparator” mode.
After exiting “Comparator” mode, the SM 335 outputs the analog values specified
in system function 55. It continues to output these analog values until you forward
a new analog value. The new analog value must differ in at least one bit from the
one output in “Comparator” mode.
Note
Comparator 1 does not run with cycle time 1 ms.
