Siemens SIMATIC SM 335 - Page 92

Special SM 335 Operating Modes
5-6
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Comparator 2
Figure 5-4 shows how Comparator 2 works:
Execution time of
the system
function
System
function
Comparison
value reached
System
function
Comparator
time expired
Comparison value
Time
Comparator 2
Analog value at
analog input
Active
Not active
Time
Case B
Case A
Fig. 5-4 How Comparator 2 works
Case A: Comparison value reached
As soon as the measured analog value has reached the comparison value:
• The SM 335 generates a hardware interrupt.
• It outputs the specified analog values to the specified analog outputs.
• It writes the number of suppressed end-of-cycle interrupts to the input value
area (module address byte + 8) and
• It 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 (see also the Hint under “Case A and B”).