Characteristics and Technical Specifications of the SM 335
1-13
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
1.6
SM 335 operating modes
Operating modes
The SM 335 can operate in the following modes:
•
Free cycle (corresponds to HW Config setting for SM 335: 0.5 ms cycle time)
•
Conditional cycle (corresponds to HW Config setting for SM 335:
1 to 16 ms cycle time)
Special operating modes
In addition, the SM 335 can be switched to the following modes for a brief period of
time:
•
“Comparator” special mode
•
“Measuring Only” special mode
The special operating modes are described in Chapter 5, where there is also a de-
scription of how to switch to the special operating modes.
1.6.1
Free Cycle mode
Cycle
In conjunction with the SM 335, the word “cycle” is used to mean the measuring of
the analog value at all analog inputs in succession. Once the measuring cycle is
complete and all inputs have been read, the cycle starts again from the beginning.
This cycle has nothing to do with cyclic program scanning on a SIMATIC S7 CPU.
Free Cycle
When the SM 335 operates in Free Cycle mode, all SM 335 analog inputs and out-
puts are processed successively and without interruption. After all inputs and out-
puts have been processed, conversion once again begins with the first analog in-
put.
Free Cycle mode is activated when a cycle time of 0.5 ms is set for the SM 335 in
HW Config.
