Data Exchange with the SM 335
3-21
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Measuring cycle time (DR1, Byte 10)
The “measuring cycle time” parameter specifies the length of a measuring cycle.
Permissible values are those from 01
H
to 00
H
.
The default value is 01
H
.
The value 01
H
specifies a free cycle, i.e., a measuring cycle has a duration of
about 0.9 ms (if additional analog outputs are updated, 1 to 1.2 ms are required,
depending on the number of analog outputs).
02
H
corresponds to a measuring cycle of 1 ms, 03
H
to a measuring cycle of
1.5 ms, and so on.
00
H
corresponds to a measuring cycle of 16 ms.
Note
Measuring cycle time of 1 ms:
The output values are modified before the first measurement (channel CH3). The
measurements are then made. To ensure that all input and output channels are
serviced within 1 ms, there are no short-circuit or measuring range violation
diagnostics for a measuring cycle time of 1 ms. The Comparator function is not
executed in a 1 ms cycle.
The lack of time means that Comparator 1 cannot be executed!
Dynamic measuring cycle control (DR1, Byte 11)
The “dynamic measuring cycle control” parameter cannot be set with HW Config. It
is used for switching to special operating modes. This byte always has the va-
lue 00
H
in Free Cycle and Conditional Cycle modes.
= 0: Switch mode off
= 1: Switch mode on
“Measuring Only” mode
“Comparator” mode
76543210
Fig. 3-4 Meaning of the bits in the “dynamic measuring cycle control” byte
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