Data Exchange with the SM 335
3-24
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Analog output value
With Comparator 1 or 2, the SM 335 outputs the specified analog values on up to 3
analog outputs (see Section 5.2).
Comparator time (DR1, Byte 10)
During the time Comparator 2 is active, the SM 335 cannot generate a hardware
interrupt for the end-of-cycle. It can therefore happen that the SM 335 does not
generate an end-of-cycle interrupt for an extended period.
You can use the comparator time to specify how long the comparator can remain
active.
If the comparator is active and the comparator time has expired, the SM 335
switches back autonomously to “Conditional Cycle” or “Free Cycle” mode.
The comparator time is specified in milliseconds (1
=
1 ms, 2
=
2 ms,
to 0
=
256 ms).
Dynamic measuring cycle control (DR1, byte 11)
The dynamic measuring cycle control byte has the following assignments in
“Comparator Mode 1”:
7
6
5
4
3
2
1
0
= 0: Switch mode off
= 1: Switch mode on
“Measuring Only” mode
“Comparator” mode
Comparator Mode
Analog input
Comparator 1
00 – Analog input CH0
01 – Analog input CH1
10 – Analog input CH2
11 – Analog input CH3
Analog input
Comparator 2
00 – Analog input CH0
01 – Analog input CH1
10 – Analog input CH2
11 – Analog input CH3
= 1:
Fig. 3-6
Meaning of the bits in the “dynamic measuring cycle control” byte
Bit 4 in the “dynamic measuring control” byte must be ’1’.
