Data Exchange with the SM 335
3-28
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Dynamic measuring cycle control
Byte 11, “dynamic measuring cycle control”, has two tasks:
•
To switch on ‘Measuring Only’ mode
•
To disable/enable analog inputs
Switching on the operating mode (DR1, Byte 11)
To switch on “Measuring Only” mode, you must transfer all the SM 335 parameters
and set bit 6 + 7 in byte 11:
7
6
5
4
3
2
1
0
“Measuring Only” mode
= 0: Switch mode off
= 1: Switch mode on
“Comparator” mode
Fig. 3-8
Dynamic measuring cycle control for “Measuring Only” mode
Dynamic disabling of analog inputs (DR1, Byte 11)
You disable the associated analog input with bits 0 to 3. The default for bits 0 to 3
is ’0’. Setting a bit to ‘1’ disables the associated analog input. If you disable three
analog inputs, it is possible to attain a measuring cycle time of < 0.5 ms.
7
6
5
4
3
2
1
0
Analog input CH0
Analog input CH1
Analog input CH2
Analog input CH3
= 1: Analog input disabled
= 0: Analog input read in
“Measuring Only” mode
= 0: Switch mode off
= 1: Switch mode on
“Comparator” mode
Fig. 3-9
Meaning of the bits in the “dynamic measuring cycle control” byte
Bit 4 in the “dynamic measuring control” byte must be ’0’.
