Data Exchange with the SM 335
3-23
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
3.3.3
SM 335 parameter for “Comparator” mode
In “Comparator” special mode, the SM 335 compares a specified analog value with
the analog value measured on one of the analog inputs. The SM 335 behaves like
a comparator in this operating mode. For detailed information about “Comparator”
mode, see Section 5.2.
Switching
Chapter 5 describes how to switch to the “Comparator” mode.
Restrictions
The parameters for “Comparator“ mode can be transferred with system function 55
WR_PARA only.
Data record DR1 must always be transferred completely (bytes 0 to 13).
Data Record 1
The parameters that can be switched dynamically are stored in data record 1 of
the SM 335 (see Table 3-13).
Table 3-13
SM 335 data record 1 for “Comparator” special mode
Byte
Content
0
High-order byte of analog output value 1
1
Low-order byte of analog output value 1
2
High-order byte of analog output value 2
3
Low-order byte of analog output value 2
4
High-order byte of analog output value 3
5
Low-order byte of analog output value 3
6
High-order byte of comparison value for “Comparator 1”
7
Low-order byte of comparison value for “Comparator 1”
8
High-order byte of comparison value for “Comparator 2”
9
Low-order byte of comparison value for “Comparator 2”
10
Comparator time
11
Dynamic measuring cycle control
12
Comparator control byte
13
Reserved
