Special SM 335 Operating Modes
5-9
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
Application
Figure 5-6 shows an application for the comparator function:
Decelerate
Comparator 2
Comparator 1
Position
Fig. 5-6
Application for “Comparator” Mode
A mold is closed. The closing motion must be extremely fast. The position of the
tool can be acquired, for example, using a linear potentiometer.
The linear potentiometer’s analog signal is measured by the SM 335.
When the mold closes, the SM 335 switches to “Comparator” mode, with
Comparators 1 and 2 switched in series.
While the mold is being closed, Comparator 1 compares the measured analog va-
lue with the comparison value for Comparator 1. The analog value is reached when
the form has assumed a certain position. The SM 335 now activates Compara-
tor 2, and measures only the values at this analog input. Shortly before the mold is
closed, the measured analog value reaches the comparison value for Compara-
tor 2. A hardware interrupt is generated. You can initiate deceleration in the inter-
rupt OB. If the whole process is to be performed even faster, specify an analog
value that the SM 335 forwards to one of its analog outputs. Use this analog output
for direct control of the drive that moves the mold. In this way, you will achieve fast
closing and fast, repeatable deceleration.
