Siemens SIMATIC ET 200S Operating Instructions Manual page 331

Additional Applications
Limit-value monitoring of the temperature: To monitor the limits of the temperature of the
medium, use a temperature sensor evaluated by an analog module. You can monitor the
temperature with your control program.
Temperature control: To control the temperature of the medium, use a temperature sensor
evaluated by an analog module. You can use one of the software controllers of SIMATIC S7
to do this. Pass on the manipulated variable calculated by the software closed-loop controller
directly to the 2PULSE using your control program. If you require separate actuators for
heating and cooling, use the second channel of the 2PULSE. If you detect a negative
manipulated variable in your control program, pass on the value to the second channel of the
2PULSE.
Heating up a liquid with a heat exchanger: Basic actuators that only have two end settings
(OPEN/CLOSED) create an almost continuous manipulated variable through the control of
the 24 V control signal. This will enable you to control, for example, the flow through a heat
exchanger using a solenoid valve.
Figure 5-26
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Using a Solenoid Valve to Control the Flow
2PULSE
5.7 Application Examples
331