Siemens SIMATIC ET 200S Operating Instructions Manual page 342

2PULSE
5.7 Application Examples
Requirements
● A valve suitable for controlling (proportional valve)
● Suitable electric data of the valve (24 V, max. 2 A or 4 A with parallel connection of both
● When designing the control loop, take the additional data of the valve into consideration,
Time period and control cycle
● Select a time period less than or equal to the cycle time of the controller. For optimal
● Do not change the time period during operation.
Parameters
The following parameters are required for Channel 0 of the 2PULSE for the current
regulation of a valve with the "Pulse width modulation" operating mode.
Table 5- 5 Parameter list for current regulation of a valve
Parameter
Group diagnostics
Diagnostics DO 0
Response to CPU/master STOP
Operating mode
Output format
Time base
Function DI 0
On-delay
Minimum pulse duration
Time period
When setting this parameter, take the recommendations of the valve manufacturer into consideration.
1)
The parameters for Channel 1 are not relevant in this application example.
342
channels of the 2PULSE)
in particular the time constant of the contained inductance and the manufacturer's
recommendation regarding the time period of the PWM signal.
control quality, determine the cycle time of the controller on the basis of the time constant
of the inductance.
Set value
Enable
On
Turn off DO 0
Pulse width modulation
S7 analog output
0.1 ms
Input
0
0
50
Meaning
The following errors trigger a diagnostic message:
Short circuit digital output

Short circuit of the encoder supply

The 2PULSE detects the short circuit error on the digital
output DO 0.
This means that the corresponding output of the
controller can be used without further conversion.
The digital input is not required for this application.
The on-delay is not required for this application.
A minimum pulse duration has a negative affect on
control.
1)
In this example, 5 ms are set for the time period of the
PWM signal.
1)
Operating Instructions, 06/2010, A5E00124867-07
Technological Functions