Function: Current Control - Siemens SIMATIC ET 200SP Manual

Modes and Functions

3.11 Function: Current control

3.11 Function: Current control
Current control (PWM mode only)
In PWM mode, the TM Pulse 2x24V module can use a proportional-integral-derivative (PID)
algorithm to control output current. The target value of the current (set point) is determined
by your program and the module controls the duty cycle of the PWM output to follow the set
point, with a response that is based on the assigned PID parameters.
The set point and the measured value of the load current are compared by the PID
controller. If the resulting difference (error) is outside a symmetrical dead band, a reaction is
calculated by adding the selected proportional, integral and/or derivative parts. The
manipulated value is limited by the defined high/low limits and finally the output pulse
duration time (duty cycle) is modified, depending on the PWM period duration.
Assign the reference current value to the current measured in the channel's DQn.A output
load when the output is continuously in the high (On) state.
Figure 3-14 Current control PID function
For more information about this PID control method, refer to the CONT_C instruction topic in
TIA Portal online help.
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Technology module TM Pulse 2x24V (6ES7138‑6DB00‑0BB1)
Manual, 09/2015, A5E35061186-AA