Distributed positioning and control of stepper motors, actuators and valves
25 March 2010
Siemens Industry Automation & Drive Technologies has improved the performance of the two technology modules 2 PULSE and 1 STEP for the Simatic ET 200S distributed I/O system, and has also added new functions.
With the dual-channel technology module 2 PULSE that controls actuators and valves it is now possible to measure and precisely regulate the current that is output. A new traversing task for approaching a specified position has been integrated in the single-channel stepper motor module 1 STEP for positioning tasks in combination with stepper motors.
The dual-channel technology module 2 PULSE for controlling actuators and valves now also measures the current that is output in the PWM (pulse width modulation) and pulse train modes and sends the value back to the CPU. This enables simple proportional valves to also be directly connected and precisely controlled. This means a further improvement in the precision of control in isochronous mode. To improve performance the two channels of the module can be switched in parallel, thus providing a current of up to 4 amps. Further modes are frequency output, output of a pulse with a predefined length, and ON/OFF delay.
There is also a new "traversing task" for approaching a specified position on the single-channel stepper motor module 1 STEP. In speed mode the frequency specified by the controller is transmitted to the output taking the acceleration/deceleration ramp into account. This mode is suitable for use with a higher-level positioning control, also in isochronous mode if required. The 1 STEP module has two digital inputs that can be configured as a reference point switch, a limit switch, or as an external start enable.
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