The ET200S 1COUNT24V module has been innovated and is now available
with a new order no.. The module with the previous order no. is no
longer available. The new module now permits high-resolution
continuous-period measurements with a 1/16 microsec. resolution
(previously only 1 microsec. resolution). This enables the
1COUNT24V module to be used for indirect speed measurement with
high accuracy, as is required for control tasks in the textile
Application example for the function " high-resolution
Application: Thread winding
Thread is typically wound at a speed of 15 000 RPM.
To ensure that the winding process can be controlled with the
required accuracy, the speed must be measured with a variation of
not more than 3 RPM.
The speed is measured with a simple 24V encoder, which supplies 4
pulses per revolution, i.e.: Input frequency = 1 kHz at the 24V DI
at 15 000 RPM.
Solution based on ET200S 1COUNT24V (order no.:
The operating mode "continuous-period measurement" of the ET200S
1COUNT 24V module is used.
The time between rising and falling edge of the pulse of the 24V
encoder is measured and the speed of rotation is calculated. With
the new sampling frequency of 16 MHz the resolution will be 1/16
microsec., i.e. the speed can be measured with a variation of
approx. 1 revolution.
The closed-loop control algorithm will be executed by the S7-CPU
with a cycle time of approx. 20ms.
For the configuration of the new module with the function "
high-resolution continuous-period measurement", STEP7 V5.1, SP2 is
a precondition. However, the new ET200S 1COUNT24V module can also
be configured with previous STEP7 versions under the previous order
no. of the module, but without the new functions in this case.
Your SIMATIC contact at your local Siemens office will answer
any further questions you may have.