Isochronous Mode - Siemens SIMATIC S7-1500 Manual

Product overview
2.2 Functions
● Incremental encoder (A, B phase-shifted, quadruple):
Output pulses are output by both outputs at the specified velocity, but phase-shifted by
90 degrees. This signal type involves a quadruple pulse output in which each edge
transition corresponds to one increment. Therefore, a complete period of signal A
contains four increments. In this way, it is possible, for example, to use two outputs, each
with 100 kHz signal frequency, to output a control signal that supplies 400,000
increments per second.
Whether count pulses are generated in the positive or negative direction of rotation
depends on the edge direction of one signal and the logic state of the other signal in each
case.
2.2.2

Isochronous mode

The technology module supports the system function "isochronous mode" in distributed
mode on PROFINET.
In isochronous mode, the cycle of the user program, the transmission of the input and output
data and the processing in the technology module are synchronized with each other.
Data processing
At time T
for retrieval in the current bus cycle. At time T
speed setpoint.
16
A precedes B (positive direction of rotation)
Number of pulses
the current position value is acquired and made available in the feedback interface
i
A follows B (negative direction of rotation)
Number of pulses
the pulse output is adjusted to the current
o
Technology Module TM PTO 4 (6ES7553-1AA00-0AB0)
Manual, 12/2016, A5E38896703-AA