Siemens SIMATIC S7-1200

Technology instructions
10.3 Motion control
S7-1200 Programmable controller
662 System Manual, V4.2, 09/2016, A5E02486680-AK
Note
The CPU calculates motion tasks in "slices" or segments of 10
ms. As one slice is being
executed, the next slice is waiting in the queue to be executed. If y
ou interrupt the motion
task on an axis (by executing another new motion task for that axis), the new motion task
cannot be executed for a maximum of 20
ms (the remainder of the current slice plus the
queued slice).
10.3.3
Open loop motion control
10.3.3.1
Configuring the axis
You connect the open loop axis on the PLC and the drive through a PTO (Pulse Train
Output). For motion applications using PTO, the CPU requires onboard or signal board (SB)
digital I/O. This limits the number of axes that are available on the smaller PLCs.
STEP 7 provides the configuration tools, the commissioning tools, and the diagnostic tools
for the "Axis" technology object.
①
Drive
④
Commissioning
②
Technology object
⑤
Diagnostics
③
Configuration
Note
For CPU firmware releases V2.2 and earlier, the PTO requires the internal functionality of a
high
-speed counter (HSC). This means the corresponding HSC cannot be used elsewhere.
The assignment between PTO and HSC is fixed. If PTO1 is activated, it will be connected to
HSC1. If PTO2 is activated, it will be connected to HSC2. You cannot monitor the current
value (for example, in ID1000) when pulses are occurring.
S7
-1200 V3.0 and later CPUs do not have this restriction; all HSCs remain available for
program use when pulse outputs are configured in these CPUs.