102BTechnology instructions
9.3 Basic motion control
S7-1200 Programmable controller
342
System Manual, 11/2011, A5E02486680-05
Table 9- 22 Limit frequencies of pulse outputs
Pulse output
Frequency
Onboard
2 Hz ≤ f ≤ 100 KHz
Standard SB
2 Hz ≤ f ≤ 20 KHz
High-speed (200 KHz) SBs
MC V2 instructions: 2 Hz ≤ f ≤ 200 KHz
MC V1 instructions: 2 Hz ≤ f ≤ 100 KHz
1
1
MC V1 instructions support a maximum frequency of 100 KHz.
NOTICE
The maximum pulse frequency of the pulse output generators is 100 KHz for the digital
outputs of the CPU, 20 KHz for the digital outputs of the standard SB, and 200 KHz for the
digital outputs of the high-speed SBs (or 100 KHz for MC V1 instructions). However,
STEP 7 does not alert you when you configure an axis with a maximum speed or frequency
that exceeds this hardware limitation. This could cause problems with your application, so
always ensure that you do not exceed the maximum pulse frequency of the hardware.
1.
Configure a pulse generator: Select the "Pulse generators (PTO/PWM)" properties for a
CPU (in Device configuration) and enable a pulse generator. Two pulse generators are
available for each S7-1200 CPU. In this same configuration area under "Pulse options",
select Pulse generator used as: "PTO".
2.
Add a Technological object:
–
In the Project tree, expand the node "Technological Objects" and select "Add new
object".
–
Select the "Axis" icon (rename if required) and click "OK" to open the configuration
editor for the axis object.
–
Display the "Select PTO for Axis Control" properties under the "Basic parameters" and
select the configured PTO. Note the two Q outputs assigned for pulse and direction.
–
Configure the remaining Basic and Extended parameters.
3.
Program your application: Insert the MC_Power instruction in a code block.
–
For the Axis input, select the axis technology object that you created and configured.
–
Setting the Enable input to TRUE allows the other motion instructions to function.
–
Setting the Enable input FALSE cancels the other motion instructions.
Note
Include only one MC_Power instruction per axis.
4.
Insert the other motion instructions to produce the required motion.