Siemens S7-1200 System Manual page 442

Technology instructions
9.3 Motion control
A signal board (SB) expands the onboard I/O to include a few additional I/O points. An SB
with two digital outputs can be used as pulse and direction outputs to control one motor. An
SB with four digital outputs can be used as pulse and direction outputs to control two motors.
Built-in relay outputs cannot be used as pulse outputs to control motors. Whether you use
onboard I/O or SB I/O or a combination of both, you can have a maximum number of four
pulse generators.
The four pulse generators have default I/O assignments; however, they can be configured to
any digital output on the CPU or SB. Pulse generators on the CPU cannot be assigned to
SMs or to distributed I/O.
Note
Pulse-train outputs cannot be used by other instructions in the user program
When you configure the outputs of the CPU or signal board as pulse generators (for use with
the PWM or motion control instructions), the corresponding output addresses no longer
control the outputs. If your user program writes a value to an output used as a pulse
generator, the CPU does not write that value to the physical output.
Table 9- 22 Maximum number of controllable drives
Type of CPU
CPU 1211C DC/DC/DC
AC/DC/RLY
DC/DC/RLY
CPU 1212C DC/DC/DC
AC/DC/RLY
DC/DC/RLY
CPU 1214C DC/DC/DC
AC/DC/RLY
442
①
PROFINET
②
Pulse and direction outputs
③
Power section for stepper motor
④
Power section for servo motor
The DC/DC/DC variants of the CPU S7-1200 have onboard
outputs for direct control of drives. The relay variants of the
CPU require the signal board with DC outputs for drive
control.
Onboard I/O;
No SB installed
With Without
direction direction
2 4
0 0
0 0
3 4
0 0
0 0
4 4
0 0
With an SB
(2 x DC outputs)
With Without
direction direction
3 4
1 2
1 2
3 4
1 2
1 2
4 4
1 2
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
With an SB
(4 x DC outputs)
With Without
direction direction
4 4
2 4
2 4
4 4
2 4
2 4
4 4
2 4