Siemens Simatic S7-1500 CPU 1512C-1 PN User Manual page 70

Technology functions
3.2 Pulse generators
Use case
1. Transfer the control for the output to the PWM channel.
2. Set SW_ENABLE, in order that the output can be started.
3. Set the required on-load factor using OUTPUT_VALUE.
4. If necessary, change the period duration (cyclic or once). If you do not change the value,
the period duration from the hardware configuration will be used.
5. With TM CTRL_DQ and SET_DQ set the output from the user program permanently to 1
or 0.
6. Acknowledge any errors that occur using RES_ERROR.
Additional parameters for the output sequence are defined before the start of an output
sequence.
The data record of the parameter assignment is changed in the device configuration in
STEP 7 (TIA Portal) or through WRREC execution.
Control interface parameters
OUTPUT_VALUE
The interpretation of the value OUTPUT_VALUE depends on the set operating mode.
OUTPUT_VALUE is always updated. When an invalid value is detected (outside the
permissible range), the error memory bit ERR_OUT_VAL is set until a valid value is
detected. During the error condition the invalid value is ignored and the PWM channel
continues with the last valid OUTPUT_VALUE. Note that, in the frequency output mode, it is
also possible that no last valid value is available. In this case the pulse output returns the
value 0, i.e. there is no pulse output.
Please note that the on-load factor is not checked in PWM mode. If the on-load factor is
greater than the format permits, the PWM channel uses a ratio of 100 %. 0 % in effect for
values < 0.
SLOT, MODE_SLOT and LD_SLOT
Use these control interface fields if you occasionally change the period duration in PWM
mode before the start of the output sequence or during operation. You can find a description
of the interaction between SLOT, MODE_SLOT and LD_SLOT under Handling the SLOT
parameter (control interface) (Page 71)
SW_ENABLE
If 0 → 1, activate the output sequence.
TM_CTRL_DQ
● If 1, the output is controlled by the PWM channel and generates the pulse sequences
● If 0, the output is controlled directly by the program using the SET_DQA assignments
SET_DQA
● If 1, set the output A to 1, if TM_CTRL_DQ is inactive
● If 0, set the output A to 0, if TM_CTRL_DQ is inactive
RES_ERROR
Resetting the error bit memory ERR_LD in the feedback interface
70
CPU 1512C-1 PN (6ES7512-1CK01-0AB0)
Manual, 12/2017, A5E40898741-AA