"General Information on the PTO
Once running the PTO will continue to generate pulses until all pulses have been generated or the PTO:0/EH (Enable Hard Stop) bit has been activated.
Once the EH bit is set the instruction will generate a PTO error of 1 (hard stop detected). In order to clear this error the PTO instruction must be scanned on a false rung of logic, and the EH bit must be off.
To change the Total Output Pulses Generated in a working program a new value can be moved into PTO:0.TOP by using the MOV command. Important Note: Once the PTO has been initiated and is generating pulses a new TOP value will not take effect until the PTO has either completed generating pulses and has been restarted or has been Hard Stopped using PTO:0/EH bit and been restarted."
Based on the above, I would say it is not possible. You may want to experiment.
Regards,