Hello,
It sounds like the Send to CNC command you have created in the Predator Software for this machines needs a "Send Events" object to tell the CNC, you hit the end of the program. \027 or check your existing software for the ascii character and add that to the end of the program line in events.
Also, if you purchased from a dealer, they should support you for this. If you don't have a support dealer, feel free to reach out to us. We are Predator's largest dealer in the USA.
Should have no issues with Siemens 840 controller.
Regards,
Greg Mercurio
Shop Floor Automations
www.shopfloorautomations.com
877-611-5825