Dripfeeding Checklist for Predator DNC

Dripfeeding Checklist

Should anyone experience dripfeeding issues, the following dripfeeding checklist should be reviewed, discussed and implemented when appropriate:

1. Use Ethernet vs. serial when supported by the CNC.
2. Use error correcting protocols when supported by the CNC, refer to the section below.
3. Enable Predator DNC's ServerSafe™ option when the Predator PC is located on the shopfloor.
4. With serial communications, reduce serial hardware buffer size to the smallest possible buffer setting.
5. With PC serial ports reboot the PC after setting the smallest possible buffer setting.
6. With serial communications, review flow control settings in the CNC, cable and Predator DNC.
7. With older CNCs, reduce the number of CNC programs stored within the CNC memory.
8. Review the USB to Serial device, many do not work reliably, consider upgrading to the Predator USB Grizzly Cable Bundle kit.
9. Review PC power savings options and disable energy saving options.
10. Review PC Ethernet card power savings options and disable engery saving options.
11. Review PC Ethernet duplex options and enable full duplex.
12. Review the firmware versions of all serial hardware.
13. Review the device driver versions of all serial hardware.
14. Review the firmware versions of all Ethernet hardware.
15. Review the device driver versions of all Ethernet hardware.
16. Review Ethernet packet losses.
17. Review the Ethernet and serial cabling.
18. Review the CNC programs and make sure GOTOs, DO WHILE, IF THEN and other branching logic is not present.
19. Review the CNC programs and make sure that sub programs and sub program calls are not present.
20. Enable Predator DNC's automatic sub program processing for dripfeeding.
21. Review Predator DNC's version 11 history for new dripfeeding features and bug fixes.
22. If Predator CNC Editor displays a "Bytes: Written 0" error upgrade to a reliable USB to Serial adapter, consider the Predator USB Grizzly Cable Bundle kit.

Root causes of dripfeeding issues are commonly one or more of the above items. Predator support personnel are available to discuss and help implement improvements to the dripfeeding process.

Advanced Protocols that support dripfeeding

The following protocols are all recommended for dripfeeding vs. a simple ASCII file transfer. It is very common to dripfeed with simple ASCII file transfers that unfortunately do not support error correction.

Testing Dripfeeding

Testing dripfeeding can be done to troubleshoot and restore confidence in dripfeeding. Refer to the following:

1. Test dripfeeding by dry running test CNC programs with sequence numbers on every line
2. Test flow control by pressing the feed hold button to pause dripfeeding and the cycle start button to resume
3. Test by swapping out hardware components
4. Test dripfeeding by simplifying the process
5. Test using a PC next to the CNC

Fixing Dripfeeding Issues

Fixing a dripfeeding issue should always start with the following changes:

1. Reduce the buffer size within the device driver to the smallest setting
2. Add a 1 millisecond send line delay within Predator CNC Editor or Predator DNC
3. Add a 1 millisecond send character delay within Predator CNC Editor or Predator DNC
4. Change flow control from software to hardware

Predator support personnel are available to discuss and help implement improvements to the dripfeeding process.

More Self Help Articles

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