How to obtain acknowledgement of simple write to variable using gpascii

[mshaver]

For simple writes to user variables using gpascii, I don’t see any “native” way to get an acknowledgement from the PPMAC that it received the communication and understood it. If it doesn’t understand the command then I do get an error message, but I don’t see a native way to get a positive response.

 

IE; if I send command “DistX=100” I get no acknowledgement from the PPMAC that it's even out there.

I don’t see any way to “turn on” such a response. I’ve used the echo command for other responses but it does not address this issue.

 

I did demonstrate that sending the command “DistX=100 DistX” does work as expected and the PPMAC returns either “100” or “DistX=100” depending on the echo settings.

 

How do others accomplish this? Have I overlooked something that will turn on an automatic response or acknowledgement of “DistX=100”?

mshaver@pekoprecision.com

[steve.milici]

This is described in the "Power PMAC User's Manual" in the section "Talking to Power PMAC" starting on page 17. In general unless there is an error Power PMAC responds only with a CR, CTRL-F sequence after receiving a CR terminated command.

[MClement]

We are dealng with the same problem where commands that dont return anything are hard to queue and dequeue. We also used the trick of adding P0 to each command to force a return from ppmac.

[mshaver]

Good idea!

[steve.milici]

All PPMAC CR terminated commands will be replied with the ACK or CTRL-F character. If there is a text response each line of response is terminated with a CR and the final line will respond with the CTRL-F. If there is an error the BELL character or CTRL-G is returned.