search

plcpeople / nodeS7

Node.JS library for communication to Siemens S7 PLCs
MIT License
358 stars 121 forks source link

Packet Timeout due to Fast Acknowledge #44

Open sembaye opened 6 years ago

sembaye commented 6 years ago

Hi, currently i have a problem that due to the lovely Fast Acknowledge a timeout occurs.

See: error org.txt

Until the “onResponse” function, the communication is alright.

I would we should somehow cancel the timer or re-trigger it here: https://github.com/plcpeople/nodeS7/blob/3f70a74e0609f09f32fad394e251dc34406e1486/nodeS7.js#L1088

I tried it out with “clearReadPacketTimeouts” but then further communication was not possible anymore. How can I restart the timer?

plcpeople commented 6 years ago

There are potentially multiple timers, one for each packet that is sent. So I don't think we necessarily want to re-trigger all timers on receiving a fast ack. (Although it could be done.) Does increasing self.globalTimeout (currently hard-coded on line 71) to higher than 1500ms help in your application? If so, maybe allowing this timer to be adjusted when creating a new connection is a valid solution.

I really wish we had an old PLC so I could test with fast ack, but we don't.

sembaye commented 6 years ago

OK, thank you. I have new knowledge about Fast Acknowledge and the entire RFC layer. As soon as I fixed my bug(s), I will inform you about it in the wiki.

ceremcem commented 6 years ago

@sembaye IMHO, You may leave this issue open, as it is not meant to be solved yet. If any of us is unable to find an appropriate PLC and test it or solve the problem, @plcpeople would close it anyways.

sembaye commented 6 years ago

oki doki