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rscada / libmbus

Meter-bus library and utility programs
http://www.rscada.se/libmbus
BSD 3-Clause "New" or "Revised" License
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Hardcoded timeout not sufficiently long #121

Closed mpseybold closed 6 years ago

mpseybold commented 7 years ago

libmbus-0.8.0: the timeout should be a CLI parameter.

the hardcoded, default timeout of mbus-serial-.... is not sufficiently long for some meters (scanning and receiving) Tested with the PW20 M-Bus Master from Relay and the water meter module https://messhelden.com/shop/m-bus-modul-fuer-wasserzaehler/

The same hardware constellation works using the bulky java mbus library: https://www.openmuc.org/m-bus/

THX for your efforts!

lategoodbye commented 7 years ago

Those timeouts are calculated based on the M-Bus Spec, so force the user to specify isn't a nice solution.

Beside the fact the 0.8.0 release is pretty old, what makes you sure that the issue is the wrong timeout? Which commands of libmbus did you use? What was the output? Did you use a USB to serial adapter?

mpseybold commented 7 years ago

Thx for the quick reply. The Setting: Raspberry Pi B+ <=> FTDI USB to RS232 <=> Relay PW20 <=> Modularis M-Bus Module https://www.wehrle.de/en/metering/remote-reading/modularis-modules/ The meter is directly connected to the mbus master - wire length is not the issue.

I used the binary mbus-serial-scan and did not find a slave on any primary address. I used the script read-meter.sh from jMBus and did not find a slave on any primary address, too.

However, jMBus allows to overwrite the default scan timeout of 1000ms using the -t switch. -t 2000 did successfully discover the meter. The same for read-meter.sh , which only succeeds after overwriting the default 500ms timeout with -t 2000.

I didn't manage to try the current master of libmbus tough. The configure.ac file was not compatible with my GNU Autoconf version 2.69 :(

lategoodbye commented 7 years ago

Okay, at which baudrate is the Modularis M-Bus Module? Do you have the issues with autotools from Raspbian?

mpseybold commented 7 years ago

The meter runs on 2400 bauds.

Yes, it's Raspbian Jessie...okay. the INSTALL notes are VERY misleading. They do not work at all. One needs to call ./build.sh instead -- thats all... I'll let you know ASAP how the timeout behaves on the current master.

lategoodbye commented 7 years ago

I will try to find timeout values which should fit also in USB to serial adapter cases (common case nowadays).

lategoodbye commented 7 years ago

@ree2k I adjusted the timeouts in this branch, please try:

https://github.com/rscada/libmbus/tree/serial-timeout

mpseybold commented 7 years ago

sry for the late reply. i) I did not use the CLI interface properly. Both, 0.8.0 and the master, succeed in scanning via the USB-RS232 Adapter, if set up with the correct baud rate.

ii) However, requesting data from the Modularis module still times out ( using the correct baud rate). Issuing the same CLI command right after the first attempt timed out does in fact retrieve the m-bus telegram. This is true for 0.8.0. and the current master.

iii) I will try your branch later today. Thx already.

lategoodbye commented 6 years ago

I assume this isn't an issue anymore.

mpseybold commented 6 years ago

Yes, it's not an issue anymore. The current master works quite nice with a recent debian stretch and kernel.

My weird observation was somehow a mix of not properly using the library, old kernel usb tty drivers and the automatic baudrate negotiation behaviour of the modularis module. Sry for the inconvenience and thx again for the branch.