Landis & Gyr IP-Telemetry problem

sdg.marinusvz
2024-06-13 10:55

This message was transcribed from a support call

Hi, I have a problem reading in my Landis & Gyr meter (IEC61107) over an IP-Telemetry modem.

Please help.

On the Meter Read log, it says:
Communication error
OM.util.ap: OM Read timeout

sdg.marinusvz
2024-06-13 10:57
Last Edited 2024-06-13 11:07

I see the comunication attempt times out in the middle of receiving a packet:

10:27:11.938 P.01(020610103000)(0004)(30)(8)(1.5.0)(kW)()(kW)(5.5.0)(kvar)()(kvar)()(kvar)()(kvar)(9.5.0)(kVA)()(kVA)

10:27:14.132 (006.28)(000.00)(002.65)(000.00)(000.00)(000.00)(006.83)(000.00)2024-06-13 10:27:15,ERROR,lgz.prp,SDG.MDAS.SDGInputLGZ,.askInfo: OM.util.ap: OM Read timeout;,'66315999'

IPT is a much more complicated way to communicate, it has sub-channels, so there are a lot of link management control messages going back and forth over the cell phone data link, over and above the data from and to the meter. So unless your cell phone signal is really good, the chances for something to go wrong is a lot higher than with a simple Generic APN Modem connection.

I see your start window size is too big for IPT (43200000ms)
That is on your Advanced Meter Settings screen
It is the amount of data for the profile that we ask for at a time.

that is 12 hours

I'd say, lets divide that by 4

I changed it to 10800000

ok lets wait for this attempt to finish?. then check the next attempt...

sdg.marinusvz
2024-06-13 11:02

Oky no problem

sdg.marinusvz
2024-06-13 11:02

BCC not correct, asking for day's readings again

ok, it seems like it came through right the second time. In the first reply there was a

(00.00)<CR>

that should have been

(000.00)<CR>

so it seems like the first time it dropped a byte in the reply

however we picked it up and asked for the period again. And now the time we ask for is progressing nicely...

sdg.marinusvz
2024-06-13 11:03

Oky what could be the reason for it dropping a byte

sdg.marinusvz
2024-06-13 11:04

corruption of communication channel.

There could be many reasons for the corruption of the communication channel. For instance, a cable, electromagnetic interference on a communication cable (e.g. in HV situations with mutidrop - try changing straight telephone cable for twisted pair), unreliable cell phone signal, and probably many other things?.

In my opinion, if you read the meters over a Generic APN modem, instead of IPT, the burden of exact communication framing on the cell phone data stream would be much alleviated, and the communication would be much more tolerant of bad signal.

ok great, you got a partial reading. Just re-read repeatedly, and it should all come in.

sdg.marinusvz
2024-06-13 11:04

for the partial reading in order for us to get success does that mean we need to do repeated reads, or is there something we must do in MDUS to get full readings and not partial readings

sdg.marinusvz
2024-06-13 11:05
Last Edited 2024-06-13 11:06

I think this byte was dropped between the meter and the modem, since IPT does framing of sub-stream data packets, it implies that the framing worked without dropping the stream, and therefore the byte was lost before the modem framed the data packet. So it is not just the cell phone data stream that is stressed with IPT, but even the comms stream just between the L&G meter and L&G modem, in my opinion.

So, switching to a Generic APN modem would relieve the stress on the communications channel as a whole, not just within the cell phone network

With a partial reading, typically the 'Last Read Up to Date & Time' should have advanced. Once it has advanced to the current time, the meter is effectively 'read in' fully.

does that answer your question?

(we got another 'BCC not correct, asking for day's readings again' just now, by the way..)

Last time, you said you're going to read these over an APN. What happened with that?

sdg.marinusvz
2024-06-13 11:15

we ended up getting progress with our sim cards (pay as you go public apn internet sim cards), not the private apn sim cards, so we decided to carry on with our sim cards on the IEC, not the DLMS. On many sites with the E650s, we're getting partial readings with it. So we're getting data, but it is just that partial reading, we're not getting the full reading.

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