[SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by jonbev on Fri, 15/03/2013 - 12:58

I'm using the emonTx_CT123 code only modified to add two temperature sensors. I have one CT on the main supply to the house.

When the electricity usage goes above about 4.5kW I only seem to get one ready per minute instead of the usual one every five seconds. I also get no temperature readings at the same time.

I'm guessing it may be interference with the wireless signal cause by the higher power usage? I have moved my PI closer to the emontx but it has made no difference.

My other thought was that it could be power supply related, I'm using and old blackberry usb charger to power the board.

Any suggestions?

Cheers

Jon

Re: [SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by Robert Wall on Fri, 15/03/2013 - 13:21.

Thoughts:

Have you tried writing the values to the serial port and monitoring it locally?
Have you got the correct addresses for your temperature sensor?
I don't think it is the higher power per se,
How did you modify the PayloadTX to accommodate the temperatures? You're only allowed 66 bytes, and they need to be signed integers. Normally we multiply the decimal temperature by 100 and send it as a signed integer, then multiply by 0.01 in emoncms to restore it.
Problems have been reported with noisy USB power supplies. If it works using the power via the programmer, that would be a good indication of that.

Re: [SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by jonbev on Fri, 15/03/2013 - 13:59.

Thanks for the quick response.

I probably wasn't very clear - the temperatures work all the time apart from when the power usage is high.

Have a look here - http://bev.csdl.biz/emoncms/jonbev&id=1 if you zoom in on yesterday at about 6:30am there is a good example. No temps between 6:30 and 6:45 and only 15 power measurements in the same time period.

Re: [SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by Robert Wall on Fri, 15/03/2013 - 15:07.

Have you checked the mains voltage into the USB power supply, and the 5 V out, when you're drawing > 4.5 kW. You might just have a loose connection in your house wiring that needs prompt attention.

What about the power supply to the Raspberry Pi that receives the data?

If not that:

There's nothing inherent in the code in the emonTx that I know of that could cause that. So the starting point is, Is the main loop being executed at the correct rate - every 5 s or so? What values are in PayloadTX prior to transmission?
(If those are correct, an easy way to continue testing without wasting power: temporarily overwrite the genuine power with '5000' or some similar value that is known to cause the problem).

How are you receiving the data and processing it - is that where it's falling over? Are you not receiving the data, or are you receiving incorrect values that are being rejected?

Re: [SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by jonbev on Fri, 15/03/2013 - 15:42.

OMG what an idiot!

I installed the event module a while back and set up a rule to email when power > 5000. I guess 1 minute is the timeout on the send email process.

I have removed the rule now.

Thanks for your help Robert.

Re: [SOLVED] Only getting 1 reading every minute when over 4.5kW

Submitted by Robert Wall on Fri, 15/03/2013 - 16:25.

Rule no. 1: Look for the most simple and obvious explanation first.

[Face - palm?] Don't worry too much, I've got the baseball cap and the T-shirt!

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