question

sungrid avatar image
sungrid asked

Update interval of Victron output node in Node-RED flow

Hi,

I'm sending all data from NodeRED to the InfluxDB cloud. Because of costs, I need to reduce the update interval to 30 secs. Is there any way to configure it? (config file which survives Venus OS update)

Thx

Node-REDmodifications
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4 Answers
Dirk-Jan Faber (Victron Energy) avatar image
Dirk-Jan Faber (Victron Energy) answered ·
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sungrid avatar image
sungrid answered ·

This is not useful because messages are received randomly. Some every xy seconds, some when values are changed. If I limit to for example 100 messages per 30 seconds, first 5 seconds, some fields will be updated several times and some never, and another 25 seconds will be silent. I need a batch time-based function (as implemented in nodered), but with averaging every field in meantime.

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Dirk-Jan Faber (Victron Energy) avatar image
Dirk-Jan Faber (Victron Energy) answered ·

In that case I would store the irregular updating value to a context. E.g. flow.myvalue.

And have an inject node running every 30 seconds that reads flow.myvalue into msg.payload and passes that to the influxdb node. Something like:

1670764913124.png

Not sure what you mean by averaging every field in the mean time though. You might want to take a look at https://flows.nodered.org/node/node-red-contrib-rate-avg for that.

See https://gist.github.com/dirkjanfaber/188d5abb4dc134b6d31987783739bae3 for the flow of the above example.


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sungrid avatar image
sungrid answered ·

I would have to configure the change node for each field separately. In addition, Victron only sends payload and the field name is in msg.topic. I solved this using node-red-contrib-calculate

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Instead of using a change node, you can also use a simple function doing something like:

global.set(msg.topic.replace(' - ', '').replace(/\//g, '.'), msg.payload);
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Related Resources

Webinar Part 1 - Intro to Node-Red

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Webinar Part 3 - Advanced example

Victron Node-RED for dummies guide by Fideri

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Venus OS Large (Node-RED) manual

Victron Node-RED github readme

Victron Node-RED custom nodes docs

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