Mqtt and dnp question about missing data

do either of these solutions, the mqtt modules available from cirruslink and the dnp driver from ignition, support back-filling historical data into Ignitions tag historian?

For instance, I have a cellular connection to a site. That cellular connection may go down for a few hours. Do either of these options back-fill the historian upon re-establishment of the cellular connection?

Hello.

Did you get an answer about this point (especially concerning MQTT) ?

I don’t know if this is what your looking for, but let me try to explain what I know. (You may also want to check with CirrusLink as Mr Arlen Nipper is the MQTT expert.

I think this would all depend on how you have the Publisher/Broker/Subscriber setup and running. Does the MQTT data get published thru the cellular connection to a Broker? (If so when the connection is down the Broker is no longer being updated!)

But if the MQTT data is published to a broker, before the cellular connection - this data will be buffered in the Broker, so as soon as the connection is re-established the subscriber will collect all buffered data.

But I also believe that certain “Edge of Network” devices can be purchased with and setup with different degrees of buffering.

Once again talk with Cirrus Link those people know MQTT.

Yes, I’ve successfully back-filled historical data into Ignition’s tag historian using Cirruslink’s MQTT engine module connected to a Redigate110e.

This one is interesting to me as I’m also doing a similar thing and store and forward kind of set up crossed my mind.

So I have numerous Raspberry Pi’s in the field, Some talking to Siemens PLC’s and some with Arduinos attached using various sensors. The plan is to use Node Red to handle all that business.

I was going to set up a broker in the cloud and I’m currently playing with Azure but having issues with the SAS tokens, The Pi’s communicate to the world via a local Cell modem on the site. That’s where the ‘store and forward’ comes in as with it being a cell connection anything could happen and we still want to log the data should that machine be taken further away then the router coverage.

From the above it seems that storing a local version of say Mosquito on the Pi as a broker would be better as the broker does indeed ‘store and forward’?

HiveMQTT has a demo broker available http://www.mqtt-dashboard.com/ for any one playing around with MQTT. I’ve successfully subscribed to some of the published articles in ignition using the cirrus MQTT Engine.

The server URL is tcp://broker.hivemq.com:1883 then set up what articles you want to subscribe to in the Name Spaces then they appear in the designer like Tags to use.

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@Scott.Hann Correct me if I am wrong, but in your example, isn’t the Redigate Edge of Network device in charge of the Store and Forward?
MQTT transmission does have the capability to do SNF:
https://www.cirrus-link.com/mqtt-modules-ignition/#mqtttransmission

Cheers,

Oscar.

You are definitely correct Oscar, cirrus-link MQTT transmission can Store and Forward to an Ignition cirrus-link MQTT distributor server, or a 3rd party MQTT server. My example features how a when a 3rd party MQTT tag provider stores and forwards to cirrus-link MQTT engine, the engine will back fill the historical data. If you used cirrus-link MQTT transmission to SNF to the cirrus-link MQTT engine, I expect it will back fill historical data equally well, though I’ve not personally tested that setup.

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If the published message used a QOS 3, it should store the message until its delivered and verified ?

Are all the messages date and time stamped so once it publishes the messages you know in what order and what relates to what for processing ?