May 5, 2020
I created a 'React' with "No data check". I like to use it to notify me when the channel does not get any data. In particular I like to check if a device looses Internet.
It kind of works. I get the notifications. However, I either get to many or only one.
The situation is that the device might go offline for hours. I like find out within 15 minutes if this happens. I like to receive just 1 notification in this case. Then after many hours the device might go online again and starts submitting data again. Now if the device goes offline AGAIN then I like to receive ANOTHER notification.
There are only two options available:
1. Run action only the first time
2. Run action each time
The first wont work as I will only get a notification the very first time the channel stops receiving data (but not the second time the device goes offline).
The second wont work either because it keeps sending me notifications (and flooding my phone!) until the channel starts receiving data again.
Is there a way to have a third option "3. Run action once whenever data stops"? (perhaps with mathlab analytics?) or could this be a generic option?
May 5, 2020
Well, i got it working. After a disconnect I get the message. Thereafter I connect again and start submitting data. If I stop submitting data within say 1-5 minutes then I wont get a ''No Data Check" even if I wait for hours. However if i submit data for a longer time period and then stop transmitting then I do get a 'No Data Check' message. This should be documented how many data points and for how long need to be submitted so that another 'No Data Check' is triggered on the next disconnect as well.
May 5, 2020
Found out what's going on:
Create a React that is set to check ‘every 10 minutes’ for ‘no data in the last minute’ and to trigger the action only once (the first time no data is received). My script is submitting data every 15 seconds to the channel.
The time is given in ‘minutes past the hour’. ThingSpeak performs a ‘No Data Check’ (NDC) in discrete 10 minutes intervals starting with 10 mins past the hour.
15 mins - send 1 packet. End Transmission.
20 mins - React NDC is triggered.
21 mins - send 1 packet. End transmission.
30 mins - React NDC is NOT triggered.
Deleting and re-creating the same React and running this:
15 mins - send 1 packet. End transmission.
20 mins - React NDC is triggered
29 mins - send 1 packet. End transmission.
30 mins - React NDC IS triggered.
The documentation says that in both cases a ‘No Data Check’ should be triggered but the first case doest not trigger an NDC.
It appears that the ThingSpeak backend does not reset the React unless the ‘negative’ of the logic
becomes true (e.g. “if received data in last minute then reset React”).
However, the documentation says that the React is reset when new data received - which is not is happening.
March 7, 2017
Thank you for your feedback and diligent testing and reporting. I will look into improving the documentation.
FYI, MATLAB answers is the preferred location for ThingSpeak Community support.
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