Thingspeak: message limit, update limit and bulk updates

Question

I am looking at ThingSpeak for logging sensor data.

I would like to log three different variables at a frequency up one datapoint per second. This would be 86400 samples per day or 259200 values per day.

The thingspeak "pricing" page says that on free accounts:

1. "The number of messages" is limites to ~ 8200 per day.
2. "The message update interval" is limited to >15 seconds.

My question is: for ThingSpeak, what counts as a "message"? Is it each http request or each sample?

I.e. can I collect my samples for, say 120 seconds, and post them as a bulk update? This would be only 720 http requests per day but still 86400 samples per day. Would this fit into the ThingSpeak limits?

Answer 1

Accorinding to this post, API Rate Limit by on the ThingSpeak API Forum, one message means one HTTP request and there is no limit about how many fields do you want to update with that request or about the size of the payload.

Brief of the question:

I have a channel for temperatures with 4 fields mapped to 4 thermal probes [...]

• Do I need to wait 15 seconds between POSTs to each field?

• Do I need group all 4 sensor readings into a single POST request?

• Are my assumptions correct or should separate sensors really be on separate channels etc…

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The answer:

You can send all your data for the 4 fields as one POST, or you can make a separate channel for each of your sensors.