How to display negative values from a Signed Integer

Hi every one, great to be part of this great product community!!! I’m new here and I got problem with negative value coming from InfluxDB. I searched since 2 days on Internet and nobody seems to have this problem. I read temperature through a sensor and when the temperature goes below 0C (Welcome to Quebec) I get 0xFFFF value that represent -1C. How do Grafana deals with it, since it is interpreted as a non signed integer (65535)

Thanks to guide me,

Have a wonderful day!!!


Hey @alsargent, any ideas? I would help, but I don’t know what a signed integer is. :slight_smile:

@dominiquegrenier Let me see if I might help. First, which versions of InfluxDB and Grafana are you using? Also, how are you sending the data into InfluxDB (Telegraf, client library, something else…)?

Hi, thanks for your support!
I’m using Chirpstack to send data to InfluxDB (v1.8.3). Am I wrong if I say that Grafana ABSOLUTELY NEEDS to have 64-bit floating-point numbers as default numerical. If less than 64 bits, normal to lost real value. Is there a way to cast values, because with Lorawan, payload is very limited…

Thanks for that info. First, a bit of background: I’m with InfluxData and only know the basics of Grafana. I can say that InfluxDB 1.8 supports signed integers up to 64 bits.

So, in theory you should be okay in terms of data storage. Have you done a query against InfluxDB to confirm that your data values are as expected, and that negative numbers are showing up correctly in the query results?

Hello, yes, my data in InfluxDB is as expected (0xFFFF for -1C) on signed my 16 bits system.
But Grafana see it as 65535 (16 bits non signed) . That’s why I’d like to cast it to 64 bits format.

@dominiquegrenier Thanks for that info. What version of Grafana are you using?

@ryanmckinley Any thoughts on what Dominique should do here? More context in the thread.