API chart endpoint always returning empty array

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Tommaso Girotto asked Feb 18, '22

API chart endpoint always returning empty array

https://vrmapi.victronenergy.com/v2/installations/<INSTALLATION_ID>/widgets/Graph?attributeCodes[]=OV1&attributeCodes[]=OV2&attributeCodes[]=OV3&attributeCodes[]=S&attributeCodes[]=iST

is always returning empty array

{ "success": true, "records": { "data": { "20": [], "21": [], "22": [], "40": [], "412": [] }, "meta": { "20": { "code": "OV1", "description": "Output voltage phase 1", "formatValueOnly": "%.1F", "formatWithUnit": "%.1F V" }, "21": { "code": "OV2", "description": "Output voltage phase 2", "formatValueOnly": "%.1F", "formatWithUnit": "%.1F V" }, "22": { "code": "OV3", "description": "Output voltage phase 3", "formatValueOnly": "%.1F", "formatWithUnit": "%.1F V" }, "40": { "code": "S", "description": "VE.Bus state", "formatValueOnly": "%s", "formatWithUnit": "%s" }, "412": { "code": "iST", "description": "Inverter state", "formatValueOnly": "%s", "formatWithUnit": "%s" } } }}

despite everything working fine both electrically and in the VRM dashboard.

What am I doing wrong? @Teun Lassche any advice?

VRM api

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Kristo Lippur (Victron Energy Staff) commented · Feb 18, 2022 at 06:13 PM

Hi Tommaso,

You need to specify the instance (device) for which you are requesting the data. You can find this in the device list as "VRM instance". Pass it as "instance=XXX" in the query string.

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Kristo Lippur (Victron Energy Staff) answered · Feb 22, 2022 at 01:07 PM

Hi!

The attributes you are requesting are provided by the VE.Bus. For example, for installation 148798 you can get the OV1 and S attributes using instance ID 276:

/v2/installations/148798/widgets/Graph?attributeCodes[]=OV1&attributeCodes[]=S&instance=276

For the solar chargers, different attributes are used. For example, the solar charger voltage and current are attributes ScV and ScI respectively. You can request these with the solar charger instance ID:

/v2/installations/148798/widgets/Graph?attributeCodes[]=ScV&attributeCodes[]=ScI&instance=0

For both of these requests, you should see data returned as expected. You can find the right attributes to use for the solar chargers in the API documentation, https://docs.victronenergy.com/vrmapi/overview.html#retrieve-diagnostic-data-all-current-installation-data

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Answer 1 · 2022-02-21T11:21:07Z

Tommaso Girotto answered · Feb 21, 2022 at 11:21 AM

Hi @Kristo Lippur (Victron Energy Staff) , thanks for the reply.

I have tried with all the instance numbers I have found in the VRM dasbhoard device list, but the result is always empty (just to be clear, I can see that instance numbers are usually integers lower than 1000). The devices I have tried to query are solar chargers, pv inverters and battery monitors, and I have tried both with start/end query strings and without (in s and ms formats). Do you have an example url as reference?

Thanks for the support.

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