Raspberry Pi EMS Value Stream

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Hello all,

We have established Raspberry Pi connection to Thingworx server with Edge microserver and Lua Script Resource and the property values update correctly. (https://developer.thingworx.com/resources/guides/thingworx-raspberry-pi-quickstart)

How can we get the values to be logged to a value stream?

Value stream is defined and connected to the PiThing. Properties from RaspberryPi are bind and marked as "persistent" and "logged" (for example cpu_temperature). Initial record to the value stream is created when LSR is started but after this no new records are added. The initial record with the original time stamp just gets a new value (eg. cpu_temperature). I am querying the value stream with "QueryPropertyHistory" service.

What are we missing here?

Any help would be appreciated.

ThingWorx 8.4.2-b2151

J

jsaynavaAnswer

1-Visitor

Hi,

The LSR does indeed send the data with the same timestamp everytime.

I digged around the lua files and modified file "/EMS/microserver/etc/thingworx/lua/utils.lua" so that it adds the os.time() instead of prop.time. This way the timestamp updates and data gets logged to the value stream.

function toVariantVTQ(prop)
local t = {}
local name = prop.name or "value"
t['value'] = { baseType = prop.baseType, value = prop.value } -- variant format for JSON
-- t['time'] = prop.time or os.time() * 1000
t['time'] = os.time() * 1000 or os.time() * 1000
t['quality'] = prop.quality or "UNKNOWN"
return t
end

I'm not sure whether this is intended behaviour of the LSR or not but at least now it works.