Raspberry Pi EMS Value Stream

Question

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

jsaynava · Accepted Answer

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.

chiwatashi · Answer

The steps seems to correct, so could you upload the wsems, and lua logs?

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