Re: [Ext] Re: Room temperature and humidity monitoring with EPICS?

[Matt Newville via Tech-talk <tech-talk@aps.anl.gov>]

Hi Jesse, 

Sorry for the delay.   What I do is fairly simple.  For each sensor, I load a small record into a softIOC with

        dbLoadRecords("esensor.db","P=13IDE:,Q=Esensor")

in the startup script and with the "esensor.db" of (also attached):

####

# record used for Esensor temperature, humidity sensors
record(ai,"$(P)$(Q):TempF") {
           field(DESC, "Temperature (F)")
           field(VAL,  "0")
}

record(ai,"$(P)$(Q):TempC") {
        field(DESC, "Temperature (C)")
        field(VAL,  "0")
}

record(ai,"$(P)$(Q):Humid") {
          field(DESC, "Humidity (percent)")
          field(VAL,  "0")
}

record(stringin, "$(P)$(Q):TimeStamp") {
           field(DESC, "Timestamp of last update")
           field(VAL,  "")
}

####

Then, I run a Python script (attached) to read the sensor (over plain HTTP), parse the results, and push to PVs.  The script handles both older Esensors that send data as XML, and newer ones that send JSON data.  You could probably put that script inside procServ or something like that but I just have it running as a simple background script.  

--Matt

On Fri, Nov 10, 2023 at 4:15 PM Jesse Hopkins <jhopkins1@iit.edu> wrote:

Hi folks,

Thanks to everyone who shared what you're using! I think what Matt or Pierrick suggested are right in line with what I had in mind.

The price point on something with temperature and humidity is a bit better from the Esensors that Matt shared, so that's where I'm leaning. Matt, if you'd be willing to share your python script that would be great. I was looking at the EM32-Xe, because the display would be a nice feature to have. Have you used that one?

All the best.

- Jesse

----
Jesse Hopkins, PhD
Deputy Director
BioCAT, Sector 18
Advanced Photon Source

On Fri, Nov 10, 2023 at 12:37 PM Matt Newville <newville@cars.uchicago.edu> wrote:

Hi Jesse, 

We have a few of the Esensors temperature/humidity sensors in our hutches, including the EM32-Le  https://eesensors.com/products/websensors/environmental-monitor-sensor.html 

These have a simple magnetic mount and an ethernet port.  They provide a simple web app to read the temperature and humidity. But, there is also an HTTP API to get XML or JSON (depending on the generation of the sensor) with the data. Fetching and reading those values and putting them into Epics PVs is pretty straightforward.  I'd be happy to share the Python script we use to read multiple meters and put them into PVs so we can monitor temperature and humidity and put those values into metadata.

--Matt

On Fri, Nov 10, 2023 at 11:47 AM Jesse Hopkins via Tech-talk <tech-talk@aps.anl.gov> wrote:

Hi folks,

We're looking for a way to monitor humidity and temperature in our experimental enclosures (beamline hutches), with readings that we can access via EPICS. I'd prefer something ethernet based, and low cost is always good. I strongly suspect folks in the EPICS community have already done this in a variety of ways, though I wasn't able to turn anything obvious up in a search. 

Does anyone have a good solution that you're using?

I suspect that if there's nothing else out there I could just buy some analog input boxes (e.g. LabJack or Measurement Computing) and hook up a couple of sensors, but I'm hoping there's a better/cheaper solution.

All the best.

- Jesse

----
Jesse Hopkins, PhD
Deputy Director
BioCAT, Sector 18
Advanced Photon Source

--

--Matt Newville <newville at cars.uchicago.edu> 630-327-7411

--

--Matt Newville <newville at cars.uchicago.edu> 630-327-7411

Attachment: esensor.db
Description: Binary data

#!/usr/bin/env python
import requests
import time
import json
import xml.etree.ElementTree as ET
from epics import get_pv

class ESensor:
    """ read Esensor data, push to Epics PVs"""
    def __init__(self, label, url, prefix, format="xml"):
        self.label = label
        self.url = url
        self.prefix = prefix
        self.format = format

        self.tempf_pv = get_pv(f"{prefix:s}:TempF.VAL")
        self.tempc_pv = get_pv(f"{prefix:s}:TempC.VAL")
        self.humid_pv = get_pv(f"{prefix:s}:Humid.VAL")
        self.timestamp_pv = get_pv(f"{prefix:s}:TimeStamp.VAL")

        self.tattr = "tm0"
        self.tunit = "tun0"
        self.hattr = "hu0"
        self.reader = ET.fromstring
        if format == "json":
            self.tattr = "tmp"
            self.hattr = "hum"
            self.tunit = "tun"
            self.reader = json.loads

    def getval(self, source, attr, force_float=True):
        if self.format == "xml":
            try:
                val = source.find(attr).text
            except:
                val = "-1"
        elif self.format == "json":
            try:
                val = source.get(attr, -1.0)
            except:
                val = "-1"
        if force_float:
            try:
                val = float(val)
            except:
                val = -1.0
        return val

    def read(self):
        resp = requests.get(self.url, timeout=0.25)
        tdat = self.reader(resp.content.decode("utf-8"))

        tunt = self.getval(tdat, self.tunit, force_float=False)
        tval = self.getval(tdat, self.tattr)
        hval = self.getval(tdat, self.hattr)
        return tval, tunt, hval

    def update(self):
        tval, tunit, hval = self.read()
        if tunit in (0, '0', 'F'):
            tval_f = tval
            tval_c = (tval - 32)*5.0/9.0
        else:
            tval_c = tval
            tval_f = (tval_c * 9.0/5) + 32
        tval_f = float("%.3f" % tval_f)
        tval_c = float("%.3f" % tval_c)
        hval   = float("%.3f" % hval)

        if self.tempf_pv.connected:
            self.tempf_pv.put(tval_f)
            self.tempc_pv.put(tval_c)
            self.humid_pv.put(hval)
            self.timestamp_pv.put(time.ctime())
            print(time.ctime(), self.label, tval_c, hval)

#
if __name__ == '__main__':

    esensors = [ESensor("13-ID-E", "http://164.54.160.168/sensorLogUpdate.xml";, "13IDE:Esensor", format="xml"),
                ESensor("13-ID-C", "http://10.54.160.76/status.json";, "13IDC:Esensor", format="json"),
                ]

    while True:
        try:
            [e.update() for e in esensors]
        except:
            pass
        time.sleep(0.5)