# OPC UA: I can't read variable assigned
**URL:** https://discourse.nodered.org/t/opc-ua-i-cant-read-variable-assigned/29926
**Category:** General
**Created:** [11 July 2020 23:31 UTC](https://discourse.nodered.org/t/opc-ua-i-cant-read-variable-assigned/29926 "2020-07-11T23:31:49Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@abedgarr](https://discourse.nodered.org/u/abedgarr)
#### Post date: [11 July 2020 23:31 UTC](https://discourse.nodered.org/t/opc-ua-i-cant-read-variable-assigned/29926/1 "2020-07-11T23:31:50Z")
\_I am doing an opc ua communication test for node red and matlab, I can read the assigned data with the predefined nodes of opc\_ua, but I cannot read them when I put the inject node.
Can you help me please.
```auto
[{"id":"689d24fd.a319bc","type":"tab","label":"Flow 6","disabled":false,"info":""},{"id":"1750e074.13e97","type":"OPCUA-IIoT-Write","z":"689d24fd.a319bc","connector":"7e018017.ac62a","name":"","justValue":false,"showStatusActivities":false,"showErrors":true,"x":570,"y":240,"wires":[["e6e683d8.7d539","f4d1c180.82ef4"]]},{"id":"43a6ba79.92db64","type":"debug","z":"689d24fd.a319bc","name":"","active":false,"console":"false","complete":"true","x":890,"y":240,"wires":[]},{"id":"d8d82318.83ced","type":"OPCUA-IIoT-Node","z":"689d24fd.a319bc","injectType":"write","nodeId":"ns=1;s=TestReadWrite","datatype":"Double","value":"","name":"","topic":"","showErrors":true,"x":430,"y":240,"wires":[["1750e074.13e97"]]},{"id":"d20cb893.12cc38","type":"inject","z":"689d24fd.a319bc","name":"","topic":"TestTopicWrite","payload":"1234.56","payloadType":"num","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":260,"y":240,"wires":[["d8d82318.83ced"]]},{"id":"e6e683d8.7d539","type":"OPCUA-IIoT-Response","z":"689d24fd.a319bc","name":"","x":740,"y":240,"wires":[["43a6ba79.92db64"]]},{"id":"f4d1c180.82ef4","type":"OPCUA-IIoT-Server-ASO","z":"689d24fd.a319bc","nodeId":"ns=1;s=TestDouble","browsename":"TestDouble","displayname":"Test Double","objecttype":"BaseDataVariableType","datatype":"Double","value":"","referenceNodeId":"ns=1;s=TestVariables","referencetype":"Organizes","name":"Double","x":720,"y":460,"wires":[["a0109164.afa3a"]]},{"id":"a0109164.afa3a","type":"function","z":"689d24fd.a319bc","name":"thru","func":"\nreturn msg;","outputs":1,"noerr":0,"x":990,"y":460,"wires":[["caac393d.0fdae8"]]},{"id":"caac393d.0fdae8","type":"OPCUA-IIoT-Server","z":"689d24fd.a319bc","port":"55388","endpoint":"UA/NodeRedIIoT","acceptExternalCommands":true,"maxAllowedSessionNumber":"","maxConnectionsPerEndpoint":"","maxAllowedSubscriptionNumber":"","alternateHostname":"","name":"","showStatusActivities":false,"showErrors":false,"asoDemo":false,"allowAnonymous":true,"individualCerts":false,"isAuditing":false,"serverDiscovery":true,"users":[],"xmlsets":[],"publicCertificateFile":"","privateCertificateFile":"","registerServerMethod":"1","discoveryServerEndpointUrl":"opc.tcp://localhost:55388","capabilitiesForMDNS":"","maxNodesPerRead":"","maxNodesPerBrowse":"","delayToClose":"","x":930,"y":340,"wires":[["28168e86.2c10d2"]]},{"id":"28168e86.2c10d2","type":"debug","z":"689d24fd.a319bc","name":"","active":false,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","x":1110,"y":340,"wires":[]}]
```
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [9 September 2020 23:32 UTC](https://discourse.nodered.org/t/opc-ua-i-cant-read-variable-assigned/29926/2 "2020-09-09T23:32:03Z")
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