# OPC-UA BadTypeMismatch (0x80740000) - S7\_1500
**URL:** https://discourse.nodered.org/t/opc-ua-badtypemismatch-0x80740000-s7-1500/54935
**Category:** General
**Created:** [9 December 2021 14:17 UTC](https://discourse.nodered.org/t/opc-ua-badtypemismatch-0x80740000-s7-1500/54935 "2021-12-09T14:17:06Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@nico25](https://discourse.nodered.org/u/nico25)
#### Post date: [9 December 2021 14:17 UTC](https://discourse.nodered.org/t/opc-ua-badtypemismatch-0x80740000-s7-1500/54935/1 "2021-12-09T14:17:06Z")
Hello,
i am using node-red-contrib-opcua in my current project.
I am able to read/write boolean values with the opc-client to my S7-1500.
Now i am trying so send a numerical value e.g 70009, to my S7.
For some reason i always get the error BadTypeMismatch (0x80740000)when trying to do so.
This is what my topic looks like:
ns=3;s="RW\_RFID\_MASTER"."THIS"[0]."Wr\_UserData0";datatype=number
The datatype of Wr\_UserData0 is LINT.
What am I doing wrong?
Also: I am not a Pro, so be kind 😃
Edit:
Was able to solve it. Leaving this here, for the people googling this issue:
While reading using the client node, it is good enough to define the datatype as number,string, boolean in Nodered. While writing, you have to define the OPC-UA datatype in the topic.
You can find an overview here:
[https://www.mathworks.com/help/opc/ug/opc-ua-server-data-types.html](https://www.mathworks.com/help/opc/ug/opc-ua-server-data-types.html)
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [7 February 2022 14:17 UTC](https://discourse.nodered.org/t/opc-ua-badtypemismatch-0x80740000-s7-1500/54935/2 "2022-02-07T14:17:52Z")
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