# Connect to 3458A DMM

**URL:** <https://forum.opentap.io/t/connect-to-3458a-dmm/1373>\
**Category:** Technical\
**Created:** [February 23, 2024, 2:53am UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373 "2024-02-23T02:53:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![shwethakh](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@shwethakh](https://forum.opentap.io/u/shwethakh)\
**Post date:** [February 23, 2024, 2:53am UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373/1 "2024-02-23T02:53:07Z")

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The DMM plugin available in the OpenTAP package repository does not include instrument 3458A. Is there any other package available to connect to this instrument?

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**Author:** ![rolf\_madsen](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@rolf\_madsen](https://forum.opentap.io/u/rolf_madsen)\
**Post date:** [February 23, 2024, 1:26pm UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373/2 "2024-02-23T13:26:30Z")

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Hi @shwethakh and welcome to the forum!

As far as I know there is no plugin for the 3458A.

If you just want to execute some SCPI command you can still set it up as a generic SCPI instrument and connect to it and send commands to it that way.

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**Author:** ![shwethakh](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@shwethakh](https://forum.opentap.io/u/shwethakh)\
**Post date:** [February 26, 2024, 12:35am UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373/3 "2024-02-26T00:35:07Z")

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Hi @rolf_madsen , thanks for the response. Yeah we did try connecting to it as a generic SCPI instrument but the Open() method is giving a timeout error while executing the \*IDN? query. Please find the log attached.

 ![NonScpInstrument](https://us1.discourse-cdn.com/flex020/uploads/opentap/original/2X/1/12a619faf6dd31126ee8c38d68eaee6f454be423.jpeg)

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**Author:** ![rolf\_madsen](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@rolf\_madsen](https://forum.opentap.io/u/rolf_madsen)\
**Post date:** [February 26, 2024, 9:30am UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373/4 "2024-02-26T09:30:24Z")

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@shwethakh, It sounds like this instrument does not support the \*IDN? command mandated in IEEE488.2.

There is no way around this without doing a bit of programming as there is currently no existing plugin for this specific instrument. You can make a subclass of ScpiInstrument which overrides the QueryIdn property. Something like this:

```cs
public class CustomScpiInstrument : ScpiInstrument {
    // On 3458A ID? can be used instead of *IDN?
    protected override string QueryIdn() => ScpiQuery("ID?");
}

```

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**Author:** ![shwethakh](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@shwethakh](https://forum.opentap.io/u/shwethakh)\
**Post date:** [February 27, 2024, 5:19am UTC](https://forum.opentap.io/t/connect-to-3458a-dmm/1373/5 "2024-02-27T05:19:34Z")

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@rolf_madsen, thanks for this! Will try it and get back if we need any additional help.