Infrastructure​

Hi there!

I'm working on a PC application, implementing the OpenGear Protocol. The intention is to facilitate an automated testing environment for OpenGear devices, independently from the DashBoard application which, in my opinion, is intended more for interactive control. I use the "openGear Development Guide Part II – Communications and Control" as a reference for my work.

In general, the query of device parameters worked really well until I stated to implement a reader for message OGP_GET_ARRAY_ELEMENT. Whenever I send that message to the network controller MFC-OG3-M, I receive a reply containing the error code OGP_INVALID_LENGTH.

One example:

Tx: [ba d2 ac e5 00 10 4c 00 04 00 08 30 00] // OGP_GET_ARRAY_ELEMENT request from CTRL to SLOT 0, OID 0x0830, array index 0

Rx: [ba d2 ac e5 10 00 cc 00 04 02 08 30 00] // OGP_GET_ARRAY_ELEMENT response from SLOT 0 to CTRL with error code 0x02, OGP_INVALID_LENGTH

Is there anything wrong in my request, or what else cound be the reason of that error?

The development guide doesn't state OGP_INVALID_LENGTH as a possible error of OGP_GET_ARRAY_ELEMENT.

Note: I'm using the quite old revision 03 (April 2008) of the documentation. Maybe there are later revisions with udateed information. How can I get an update of this document?

#openGear

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Joerg Vogler
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Thanks for the support I received by mail.

The OGP_GET_ARRAY_ELEMENT request shall look like this: [ba d2 ac e5 00 10 4c 00 05 00 08 30 00 00]

• Content length = 5
• Two bytes for the index of the requested array element.

My old copy of the protocol documentation was outdated in that regard.

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Joerg Vogler
QA Engineer
LYNX Technik AG
Weiterstadt Germany
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Original Message:
Sent: 04-16-2026 03:53
From: Joerg Vogler
Subject: OpenGear Protocol - Error in OGP_GET_ARRAY_ELEMENT

Hi there!

I'm working on a PC application, implementing the OpenGear Protocol. The intention is to facilitate an automated testing environment for OpenGear devices, independently from the DashBoard application which, in my opinion, is intended more for interactive control. I use the "openGear Development Guide Part II – Communications and Control" as a reference for my work.

In general, the query of device parameters worked really well until I stated to implement a reader for message OGP_GET_ARRAY_ELEMENT. Whenever I send that message to the network controller MFC-OG3-M, I receive a reply containing the error code OGP_INVALID_LENGTH.

One example:

Tx: [ba d2 ac e5 00 10 4c 00 04 00 08 30 00] // OGP_GET_ARRAY_ELEMENT request from CTRL to SLOT 0, OID 0x0830, array index 0

Rx: [ba d2 ac e5 10 00 cc 00 04 02 08 30 00] // OGP_GET_ARRAY_ELEMENT response from SLOT 0 to CTRL with error code 0x02, OGP_INVALID_LENGTH

Is there anything wrong in my request, or what else cound be the reason of that error?

The development guide doesn't state OGP_INVALID_LENGTH as a possible error of OGP_GET_ARRAY_ELEMENT.

Note: I'm using the quite old revision 03 (April 2008) of the documentation. Maybe there are later revisions with udateed information. How can I get an update of this document?

#openGear

------------------------------
Joerg Vogler
------------------------------