Pi as Modbus TCP slave. Errors

2026-04-29T07:36:03.353000Z

Hi,
I have similar issue. Is that possible to use more than 4096 registers with Modbus RTU slave?

Pi as Modbus TCP slave. Errors

2020-02-27T16:31:27.800000Z

More errors cannot add any new IW or QW.. Is it the device description that needs to be edited so i can use more IW and QW and if so how to?

Copied the device description file and added under this section <ts:section name="memory-layout"> the following lines
<ts:setting access="visible" type="integer" name="input-size">
<ts:value>8192</ts:value>
</ts:setting>
<ts:setting access="visible" type="integer" name="output-size">
<ts:value>8192</ts:value>
</ts:setting></ts:section>

Now it seems to work as expected. Am I doing something wrong? Is this setting available from the development tool or is the only option to change this in the device description file?

Pi as Modbus TCP slave. Errors

2020-02-27T16:31:25.366000Z

Hi.

When reading the online help it states that the max number of words as a modbus slave is 4096.
First of all why limit at 4096? I want to be able to adress more than so as the Modbus standard permits that.

Second in my Raspberry i get an error if i try to use more than 2047 words.
C0111 Adress out of range.

If I use 2048 words i dont get an error but it doesnt work, The slave icon is read.
If I try to use more than 2048 i get the error C0111
If I try to use 2047 or less then it works.

Is this a bug? Using latest Codesys both runtime and development.

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