Hi guys, I forget to feedback on your support, the solution you give to me worked like a charm!

Thank you very much!

Hi guys, thanks for your replies. Let me provide you more details.

1.- I am trying to control this device:

This device is an ATS controller that helps with load sharing and a lot of stuff. This device talks Modbus TCP/IP and have a very large list of Modbus registers, like the one with the offset 4104, that is indicated as "System Control Key" and its complement in the offset 4015 indicated as "System Control Key Compliment", both defined as Write-only registers (Number 8 and 9 in the list).

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2.- I have to set these two registers using the following table to trigger functions in the device.

3.- The instructions of the device says this about the control:

" ***Control is performed by sending System Control Keys to the module, and also sending the bitwise opposite (or one’s complement) of the control key to another register ‘in the same write operation’ for security.

To Modbus register 4104 (decimal) write the system control key as below
To Modbus register 4105 (decimal) write the compliment of the system control key as below

Both of these registers MUST be written to the controller at the SAME TIME using the SAME MODBUS WRITE
COMMAND.

A table of Control Keys and the one's complement of the keys is included overleaf.*** "
"

4.- But I figured a solution to test it with the Modbus "Write data" feature in the legacy data sources page at my Mango. (I construct the decimal value that results from joining together the key and its compliment). And IT WORKS! Yesterday I was able to trigger functions using this:

5.- Then I proceeded to create a data point inside my Modbus IP data source that triggers this 4104 offset register and a Write-only type, as the following pic:

6.- My intention is to set this data point from a view that I designed by clicking the button in the SVG. But it doesn't work... I try to use something like:

<div ma-selector="#ats_x5F_btn_x5F_manual" ng-click="$ctrl.controllerClick($ctrl.data.atsSistemControlKey, 2339796105)"></div>

with the method

this.controllerClick = (variable, value) => {
        variable.value = value;
    };

I tried to use a virtual data point and this method set the value successfully. But it doesn't work with the Modbus Write-only data point.

7.- I did test the Phil suggestion, to set the data point from the data point details page, but it doesn't work either, so I think that there is a special way to set Write-only data points or something else.

8.- I also tried to use a virtual data point that set the Modbus data point with a scripting data source, but it says to me this error:

"Permissions failure setting point DP_238a7211-42a8-469c-8b53-444fdc6fd9c2", this XID is the Modbus IP system control key data point.

9.- When I try to set the data point as settable, it triggers an error saying "Unreliable data point" or something like this, forgive me, tomorrow I can test with the equipment and send you the exact error logs so you can help me.

Sorry for this very large message, but I think is necessary to set the context.

Hi guys, I am wondering if you can help me with a little issue with a Write-only Data point inside a Modbus IP Datasource. I am trying to set the value of this data point through a scripting data source, but it doesn't work.

Through the legacy data sources page of my mango, I had tested successfully with the write data command, but when I create a data point with the type "Write-only" and try to set a value to it, it doesn't work, so I don't know how I can set Write-only data points to write on my device registers.

Let me know if I make myself clear and if you can help me with this or give me some ideas. Thanks!