cancel
Showing results for 
Search instead for 
Did you mean: 

Modbus TCP App Server not working

Modbus TCP App Server not working

Open
Occasional Contributor

Hi Community,

I am new in using Modbus TCP Server App.

I have setup a simple boolean variable in ctrlX PLC datalayer

Open_0-1725859438544.png

Modbus TCP Server:

Open_1-1725859520180.png

Modbus TCP Client: 

Open_2-1725859641980.png

However the value doesnt update the variable in plc is true in the client variable remain false, tried writing true doesnt work too. 

I tried using 2 ctrlX, 1 as modbus tcp client and another as modbus tcp server same issue.

Anyone had this issues? 

4 REPLIES 4

AndreasL
New Contributor

Does it make a difference if you change the PLC data type to a uint (the modbus registers are 16bit)? 

 

Open
Occasional Contributor

Hi @AndreasL ,

Reading works now after changing the variable to uint. Now i want to write the variable it doesnt work.

PLC:

Open_0-1725862704220.png

Modbus TCP Server:

Open_1-1725862810655.png

Modbus TCP Client:

Open_2-1725862865085.png

AndreasL
New Contributor

Can you write the variable from the datalayer? (So the symbol is readwrite)

Can you test with this master/client? 

https://github.com/ClassicDIY/ModbusTool

Open
Occasional Contributor

Hi @AndreasL 

Yes i am able to write the variable from the datalayer:

Open_0-1725865019274.png

Open_1-1725865045289.png

I tried using the ModbusTool reading worked but writing doesnt work.

Read:

Open_3-1725865163652.png

Write:

Open_4-1725865247810.png

Write succeeded but values in PLC did not change

Open_5-1725865287191.png

Open_6-1725865322116.png

ctrlX Apps:

Open_7-1725865370286.png

Icon--AD-black-48x48Icon--address-consumer-data-black-48x48Icon--appointment-black-48x48Icon--back-left-black-48x48Icon--calendar-black-48x48Icon--center-alignedIcon--Checkbox-checkIcon--clock-black-48x48Icon--close-black-48x48Icon--compare-black-48x48Icon--confirmation-black-48x48Icon--dealer-details-black-48x48Icon--delete-black-48x48Icon--delivery-black-48x48Icon--down-black-48x48Icon--download-black-48x48Ic-OverlayAlertIcon--externallink-black-48x48Icon-Filledforward-right_adjustedIcon--grid-view-black-48x48IC_gd_Check-Circle170821_Icons_Community170823_Bosch_Icons170823_Bosch_Icons170821_Icons_CommunityIC-logout170821_Icons_Community170825_Bosch_Icons170821_Icons_CommunityIC-shopping-cart2170821_Icons_CommunityIC-upIC_UserIcon--imageIcon--info-i-black-48x48Icon--left-alignedIcon--Less-minimize-black-48x48Icon-FilledIcon--List-Check-grennIcon--List-Check-blackIcon--List-Cross-blackIcon--list-view-mobile-black-48x48Icon--list-view-black-48x48Icon--More-Maximize-black-48x48Icon--my-product-black-48x48Icon--newsletter-black-48x48Icon--payment-black-48x48Icon--print-black-48x48Icon--promotion-black-48x48Icon--registration-black-48x48Icon--Reset-black-48x48Icon--right-alignedshare-circle1Icon--share-black-48x48Icon--shopping-bag-black-48x48Icon-shopping-cartIcon--start-play-black-48x48Icon--store-locator-black-48x48Ic-OverlayAlertIcon--summary-black-48x48tumblrIcon-FilledvineIc-OverlayAlertwhishlist