# MODBUS RTU value fail **URL:** \ **Category:** Ignition\ **Created:** [November 13, 2022, 1:58am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-value-fail/66427 "2022-11-13T01:58:23Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![rob.iso\_86](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@rob.iso\_86](https://forum.inductiveautomation.com/u/rob.iso_86)\ **Post date:** [November 13, 2022, 1:58am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-value-fail/66427/1 "2022-11-13T01:58:23Z")
![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/d/9d1a0f4ae7c31832e90a18c8ac05b8c38631d28f.png) Hi all, i'm trying to generate a variable from CONTROLLINO (Arduino mega based) modbus register. In my case is a Coil (%QX0.1), the name of the connection is TEST. The connection is right (connected), but the value is "bad" like the "Quality". The type is set on boolean. What could be the problem? ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [November 13, 2022, 2:23am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-value-fail/66427/2 "2022-11-13T02:23:45Z")
What’s going on in the gateway logs? Without additional information I’d guess that you either never got “connected” (successfully opened the serial port) or that the device isn’t responding and you’re constantly “reconnecting” after 3 consecutive timeouts occur. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [November 13, 2022, 2:54am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-value-fail/66427/3 "2022-11-13T02:54:51Z")
For real serial connections, you will need the slave unit #. Try `[TEST]1.C1`.