# Modbus Driver Behavior **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [February 13, 2023, 9:57pm UTC](https://forum.inductiveautomation.com/t/modbus-driver-behavior/69796 "2023-02-13T21:57:01Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![kevin.deyoung](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.deyoung/32/9558_2.png) [@kevin.deyoung](https://forum.inductiveautomation.com/u/kevin.deyoung)\ **Post date:** [February 13, 2023, 9:57pm UTC](https://forum.inductiveautomation.com/t/modbus-driver-behavior/69796/1 "2023-02-13T21:57:01Z")
I'm using the Ignition Modbus driver for the first time, but it is not my first exposure to Modbus/TCP by a long shot. The customer environment I'm currently working in has a couple of controllers (unit 1 and unit 2) on the other side of a Modbus Gateway. It is their practice to either take a controller offline, or power it down, when the equipment it is controlling is not in use. The problem seems to be that if a particular piece of equipment is down, and happens to be the first one in the driver scan list, it will never attempt a read from the second controller. It makes attempts communicating with the controller that is out of service and disconnects after the configured number of attempts. It never attempts to issue commands to the other controller that is online. Is it possible to configure two different device connections to the same Modbus Gateway using one for Unit 1 and the other for Unit 2? ---
**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:** [February 13, 2023, 11:24pm UTC](https://forum.inductiveautomation.com/t/modbus-driver-behavior/69796/2 "2023-02-13T23:24:46Z")
Yes, you can and should do that. ---
**Author:** ![nideyijuyidong](https://avatars.discourse-cdn.com/v4/letter/n/7cd45c/32.png) [@nideyijuyidong](https://forum.inductiveautomation.com/u/nideyijuyidong)\ **Post date:** [February 14, 2023, 8:47am UTC](https://forum.inductiveautomation.com/t/modbus-driver-behavior/69796/3 "2023-02-14T08:47:28Z")
I have the same problem, I use a periodic script, which queries each device if it can communicate, and if the communication fails, I disable all variables for this unit ID (actually a UDT). And then it can read other devices. ---
**Author:** ![kevin.deyoung](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.deyoung/32/9558_2.png) [@kevin.deyoung](https://forum.inductiveautomation.com/u/kevin.deyoung)\ **Post date:** [February 14, 2023, 9:05pm UTC](https://forum.inductiveautomation.com/t/modbus-driver-behavior/69796/4 "2023-02-14T21:05:07Z")
Thank you for the response Phil. I've made the change and it looks like that will do the trick. Thanks again.