# Walchem Modbus confusion **URL:** \ **Category:** General Discussion\ **Created:** [February 10, 2014, 9:16pm UTC](https://forum.inductiveautomation.com/t/walchem-modbus-confusion/7984 "2014-02-10T21:16:38Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![whalensl](https://avatars.discourse-cdn.com/v4/letter/w/e5b9ba/32.png) [@whalensl](https://forum.inductiveautomation.com/u/whalensl)\ **Post date:** [February 10, 2014, 9:16pm UTC](https://forum.inductiveautomation.com/t/walchem-modbus-confusion/7984/1 "2014-02-10T21:16:38Z")
I am connected to a Walchem Webmaster unit. The unit is used to control water treatment plants in small applications. Anyway, there are three configurable analog inputs that include alarm setpoints. I am trying to pull the data from the analog inputs and have set up “data types”, since the addressing is much simpler this way then through the modus addressing module. I have a bit for high and high-high alarms, and the high and high-high alarm set points. I have input name, scaled input, status, and units as well. The later parameters work. The set point values are bizzare. When I set up the SQL Tags - Data Type Instance for the first analog, all works well. As soon as I add the next analog channel, everything is fine, with the exception of the setpoint values. They either go to zero, or some other arbitrary value. I have tried everything to correct this. The manufacturers literature indicates that the values are floating inverse. I have tried using FLOAT and INT. I have used HRF, IRI, and combination. Nope. Any ideas would be appreciated. ---
**Author:** ![witman](https://avatars.discourse-cdn.com/v4/letter/w/d2c977/32.png) [@witman](https://forum.inductiveautomation.com/u/witman)\ **Post date:** [February 11, 2014, 4:49pm UTC](https://forum.inductiveautomation.com/t/walchem-modbus-confusion/7984/2 "2014-02-11T16:49:17Z")
I’m not familiar with this particular device, but here’s a couple things I’d check: 1 - Have you tried setting the “Reverse Word Order” option under “Show advanced properties?” on the device? [attachment=0]Modbus TCP Device Settings.jpg[/attachment] 2 - Is it possible something in your UDT is using the wrong number of bits (different number expected in Ignition than actual number of bits in the PLC)? ---
**Author:** ![Pat](https://avatars.discourse-cdn.com/v4/letter/p/8491ac/32.png) [@Pat](https://forum.inductiveautomation.com/u/Pat)\ **Post date:** [February 11, 2014, 5:41pm UTC](https://forum.inductiveautomation.com/t/walchem-modbus-confusion/7984/3 "2014-02-11T17:41:25Z")
You might also take a look at disabling the Allow Read/Write Multiple settings. I was communicating with a HACH unit and reading one data value was fine, when I added other values they went wacky. I ended up having to disable the Allow Read Multiple Registers Request.