# Using Modbus Slaver software to test that communication is normal and why data cannot be displayed properly **URL:** \ **Category:** Ignition\ **Tags:** ignition78\ **Created:** [December 19, 2018, 1:36pm UTC](https://forum.inductiveautomation.com/t/using-modbus-slaver-software-to-test-that-communication-is-normal-and-why-data-cannot-be-displayed-properly/21493 "2018-12-19T13:36:32Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![tao.xu](https://avatars.discourse-cdn.com/v4/letter/t/51bf81/32.png) [@tao.xu](https://forum.inductiveautomation.com/u/tao.xu)\ **Post date:** [December 19, 2018, 1:36pm UTC](https://forum.inductiveautomation.com/t/using-modbus-slaver-software-to-test-that-communication-is-normal-and-why-data-cannot-be-displayed-properly/21493/1 "2018-12-19T13:36:32Z")
step1: ![](https://us1.discourse-cdn.com/inductiveautomation/original/2X/a/af5896f27c7921411e776f56f3922ff3c5eb5d9a.png) step2: ![](https://us1.discourse-cdn.com/inductiveautomation/original/2X/b/b471768652d65229cf6f9ffb6d596431d8fe4f0a.png) step3: ![](https://us1.discourse-cdn.com/inductiveautomation/original/2X/f/f5b2c74d9761b54e326030c217d10d2f44f16812.png) step4: ![](https://us1.discourse-cdn.com/inductiveautomation/original/2X/3/330af4f3dcbde8270d2aa7ffbfaa180855f99b21.png) ---
**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:** [December 19, 2018, 1:37pm UTC](https://forum.inductiveautomation.com/t/using-modbus-slaver-software-to-test-that-communication-is-normal-and-why-data-cannot-be-displayed-properly/21493/2 "2018-12-19T13:37:26Z")
You need to set the “One-based Addressing” setting to false for that device connection. It also helps to start without the mapping. Just make an OPC tag in the designer with “[device]255.C0” or “[device]255.C1” as the OPC Item Path.