# Quality bad ignition to Modbus rtu **URL:** \ **Category:** Maker\ **Tags:** ignition81\ **Created:** [May 21, 2023, 12:20pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992 "2023-05-21T12:20:18Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 21, 2023, 12:20pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/1 "2023-05-21T12:20:18Z")
Hello Team, May you lead me, I have tried to connect Delta plc dvp20sx211 using USB to ignition 8.1.27 but I always read quality bad time out. I checked with KEPserverEx and receive data but not with ignition I noticed that the time stamp is incorrect also 1/1/1601 Regards, ---
**Author:** ![Faisal\_Shaikh](https://avatars.discourse-cdn.com/v4/letter/f/3ec8ea/32.png) [@Faisal\_Shaikh](https://forum.inductiveautomation.com/u/Faisal_Shaikh)\ **Post date:** [May 24, 2023, 10:20am UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/2 "2023-05-24T10:20:27Z")
Hi, Could you share the configuration for the communication ---
**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:** [May 24, 2023, 11:57am UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/3 "2023-05-24T11:57:17Z")
Does the USB interface show in the PC as a serial port? If not, Ignition won't support it. If it does, then you need to follow the instructions for Modbus RTU in IA's driver. ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 5:16pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/4 "2023-05-26T17:16:15Z")
Yes, the USB is recognised as serial port, I followed and double check what is written in the document but always failed ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 5:25pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/5 "2023-05-26T17:25:33Z")
Regarding delta plc dvp20sx211: . one USB port is for communicating with Isopsoft (delta plc IDE) ASCII, 9600,7,E,1 RS232 . One RS485 port, 9600,RTU, 8,N,1, I tried to connect it with KEPserverEx and works but have to specify ID address = 1 But with Ignition scada: COM4, 9600,RTU, 8,N,1 always bad quality ---
**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:** [May 26, 2023, 5:35pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/6 "2023-05-26T17:35:49Z")
Specifying address == 1 is normal for Modbus RTU. Normal settings for Modbus RTU are 8-E-1 (per the Modbus specification). If using no parity, you **must** use two stop bits. Ignition's driver defaults to address zero if not included in the OPC Item. So you must always include the `1.` prefix yourself. Also, Ignition does not support ASCII mode at all. ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 5:47pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/7 "2023-05-26T17:47:28Z")
Good to know about parity, I am going to test it now. Thanks. Where to add the prefix 1. about the address. ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 6:09pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/8 "2023-05-26T18:09:53Z")
![IMG_20230526_205412](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/e/4e084f410e3c44ea7bab2b3c9575a49df19c34dc.jpeg) ![IMG_20230526_210127](https://us1.discourse-cdn.com/inductiveautomation/original/3X/7/4/7483cd1ac79b6693c4fdae0f8862ad6885d57bd6.jpeg) ![IMG_20230526_210216](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/e/8ef10fe8bc20bc55d1a3d84bb2dc1bc2bba0d054.jpeg) ![IMG_20230526_210258](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/7/67247883aa2335ecfb6789ce4de17b2ac2a48ba0.jpeg) ![IMG_20230526_210838](https://us1.discourse-cdn.com/inductiveautomation/original/3X/b/2/b2c57244a140a7981b992d5ac64df8b361cc2376.jpeg) ---
**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:** [May 26, 2023, 6:42pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/9 "2023-05-26T18:42:21Z")
You have "Unit ID" set to zero in your address mapping. You said Kepware worked with unit ID 1. (Consider not using mappings--they are only needed for browsing.) ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 6:58pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/10 "2023-05-26T18:58:30Z")
IT WORKS, I have been dealing with it since two weeks, as a conclusion: . Ignition can communicate with delta PLC through RS485/RS232 over USB (I use standard converter) . Protocol config: RTU, 9600, E,1, . Specify Unit ID inside address == 1 I like ignition support and philosophy. Thank you ---
**Author:** ![Johnny\_Andimaharo](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@Johnny\_Andimaharo](https://forum.inductiveautomation.com/u/Johnny_Andimaharo)\ **Post date:** [May 26, 2023, 6:59pm UTC](https://forum.inductiveautomation.com/t/quality-bad-ignition-to-modbus-rtu/73992/11 "2023-05-26T18:59:41Z")
![IMG_20230526_214849](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/8/68bd1f96ce7aed477403989916cbeb064612387c.jpeg) 😀