# Modbus function code 22

**URL:** <https://forum.inductiveautomation.com/t/modbus-function-code-22/8273>\
**Category:** Ignition\
**Created:** [April 7, 2014, 11:02pm UTC](https://forum.inductiveautomation.com/t/modbus-function-code-22/8273 "2014-04-07T23:02:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Henry](https://avatars.discourse-cdn.com/v4/letter/h/df705f/32.png) [@Henry](https://forum.inductiveautomation.com/u/Henry)\
**Post date:** [April 7, 2014, 11:02pm UTC](https://forum.inductiveautomation.com/t/modbus-function-code-22/8273/1 "2014-04-07T23:02:07Z")

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Is it possible to do a Modbus function code 22 to write to a bit of a word but also use the Device\Address table?

The latest Do-More PLC now has the ability to do a Modbus Function Code 22, but I’m reading the registers through an Ecom 100 card so I would like to use the prefix table to make the addressing easier to do.

Thanks

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**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:** [April 7, 2014, 11:08pm UTC](https://forum.inductiveautomation.com/t/modbus-function-code-22/8273/2 "2014-04-07T23:08:46Z")

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No, any time you need to read or write a bit you’ll have to manually create the SQLTag for it.

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**Author:** ![Henry](https://avatars.discourse-cdn.com/v4/letter/h/df705f/32.png) [@Henry](https://forum.inductiveautomation.com/u/Henry)\
**Post date:** [April 14, 2014, 11:26pm UTC](https://forum.inductiveautomation.com/t/modbus-function-code-22/8273/3 "2014-04-14T23:26:05Z")

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Even when I do native Modbus addressing I still use the prefix to tell me the data type. Could this be added in the future or is it much work ?

Thanks