# A question about a function in opcua programming

**URL:** <https://forum.inductiveautomation.com/t/a-question-about-a-function-in-opcua-programming/3777>\
**Category:** Module Development\
**Created:** [December 19, 2011, 9:37am UTC](https://forum.inductiveautomation.com/t/a-question-about-a-function-in-opcua-programming/3777 "2011-12-19T09:37:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![wengzijue](https://avatars.discourse-cdn.com/v4/letter/w/ee59a6/32.png) [@wengzijue](https://forum.inductiveautomation.com/u/wengzijue)\
**Post date:** [December 19, 2011, 9:37am UTC](https://forum.inductiveautomation.com/t/a-question-about-a-function-in-opcua-programming/3777/1 "2011-12-19T09:37:01Z")

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the code " public void setAddressMap(String addressMap)" in the example of Ignition-ModuleSDK-7.2.8\example\ModbusDriver-v2.

there is no explanation of this function in javadoc and no other fuctions to call it ,can you give me some help about it ?thank you

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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:** [December 19, 2011, 5:04pm UTC](https://forum.inductiveautomation.com/t/a-question-about-a-function-in-opcua-programming/3777/2 "2011-12-19T17:04:01Z")

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It, along with the other setters, are properties on the driver. They’re called when an instance of the driver is instantiated because they all have a DriverProperty defined, which belong to DriverCategory(s), which belong to the DriverMeta.

It’s specific to the Modbus driver, so there’s nothing in the driver API JavaDocs about it.