# Micro 820 to Ignition - What am I doing wrong?

**URL:** <https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746>\
**Category:** Ignition\
**Tags:** ignition79\
**Created:** [January 6, 2022, 8:11pm UTC](https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746 "2022-01-06T20:11:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jparsons](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@jparsons](https://forum.inductiveautomation.com/u/jparsons)\
**Post date:** [January 6, 2022, 8:11pm UTC](https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746/1 "2022-01-06T20:11:49Z")

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I am communicating from a micro 820 to ignition edge through modbus tcp. My coil is working but my holding register values are not connecting. I dont know what I am doing wrong. Does anyone see anything wrong with these values?

Micro 820:  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/7/175cde05c03eb4d38dece407bebfa579293ab8f5.png)

Ignition Modbus Mapping Table:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/c/4c0af1af4117ef201985216890d562850111990b.png)

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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:** [January 6, 2022, 8:16pm UTC](https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746/2 "2022-01-06T20:16:16Z")

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Looks like Modicon addressing, which uses a numeric prefix to indicate the area to read from, and your Modbus Address in both cases should just be 1.

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<div class="post-metadata">

**Author:** ![jparsons](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@jparsons](https://forum.inductiveautomation.com/u/jparsons)\
**Post date:** [January 6, 2022, 8:21pm UTC](https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746/3 "2022-01-06T20:21:47Z")

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Hey Kevin, I do not follow. The Modbus address coming out of the PLC is 40001. If its only a 16bit address then that should also appear in ignition as 40001. Is that not right?

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<div class="post-metadata">

**Author:** ![jparsons](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@jparsons](https://forum.inductiveautomation.com/u/jparsons)\
**Post date:** [January 6, 2022, 8:31pm UTC](https://forum.inductiveautomation.com/t/micro-820-to-ignition-what-am-i-doing-wrong/54746/4 "2022-01-06T20:31:49Z")

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Nevermind, I got it to work. I just changed the 40001 address to HR1