# RS-485 Analog I/O Digital I/O works properly coupled to resistors, however when sensors 4-20mA are coupled didn’t work

**URL:** <https://forums.digi.com/t/rs-485-analog-i-o-digital-i-o-works-properly-coupled-to-resistors-however-when-sensors-4-20ma-are-coupled-didn-t-work/13702>\
**Category:** Interface/Development Boards\
**Tags:** adapter, 4-20ma, xbee\
**Created:** [October 7, 2014, 9:24am UTC](https://forums.digi.com/t/rs-485-analog-i-o-digital-i-o-works-properly-coupled-to-resistors-however-when-sensors-4-20ma-are-coupled-didn-t-work/13702 "2014-10-07T09:24:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![srlager](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@srlager](https://forums.digi.com/u/srlager)\
**Post date:** [October 7, 2014, 9:24am UTC](https://forums.digi.com/t/rs-485-analog-i-o-digital-i-o-works-properly-coupled-to-resistors-however-when-sensors-4-20ma-are-coupled-didn-t-work/13702/1 "2014-10-07T09:24:00Z")

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Please,  
See test result at link:  
[http://www.dec.uem.br/mbr/arq/test\_A\_I\_adpater.docx](http://www.dec.uem.br/mbr/arq/test_A_I_adpater.docx)

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**Author:** ![mvut](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.digi.com/mvut/32/31_2.png) [@mvut](https://forums.digi.com/u/mvut)\
**Post date:** [October 9, 2014, 11:31am UTC](https://forums.digi.com/t/rs-485-analog-i-o-digital-i-o-works-properly-coupled-to-resistors-however-when-sensors-4-20ma-are-coupled-didn-t-work/13702/2 "2014-10-09T11:31:03Z")

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A Digital IO adapter does not accept 4 - 20mA Analog signals. You need to use the Analog Adapter for that.

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<div class="post-metadata">

**Author:** ![srlager](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@srlager](https://forums.digi.com/u/srlager)\
**Post date:** [October 13, 2014, 10:33am UTC](https://forums.digi.com/t/rs-485-analog-i-o-digital-i-o-works-properly-coupled-to-resistors-however-when-sensors-4-20ma-are-coupled-didn-t-work/13702/3 "2014-10-13T10:33:05Z")

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Hi Mvut,  
I must have spelled it wrong because we’re using the analog adpatador (XA-Z14-CS5PH-A XBee Analog IO adapter external RPSMA). As the description of this equipment on link ([http://www.digi.com/products/wireless-modems-peripherals/wireless-range-extenders-peripherals/xbee-zb-adapters#models](http://www.digi.com/products/wireless-modems-peripherals/wireless-range-extenders-peripherals/xbee-zb-adapters#models))  
it could do the conversion but it can not.