# Hardware options

**URL:** <https://forum.inductiveautomation.com/t/hardware-options/12090>\
**Category:** Ignition\
**Created:** [August 31, 2016, 12:48pm UTC](https://forum.inductiveautomation.com/t/hardware-options/12090 "2016-08-31T12:48:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AJBerera](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@AJBerera](https://forum.inductiveautomation.com/u/AJBerera)\
**Post date:** [August 31, 2016, 12:48pm UTC](https://forum.inductiveautomation.com/t/hardware-options/12090/1 "2016-08-31T12:48:06Z")

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Hello all,  
I am looking for a way to evaluate relay logic using Ignition on machines without PLCs. I was hoping you all have had some experience doing this for smaller systems. I would like a simple ethernet solution to read and write relay states and I have 24vdc and 120vac signals to deal with.  
Thanks for your insights!

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**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:** [August 31, 2016, 1:44pm UTC](https://forum.inductiveautomation.com/t/hardware-options/12090/2 "2016-08-31T13:44:53Z")

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The key to this problem is ensuring outputs turn off or otherwise go to some predictable and relatively safe state when communications are broken or delayed. I/O modules generally have some form of timeout, either explicit or part of their comm protocol, that does this. However, typical polling drivers (query - response) won’t write to a device without an explicit new value. So your ladder logic replacement code will have to use system.opc.write\* calls on a repeating schedule to make sure writes are sent within the timeouts for the device you choose.

FWIW, I’m working on a new driver module that implements a variety of Ethernet/IP features, including I/O scanning. This will make it possible to operate Allen-Bradley ethernet FlexIO, PointIO, and even 1756 chassis I/O from Ignition without a PLC. Send your contact info in a private message if you’d like previews as I prepare to roll it out. (Actually, anyone reading who’s interested can do so.)