# PLC Redundancy (Device)

**URL:** <https://forum.inductiveautomation.com/t/plc-redundancy-device/10627>\
**Category:** Ignition\
**Created:** [October 15, 2015, 1:45pm UTC](https://forum.inductiveautomation.com/t/plc-redundancy-device/10627 "2015-10-15T13:45:59Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![dhananjay\_vichare](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dhananjay_vichare/32/74712_2.png) [@dhananjay\_vichare](https://forum.inductiveautomation.com/u/dhananjay_vichare)\
**Post date:** [October 15, 2015, 1:45pm UTC](https://forum.inductiveautomation.com/t/plc-redundancy-device/10627/1 "2015-10-15T13:45:59Z")

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Hi,

I have 2 identical PLCs connected with Ignition Server, via Modbus TCP driver.  
I want to check the PLC Handshake and If there is no Handshake with one PLC then switch the Ignition communication to second PLC and vise versa.

In addition, PLC system having dual Ethernet cards (Two Ethernet ports with different IP addresses), In this case I need to check Handshake with both the ports.

I just read about “system.device.setDeviceHostname”. Could it help me in this application?