Powering Unipi PLCs through PoE

This tutorial describes the connection of Unipi controllers using 802.3at PoE+ splitter. This connection is useful especially if you need to place the PLC in locations lacking a conventional ~230V socket (ie. sensor stations). This tutorial will show you how to power the Unipi over Ethernet cable while retaining local network connectivity.

• Cat6 network cable (RJ45)
• conductor (Cu, 0.5mm2)
• Planet IPOE-162S PoE splitter
• Planet GSD-908HP network switch
  • The switch used is just one of possible variants. You can use any 802.3at PoE+ compliant network switch.
• Unipi Axon PLC

1. set the splitter for 24V voltage using the onboard switch
2. connect the splitter’s V+ clamp to the PLC’s 24V clamp
3. connect the splitter’s V- clamp to the PLC’s GND clamp
4. using the network cable, connect the splitter’s Data Out port with the PLC’s ETH port
5. plug an 802.3at PoE+ compatible network cable into the splitter‘s PoE In port

1. use one of the switch ports to connect it with the PoE In port on the splitter via a suitable network cable
2. repeat the step for any other additional splitter
3. connect the WAN network cable into the port 9

Using a single splitter to power multiple PLCs is not recommended!

The calculations below are applicable for GSD-908HP PoE+ switch and IPOE-162S PoE+ splitter.

1. maximum load of the Neuron L403 = 25W
2. maximum load of the splitter = 25W
   • 25W – 24W = 1W
   • the resulting value is a positive number = suitable
3. maximum load of the switch = 100W
   • 100W ⁄ 24W = 4,166

Based on these calculations, we can safely use 4 PoE+ powered Neuron L403's

1. maximum load of the Axon S105 = 25W
2. maximum load of the splitter = 25W
   • 25W – 12W = 13W
   • the resulting value is a positive number = suitable
3. maximum load of the switch = 100W
   • 100W ⁄ 12W = 8,333

Based on these calculations, we can safely use 8 PoE+ powered Axon S105's

1. maximum power input:
   • Axon L205 → 19,5W (1x)
   • Axon M205 → 16W (2x)
   • Axon S105 → 12W (remaining)
2. maximum load of the splitter = 25W
   • 25W – 12W = 13W
   • 25W – 16W = 9W
   • 25W – 19.5W = 5.5W
   • the resulting value is a positive number = suitable
3. maximum load of the switch = 100W
   • 100W – 19,5W – 2x16W = 48.5W
   • The remaining: 48.5W ⁄ 12W = 4.041

Based on these calculations, a single switch can power 1× Axon L205, 2× Axon M205 and 4× Axon S105