# Wireless connection for Profinet IO communication

 

- **Language:** EN
- **Published on:** 2016-05-13

## **The case**

- Self-propelled trolley on rails controlled by a Siemens ET200S PLC with an Ethernet port and Profinet IO Device protocol on board.
- The trolley must shuttle between two warehouses, each of which has a Siemens S7-300 PLC with an Ethernet port and Profinet IO Controller protocol, installed in a ground-level electrical cabinet. The ground-level PLCs control the opening/closing of the roller shutters for access to the warehouses.
- Need to make the two ground-level PLCs communicate with the one on the shuttle to exchange information regarding trolley speed, commands, and alarms.
- Since the trolley is self-propelled and in a passage area, it is not possible to connect the network of the two PLCs via cable.

## **Floor plan**

![Image](https://shop2.marcomweb.it/storage/blocks/images/Zekxz60hNoOG1CoMHR2JQJy8yji9DfhI8zIywrt8.webp)

## **Solution**

To allow simultaneous communication between the two ground-level PLCs and the one on the trolley, 3 Mikrotik radios, model **[GrooveA-52HPn](it/shop-online/telecontrollo/radio-wifi/mikrotik-groovea-52hpn-dettagli.html)**, were used.
One radio was installed on the trolley, configured as an AccessPoint, set to use the 5GHz frequency (less external interference), with a high-gain omnidirectional antenna. The radio is powered by the same source that powers the PLC on board the trolley, through the POE injector included in the package.
On the ground, the same GrooveA-52HPn radios were used, configured as Stations and connected to the AccessPoint on the trolley. The power source for these radios is the same that powers the PLCs, again through the POE injector.

The ground-level radios connect to the central radio at startup and create a transparent L2 channel, independent of the IP addresses assigned to the radios themselves (which can also be on a different address class). The communication channel uses the Mikrotik NV2 protocol to achieve high throughput performance and fast channel establishment in case of a radio restart or communication loss.

The radios accept a supply voltage in the range of 9 to 30 VDC, with a maximum absorption of 4.56W @ 24VDC. These are therefore suitable for various situations: for example, it is possible to draw power from a 12VDC battery recharged by a solar panel.

The range of the radios is up to 1 km, thanks to the high-gain omnidirectional antenna with which they are supplied and the maximum output power of 500mW.

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Source: https://shop2.marcomweb.it/en/news/wireless-connection-for-profinet-io-communication

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