IO-Link is the open standard for the last few metres between sensor and controller. It is laid down in IEC 61131-9 and is vendor-independent. It needs no fieldbus wiring of its own: the device connects to an IO-Link master over an ordinary unscreened three-wire cable, and the master passes the values on to the plant fieldbus — PROFINET, EtherNet/IP, EtherCAT or Modbus.
Why this matters in measurement
An analogue signal loses accuracy on its way to the controller — through cable length, contact resistance and interference. IO-Link transmits the reading digitally: what the sensor measured is what arrives. Parameters and diagnostics run over the same cable. A device can therefore be scaled, tared and read out while running, and when a device is replaced the master writes its settings back into the new one by itself.
Two routes to IO-Link in weighing
1. IO-Link amplifier — the existing load cell stays
The amplifier sits between the strain gauge load cell and the master. It excites the bridge, converts the mV/V signal and passes it on as IO-Link. This is the route when a cell is already installed or when a particular design is required — the cell may come from any manufacturer.
In a housing: the EMMA IO-Link strain gauge amplifier (EPG-IO), with one input for a full strain gauge bridge, 16 bit resolution and at least IP65 protection.
As an OEM board to build into your own device: single-channel the EOMC (MCUT-E) and the round EOMD (MCUT-R), two-channel the EOME (MEUT-E) and the EOMF (MEUTS-SIL) with Performance Level c.
2. IO-Link inside the sensor — the electronics sit in the cell
Here there is no second device: converter and IO-Link interface are inside the load cell itself. That means fewer parts, no amplifier housing in the cabinet and a single cable from the cell onwards. Currently in the range: the LBOA-IO shear beam load cell with IO-Link.
Which route fits?
If the plant is already built and the load cell is installed, the amplifier is the shorter path — it is added to the existing cell. If you are building new and the design is free to choose, a cell with built-in IO-Link saves one device and one connection point. For an OEM application, where the electronics move into your own enclosure, the OEM boards are the right starting point.
Not sure what fits your application?
Describe the measuring task to us — load, available space, environment and the controller it has to reach. We will tell you which combination will carry it, and if none of the standard devices fits, whether a custom solution is worth it. Price, data sheet and delivery time are online with every article.