How IO-Link Works with Alicat Flow and Pressure Devices

Read flow, pressure, and temperature from one device, over one cable. Our controllers also hold the setpoint on their own. Available for gas, liquid, and pressure.

Ask an Engineer

IO-Link systems and communication

IO-Link devices connected by M12 cables to ports on an IO-Link master, which passes data on to a PLC or computer. Cable runs are up to 20 m.

Devices connect to ports on one master, which passes the data on to your PLC or computer.

IO-Link is the first globally standardized IO communication protocol, written as IEC 61131-9. It runs point-to-point communication between sensors and actuators on a 3-wire sensor cable.

That’s what makes IO-Link devices easy to install. They’re “plug-and-play” within your existing architecture, with no addresses to set. Runs go up to 20 m.

One master then connects your devices to whatever fieldbus you run: PROFINET, EtherNet/IP, EtherCAT, or Modbus TCP.

IO-Link sensors vs IO-Link mass flow controllers

Alicat mass flow controllers and pressure controllers measure and control. Most IO-Link flow devices only measure.

IO-Link flow meters are common. IO-Link flow controllers are not. Alicat offers the first mass flow controller configured with IO-Link. Read more in our IO-Link announcement.

“We didn’t just introduce more sensors. These are multivariate measurement instruments that control flow or pressure of gas or liquids.”

— David Davis, VP of engineering, Alicat Scientific

A meter reports the reading. A controller holds your setpoint.

Using IO-Link devices from Alicat delivers:

Range to match the job. Gas flow from 0.5 SCCM full scale, up to 10,000 SLPM full scale, plus liquid, and pressure from vacuum upward. Turndown ratio can be up to 10,000:1, dependent on the device selected.
Class A or Class B power. Class A runs meters and small-valve controllers. Class B gives larger valves the current they need. Users must calculate the total load for all the sensors attached to a master to know how many devices can be powered by it.
Your gas library comes along. Gas Select and COMPOSER, if included, work over IO-Link, so you can change gas or mix your own.
Accuracy does not change. Moving to IO-Link does not reduce the accuracy of the Alicat device.

What data does an Alicat IO-Link device send?

Every Alicat sends its full set of readings continuously. Depending on how your device is configured, a gas flow meter reports mass flow, volumetric flow, pressure, temperature, barometric pressure, humidity, and a running total. Controllers also report the setpoint they are holding, and the valve drive usage. The device manual lists what each series reports.

Check byte count limitations before making a selection. Each M, MC, and LC sends 32 bytes of data, the most IO-Link allows. Controllers send 4 bytes back for the setpoint. Some masters read only part of that by default, and that is the most common reason a first start-up fails. Your device manual will list which parameters your model reports.

Alicat mass flow and pressure devices with IO-Link

One connection per device, on the master you already run.

Mass Flow Controller MC-Series from Alicat

Laminar differential pressure mass flow controllers
Compatible with 98 gases, 130 gases with corrosion resistant models
0.5 SCCM full scale – 12,000 SLPM full scale options
Live flow, pressure, and temp readings
High accuracy: as good as ± 0.5% of reading or ± 0.1% of full scale, whichever is greater
0.01 – 100% of full scale control
30 ms control response
Class I Div 2, ATEX Zone 2 options

Alicat Scientific Low Pressure Drop Mass Flow Meter

As little as 0.07 PSID pressure drop
Compatible with 98 gases, stainless steel also available
0.5 SCCM – 1,000 SLPM full scale
Live flow, pressure, and temp readings
For pressures 11.5 – 60 PSIA
High accuracy: as good as ± 0.6% of reading or ± 0.1% of full scale, whichever is greater
10,000:1 turndown

Built for water or nine other pure liquids
0.5 CCM – 10 LPM full scale
Volumetric flow accuracy: as good as ± 2% of full scale
−10°C to 60°C

Built for DI water or nine other pure liquids
0.5 CCM – 10 LPM full scale
Volumetric flow accuracy: as good as ± 2% of full scale
−10°C to 60°C
Temperature and pressure also reported
Laminar differential pressure measurement technology

Compatible with a variety of non‑corrosive and corrosive gases
10 TorrA to 3000 PSI full scale
As good as ± 0.125% of full scale accuracy
± 0.08% of full scale repeatability
0.01 – 100% control range
Vacuum options

Compatible with a variety of non‑corrosive fluids
10 Torr to 3000 PSI full scale
As good as ± 0.125% of full scale accuracy
± 0.08% of full scale repeatability
0.01 – 100% control range

EPC single and dual valve OEM Pressure controllers

15 – 500 PSIA (1 – 500 PSIG)
As good as ± 0.125% of full scale accuracy
± 0.08% of full scale repeatability
0.01 – 100% control range

EP Series OEM electronic pressure meter, by Alicat

Economical & easy to integrate
15 – 500 PSIA (1 – 500 PSIG)
As good as ± 0.125% of full scale accuracy
± 0.08% of full scale repeatability
0.01 – 100% control range

Where you cannot get IO-Link. CODA Coriolis, BASIS 2, our portable MB-, PB-, and LB-Series meters, and anything rated for hazardous areas (neither Class I Division 2, Zone 2 nor C1D1, Zone 0 devices). Need flow control in a classified area? Ask us what to use instead.

IO-Link specifications

Part numbers	Alicat part number segment for IO-Link Class A: -IOLINKA. Alicat part number segment for IO-Link Class B: -IOLINKB.
IO-Link version	V1.1 (IEC 61131-9)
Connector	Powered through an M12 connector, which also provides digital communications. Some IO-Link devices will have an M8 connector, used for serial and analog communications.
Speed	230.4 kbit/s (COM3)
Data	Alicat IO-Link devices support process data in Floating Point (Float32) or Integer (Integer32) format values. The format can be changed from the device screen or over IO-Link.
Cable	Unshielded, three or five conductor, 0.34 mm² or larger, 20 m maximum
Devices per master	One device per port. Your total depends on the master’s ports and its current budget.
Settings backup	The master saves settings and restores them onto a replacement device.
Status light	The LED on the top of an Alicat indicates the device status, and follows NAMUR NE 107 standards for instrumentation.
Media	Gas and liquid
Not available on	CODA, BASIS 2, portable MB-, PB-, or LB-Series, C1D2 (-X), IS-Max, IS-Pro

How do devices connect with IO-Link?

M12 connectors are standard for many IO-Link devices and have the following pinouts.

Pin numbering for M12 Class A and Class B connectors, showing the male instrument connector and the female cable connector for each.

An M8 connector is included on most devices for applications using RS-232 or RS-485 serial communication or requiring an analog interface.

Pin numbering for the M8 connector, showing the six-pin male instrument connector and the female cable connector.

Pinouts, LED colors, fault codes, and wiring diagrams are in the IO-Link FAQ and the IO-Link manual.

Industries using IO-Link

About 71 million IO-Link nodes were installed worldwide by the end of 2025. We added IO-Link as a communication protocol on our main line of devices, to meet the needs of a few of the industries that we serve:

IO-Link setup questions for Alicat devices

Which Alicat products support IO-Link?

Gas, liquid, and pressure devices across our main line, including OEM and dual-valve units. You cannot add IO-Link on CODA Coriolis, BASIS 2, our portable meters, or devices rated for hazardous areas. Ask us what to use instead in a classified area.

How fast is IO-Link on an Alicat device?

The network runs at 230.4 kbit/s. A full set of readings refreshes in about 1.22 ms on P-Series and about 2.4 ms on MC-Series. The difference is how much data each one sends. Control response is a separate number: under 100 ms to setpoint on a typical MC. The Alicat product page lists the exact figure.

Does it meet the industry standard?

Yes. Our devices run IO-Link V1.1, which is IEC 61131-9, and they are tested against the official IO-Link test spec. We file the Manufacturer Declaration for every series publicly on IODDfinder, next to the IODD.

Do I need Class A or Class B masters or devices?

Class A masters supply sufficient power for Alicat Class A devices (meters and small-valve controllers). A Class B master provides an additional, isolated power supply on Pin 5. Alicat Class B devices (like controllers with large Rolamite valves) require a Class B master.

Note that Class B masters can also support Alicat Class A devices. Using a Class B master is sometimes recommended to keep controller valves on a separate power supply, even with smaller valves on a Class A device.

What happens when you replace an IO-Link device on your network?

Your master can save a device’s settings and copy them onto a replacement. Swap a controller at any point in your process, and the new one is programmed with the same gas, the same tuning, and the same units.

Where can you buy an IO-Link device?

Alicat devices are built to your spec, so you can request a quote from us directly or find a local representative to work with. Send your process details and we’ll configure the device to your application. The IODD and manual are free to download if you want to check the fit first.

See all IO-Link FAQs here.

Setting up an IO-Link device

Set up an IO-Link master for your fieldbus. One master connects your devices to PROFINET, EtherNet/IP, EtherCAT, or Modbus TCP.
Run a standard M12 cable, up to 20 m. Unshielded, three or five conductor, 0.34 mm² or larger. You do not need shielded cable, terminators, or address switches.
Load the IODD for your series. Download Alicat IODD files here.
Check your byte mapping. Make sure your master reads all 32 bytes and not a shorter default.

Who can you ask about selecting an IO-Link device?

Our applications engineers are trained to help you. Start with what you’re measuring: gas flow, liquid flow, or pressure. Send us your process details and we’ll work with you to finalize your device selection.

Request a Quote

Ask an Engineer