March 28, 2017
You’re designing a new machine. Should you use IO-Link or AS-interface (AS-i)? Yes.
Yes, you should use the one appropriate to the task at hand. There’s never a substitute for doing the engineering.
Use AS-i for:
- A long string of pushbuttons (as along a conveyor).
- A long string of Emergency Stop pushbuttons (as along a conveyor).
- A simple analog device with relatively slow update times.
- Any arrangement of simple I/O devices in a network. (For “simple,” understand “low data.”)
- When functional safety over the network is needed. AS-I Safety at Work can transparently connect to PROFIsafe.
Use IO-Link for:
- Intelligent sensors and actuators. (For “intelligent,” understand “high data.”)
- Where point to point wiring is acceptable.
- IO-Link does not yet have a functional safety specification, although it is being worked on.
By high and low data, I mean the volume of parameters accessed for configuration or asset management. IO-Link excels when there are high data requirements.
Either technology can work with any fieldbus or connect directly to an I/O rack. There are even products to connect IO-Link to an AS-i network.
| AS-i | IO-Link | |
| connection | network | point-to-point |
| device complexity | low data | high data |
| functional safety | yes | planned |
| fieldbus integration | any | any |
Do the engineering – use the right technology for the right task: AS-i for a network of low data devices, IO-Link for point-to-point connections of high data devices.
–Carl Henning