By Scott Barhorst
Working previously as a controls engineering manager in robotic welding, I have seen some consistent challenges when designing robotic weld cell systems.
For example, the pre-engineered-style welding cells I’ve worked with use many types of tooling. At the same time, space for tooling and cabling is limited, and so is the automation on board, with some using PLC function and others using a robot controller to process data.
One approach that worked well was to use IO-Link in the systems I designed. With its simple open fieldbus communication interface and digital transmission, it brought a number of benefits.
- IO-Link’s digital signals aren’t affected by noise, so I could use smart sensors and connect them with unshielded 4-pin cables.
- Expandability was easy, either from the Master block or by adding discrete I/O modules.
- IO-Link can use the ID of the block to identify the fixture it is associated with to make sure the correct fixture is in the correct location.
- Cabling is simplified with IO-Link, since the IO-Link Master can control both inputs, outputs, and control valve packs. That means that the only cables needed will be 24V power, Ethernet, weld ground (depending on the system), and air.
- Fewer cables means less cost for cables and installation, cable management is improved, and there are fewer cables to run through a tailstock or turntable access hole.
One system I designed used 1 IO-Link Master block, 3 discrete I/O modules, and 1 SMC valve manifold controlled via IO-Link. This tooling had 16 clamps and 10 sensors, requiring 42 total inputs and control of 16 valves. The system worked very well with this setup!
An additional note: It’s good to think beyond the process at hand to how it might be used in the future. A system built on IO-Link is much more adaptable to different tooling when a change-over is needed. Click here to read more about how to use IO-Link in welding environments.