Machinery builders who utilize pumps and valves in their equipment have various options when it comes to monitoring and controlling these industrial devices. In addition, when working with fluids and gases, there is the need to monitor the state of the process using temperature, pressure, and flow measurements or even valve position feedback. The controls engineer is responsible for maintaining the cost effectiveness of the controls equipment while providing flexibility and monitoring in a highly competitive and increasingly global marketplace.
The development of the distributed modular input/output (I/O) architecture has lowered the cost per point of the controls design and has reduced the time to integrate.
The distributed modular I/O architecture utilizes the vendor-neutral industrial standard, IO-Link (www.IO-Link.com), which allows for easy, universal, smart devices to be integrated. It uses low-cost standard M12 4-wire unshielded cables, which help keep the cost of communication low even while maintaining noise immunity. By implementing a master/slave relationship, up to 8 devices can be connected to one address of an industrial network (Figure A). Distributed modular I/O architectures are IP67, which means they provide I/O that is machine mounted and can withstand all but the most hostile industrial environments in non-hazardous applications.
Saving Costs with Pump & Valve Control
Today many machinery builders utilize a hardwired solution for the control of their pumps and valves in their automated machines. If looking at just the hardware, this seems to be the most cost-effective solution to driving the output.
However, when reviewing the total cost of ownership, the assembly labor, and the cost of hardware (such as controls cabinets, terminal strips, etc), the total cost to control the one valve or pump becomes much higher. Furthermore, if the machine has to be disassembled to ship and install at the customer, the rewiring of the equipment can cut directly into the overall margin of the project. Typical pneumatic valve manifold installations require terminating 25 wires and troubleshooting multiple connectors, making for a time-consuming and costly installation in labor and equipment (Figure B).
By using an industrial network and distributed modular I/O valve manifold connections, the time to install and troubleshoot these connections is dramatically reduced, since the 25 terminations are digitally controlled over a simple M12 connection. The required space in the controls cabinet is reduced by removing the terminal strips and output card, and the time to have a machine running is shortened.
This can allow the machine builder to potentially build more machines per year with the same resources. A recent customer study revealed that it was able to save over $250 per manifold installed on its equipment by moving to this distributed architecture and dramatically reduced the labor involved in the construction of the controls (Figure C).
When attempting to control pumps and valves in an installation less dense than a valve manifold, easy to use I/O devices can be integrated. This allows for simple discrete or even analog control of the pump volume or valve position. In lieu of the terminals in the controls cabinet, standard industrial connectors make for easy work getting the devices up and running. With IO-Link devices from multiple vendors, it’s even possible to keep track of things like counting cycles or measuring exact valve position.
Foolproof Sensor Setup for Monitoring
The machine builder that is incorporating pumps and valves into equipment is being asked more and more to provide additional information to the enterprise level of the factory. Every end-user wants to know about its process — what is failing and what is working well. Equipment customers expect and demand more information to be visible to all levels of the organization.
One way to achieve this information is to integrate analog signals in your controls and sensors, but then you fight noise issues, ground loops, and all of the other intricacies of working with analog devices. You might think this can be easily fixed by implementing an industrial network, but sometimes it doesn’t seem cost effective to have an Ethernet-enabled pressure switch or a Profibus temperature probe. These devices can be more costly, and they take up IP addresses, nodes, and connections for small amounts of data. Every machine builder reuses parts of their old designs in new projects, like always building the same hydraulic power unit. Every build would require you to reprogram the 10 or more settings of the pressure sensor using the pushbuttons, a manual, and about 30 minutes of patience (Figure D).
If you have faced any of these above challenges, there are two distinct advantages to implementing a distributed modular I/O with IO-Link solution. The first advantage is the ability to eliminate your fight with analog signals. The measurement or feedback data is converted to digital inside the device and is packaged as a simple set of bytes that are transmitted by the master over the industrial network, meaning no more noise issues to fight. Costly shielded multi-conductor cables are replaced with standard four-wire sensor cables. And, best of all, no more expensive analog cards in your controls cabinet for just one channel of analog.
The second distinct advantage you gain by implementing distributed modular I/O with IO-Link is the ability to store the parameters of the sensor/probe/transducer, and then download the settings to the device when needed from a PC or the controller. IO-Link devices can be programmed on the fly to virtually any configuration that is determined by the key parameters of the device. This allows for multiple settings to be stored and swapped while running, increasing the flexibility of applications. In the off-chance that the end-user has to replace the device, the master has saved the most recent parameters and can automatically download the settings into the replacement device, no pushbuttons needed.
When machine builders integrate pumps, valves, and monitoring devices, distributed modular I/O can reduce the total cost of ownership of the machine, improve the speed of assembly, and ease the integration process. For end-users, distributed modular I/O can add flexibility to the machine, bring data to all levels of the plant, and ease troubleshooting problems for maintenance crews.
To learn more about distributed modular I/O, download Balluff’s white paper “Distributed Modular I/O Technology Guide: 5 Reasons to Switch to Distributed Modular I/O.”
Will Healy is networking marketing manager at Balluff Inc., part of Balluff GmbH, a leading multinational provider of sensor solutions and systems. Based in Florence, Ky., Balluff Inc. has been supplying innovative and practical sensing solutions for a wide range of applications and industries. For more information, visit www.balluff.com.