Simple Differential Equation

Multicore cables and passive junctions failed

Initially, the customer wanted to connect the signals of sensors and actuators to the fieldbus gateways in the control cabinet using passive junctions and multicore cables. However, this solution didn't meet all of the specified requirements. The costs of the cable lengths and the extensive wiring effort involved had a negative effect on the overall cost. Many cables for the passive junctions would have had to be prepared manually and then connected again to the I/O modules in the control cabinet. Commissioning would have been particularly prone to errors as well as being time consuming. The solution would also have been very expensive and difficult to maintain.

Troubleshooting during cable inspection would have initially presented a lot of problems: As the types and models of the sensors installed are the same, the cable markings are also identical apart from one or two digits. Assignment errors were therefore bound to happen. The search for and rectification of wiring errors would in turn be very time consuming and complex. The customer recognized this before the solution was chosen and obtained further advice from Turck.

IO-Link solution fast and efficient

Turck could offer a space saving solution that simplified the wiring of the production workbenches and which nevertheless could be implemented cost effectively. The system also allowed the implementation of diagnostics right down to the sensor level.

The customer used a Siemens controller with Profibus-DP. Turck consequently offered a BL20 Profibus gateway for the control cabinet in conjunction with IO-Link master modules. Turck's IO-Link compatible TBIL junction boxes are ideal for connecting the sensors and actuators in the field. These I/O hubs use IO-Link to bring up to 16 binary signals to the IO-Link master via a standard sensor cable. The 16-bit process signal of the IO-Link protocol is therefore not used for an analog process value, but for transferring 16 individual switch signals for digital input or output signals. As the TBIL I/O hubs offer protection to IP67, they can be mounted directly in the field as close as possible to the sensors and actuators. IO-Link is a digital protocol that allows the use of standard three-wire cables, which eliminates the need for any expensive shielding and lengthy cable commissioning.

Efficient and transparent network structure

This network structure, consisting of I/O hubs and Profibus DP gateways with IO-Link master modules, enabled the user to avoid the need for any time consuming wiring in the control cabinet as well as making savings in the terminals, expensive cables, and space required. The solution also provided an outstandingly simple and clear network structure that prevented faults already at the installation stage.

If any faults occurred later, however, maintenance was simple thanks to the use of IO-Link. The location of faults can be identified right down to the individual field device and differentiated between a wire break or a short circuit. The central configuration of the entire system from the controller ensures the central availability of all relevant information. This simplifies both maintenance and documentation.

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