Test, test, test. Millimetre-precise position accuracy for long travels
Richard Habering | 14. August 2020
News from the smart plastics test laboratory
On 11.08.2020 with very warm temperatures (+35°C) outside, BTG and us as well as the EC. PP (positioning system for long travels). entered the hot phase. The system presented in spring 2020 now takes the next major step in readiness towards high volume production. The aim is to deliver the system from stock. In the following blog you can learn more about the product, its benefits and how the assembly on the test rig went.
Why was EC. PP created?
The EC. PP is a module of the EC. PR system, which in addition to determining the position also determines the push/pull forces of an e-chain. The second module of the EC. PR is the EC. P (formerly PPDS = push pull detection system), which only undertakes the push-pull force measurement of an e-chain. The EC. P has already established itself worldwide in the crane sector. So we needed a product to generate our own position signals. Before development began, we discussed with customers the possibility of reading the position data directly from the crane’s control system. This would have made an additional positioning system superfluous. During these discussions, an astonishing number of customers mentioned the considerable assembly effort required for precise positioning systems (4-5 days). We were also aware that the installation location is quite congruent with that of an energy supply system. Unfortunately, the existing positioning systems cannot be integrated into an energy supply system. Many customers would welcome a combined system. We understood the signals. Yes, we did. So, the idea of the EC. PP was born
What is an EC. PP?
Development together with BTG
BTG, an established company in the crane sector, has been developing and selling RFID-based positioning systems in the crane industry for many years. These are delivered worldwide for STS (Ship to Shore). RTG (rubber tyred gantry) and RMG (rail mounted gantry) cranes are used.
In a joint project the current BTG system was further developed and the EC. PP was born.
The test setup on 11.08.2020
The “beacons” (small, white, wire-fed transmitters) are placed at 500mm intervals on the outside of the igus standard guide trough. They transmit their position with millimetre accuracy to the antenna (grey bar), which is mounted on the floating moving end.
In the series, the 2m segments of the steel guide trough will already contain the wired and pre-assembled transmitters. No additional work is required when installing the guide trough system on the crane.
BTG always transmits the position data via Profinet directly to the crane’s control system. In the case of Siemens systems, an appropriate GSD file is delivered. At the same time, the system transmits the position via RS 485 protocol to the igus ICOM system.
EC. PP, the system knows the exact position of the crane trolley or the moving end of the e-chain down to the millimetre. Each position is assigned a specific push-pull force. If the maximum push-pull force assigned to a position is exceeded, the system switches off automatically. This can prevent potential and expensive consequential damage to the crane.
After 4 hours of assembly time, a lot of sweat and countless bottles of water, the system control (Siemens S7/1200) displayed the position of the e-chain with millimetre accuracy.
Conclusion
What should actually only complete the EC. PR turns out to be a desired extra for many crane manufacturers and operators. EC. A PP system on the energy supply trough alone saves 4-5 days during crane assembly. Furthermore, a rotary measuring system (travelling wheel for distance measurement) can be dispensed with. This is not very accurate and is also rather slow during data transfer.