Press release

 

15.06.2016

Reduce cable spaghetti in machines

There is no way to avoid wiring electrical drives for format changeovers. It is an area that requires detailed planning and consideration – long before the engineer starts erecting the machine. Selecting the correct wiring method can save a great deal of time and trouble during setup and servicing.

There are two fundamentally different approaches to connecting and wiring intelligent drives. Usually, the topology combines a number of drives into units (e.g. subdivided according to the process steps or their functions in the machine). The first option is to wire the drives directly in series or a ring configuration; the second is to wire them indirectly via a hub. The most effective method depends on the number of positioning drives in the machine and the machine design but either is possible. Here is a brief description of the two methods.

Directly wired positioning systems – without bus distributor – for automated format changeoverzoom
Directly wired positioning systems – without bus distributor – for automated format changeover

Direct wiring of positioning systems in series or ring configuration

The positioning systems receive their commands directly from the control unit. They change the specified formats at the touch of a button. No bus distributor is required between the positioning system and control unit because the intelligent drives have bus communication on board. Direct wiring combines a number of drives into a unit by connecting them in series. The first positioning system is connected to the control unit by a cable. The bus signal is looped through to the second positioning system and then to the next. In principle, this can be continued for any number of positioning systems (for Ethernet-based buses).
When connected in a ring configuration, the last positioning system in the series is also connected to the control unit by a cable (for Ethernet-based buses). The advantage of this method is that the bus remains active and the devices can communicate with the control unit if one of the cables in the series should develop a fault. The power supplies to the motor and the control unit electronics are galvanically separated and use a separate cable. This has several advantages: First, the motor voltage can be routed via an emergency stop switch, which improves machine safety. Secondly, the bus signal remains active. As a result, the control unit can query the device status at any time – even if there is no power supply to the motor. Using a separate supply voltage cable to provide the two power supplies has the further advantage that a simple cable can be used rather than a high quality, expensive hybrid cable.

Indirect wiring of positioning systems via a hub

Wiring positioning systems indirectly via a hub allows them to be connected using a single cablezoom
Wiring positioning systems indirectly via a hub allows them to be connected using a single cable

Indirect wiring via a hub really comes into its own when eliminating cable spaghetti is the priority. The positioning system is connected using a single cable and therefore provides greater clarity and transparency. Above all, it reduces complexity and the time required for wiring each positioning system (just one cable per device) in the machine during setup. Moreover, it minimises the potential for errors (only one socket on each device). However, the standardised y-coded cable (for Ethernet-based buses) must be spliced beforehand for bus communication and power supply. The bus communication cable is connected to the hub which is then connected to the control unit. The power supply cable is connected to a power distributor (power adapter). The hub can also be used to define units of generally up to eight positioning systems (depending on the number of ports on the hub).

Boost your flexibility with modular positioning systems from halstrup-walcher

The PSE 325_3210-14 positioning system for indirect wiring with just one cable
The PSE 325_3210-14 positioning system for indirect wiring with just one cable

A variety of factors will influence the choice of wiring method. Opinions on the “correct” method can differ even within a company. halstrup-walcher offers both direct and indirect wiring solutions for positioning systems. These can be used with standard industry hubs and standard bus cables (for Ethernet-based buses). This offers machinery manufacturers the flexibility to select hubs and cables from a range of suppliers. When comparing the costs of the two solutions, experience has shown that the costs for the hub approach are the crucial factor. The most suitable, cost-effective and efficient wiring solution must be determined during the design phase itself.
Designers who value a tidy machine can now also connect the PSE/PSS/PSW positioning systems from the 3-series indirectly via a hub. The advantages of the modular positioning system apply here as well: Absolute measuring system on the output shaft (without battery), longitudinal or horizontal construction, torques from 1 .. 25 Nm, flexible choice of three protection classes and ten buses with virtually identical external dimensions.


 
 
 
 

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