Introduction

Modern machine tools for the discrete parts manufacturing industry are complex systems, consisting of subsystems for material preparation (metal removal, material forming, etc.), material handling, fixturing and transfer lines for moving parts from one station to another. Each subsystem, in turn, is itself a complex system, including many sensors, actuators and control elements that receive and transmit electric signals and/or require electric power. To reduce down time in case of failure, most of them use cable assemblies for quick replacement. Proper operation of the system as a whole requires co-ordination of the subsystems, which requires more cables and connectors. As a consequence of this complexity, a large variety of cables and connectors are required for the proper operation of such a machine tool. The increasing number of sensors, actuators and control elements leads to an increasing variety of such cable assemblies. This variety results in increased maintenance costs due to complexity, large spare parts inventory and increased training costs for maintenance personnel.

ISO 23570 prescribes a set of requirements for cables, connectors and parameter selections within these elements, which, if implemented completely, will greatly reduce the wiring complexity and maintenance cost of such machine systems. The manufacturer of such systems will benefit in terms of decreased complexity costs, and the user of such systems will benefit in terms of decreased down time because of decreased parts inventory and simplified maintenance training.

The technology described in ISO 23570 may have applicability to other industries and processes, i.e. there is no intent to restrict it to discrete parts manufacturing.

The following three main areas are addressed within ISO 23570:

— the interconnection of sensors and actuators to the system backbone,
— a hybrid system backbone containing an information path (a fieldbus) and a source of power to the field devices, and
— a power trunk capable of providing power to all the auxiliary motors in the system.

Large power devices, such as spindle motors for metal removal, are not covered by ISO 23570.

Machine tools described in ISO 23570 are subject to constraints imposed by national and international safety standards. ISO 23570 is intended to specify system elements that support the compliance to such standards.

Figure 1 illustrates the system components addressed in ISO 23570. In the figure, the solid cable represents the power distribution bus providing three-phase a.c. power for electric motors. The open cable represents a hybrid communication bus, containing both a fieldbus communication channel and low voltage power.

The centre of the figure shows a control cabinet (3) serving three sets of distribution buses. This box contains the fieldbus communication front end, the low voltage power supplies and the three-phase power supplies.

To the left of the control cabinet are a motor with integrated electronics (1) and a fixed speed motor with a separate motor controller (2). Both units are linked to the control cabinet by both the communication bus and the power distribution bus.

To the right of the control cabinet are a fixed speed motor with an attached motor controller (4), a variable speed motor with an integrated I/O module connected to several sensors and actuators (5), and another I/O module (6) connected to several sensors and actuators, including a hydraulic/pneumatic valve. The I/O module (6) is linked to the control cabinet only by the hybrid communication bus.

In front of the control cabinet are three more units: a motor with integrated electronics (7), another I/O module connected to several sensors and actuators including a hydraulic/pneumatic valve (8), and a remote control terminal (9).

Figure 1 is intended to illustrate the variety of interconnections possible using the elements of ISO 23570.

Figure 1 — System components addressed in ISO 23570

Key

1	motor with integrated electronics (e.g. a stepping motor)
2	fixed speed motor with separate motor controller
3	power distribution and control cabinet
4	fixed speed motor with attached motor controller
5	variable speed motor with integrated I/O module together with sensors and actuators
6	I/O module with a set of sensors
7	motor with integrated electronics (e.g. a stepping motor)
8	I/O module connected to a set of sensors and actuators including a hydraulic/pneumatic valve
9	remote control terminal

ISO 23570‑1 provides the requirements for sensors, actuators, and I/O modules that support this system requirement. ISO 23570‑2 provides the requirements for a shared communication and low voltage power distribution system. This part of ISO 23570 provides the requirements for distribution of power to the low power motor systems.

While significant reduction in maintenance and operational costs may be achieved by adoption of individual parts of ISO 23570, the greatest benefit will occur only if all parts are implemented.

This part of ISO 23570 provides requirements for the distribution of power to the low power motor systems.

BS ISO 23570-3:2009

Industrial automation systems and integration. Distributed installation in industrial applications - Power distribution bus

Current, Under Review

Published:

31 Mar 2023