22 Jul 2024


Servodrive strips out STO to cut costs

The German drives-maker Metronix – owned by the US-based Apex Tool group – is offering a low-cost servodrive which strips out the usual Safe Torque Off (STO) function to cut costs.

The ARS 21xx/23xx SE drive is said to deliver a peak current capability up to twice that of many rival drives – allowing faster acceleration – as well as offering universal encoder interfacing, at a lower cost than most of its competitors.

The drive is aimed at applications that do not need advanced functional safety, and where a simpler disabling mechanism based on electrical contactors is sufficient. In many applications, safety disabling features are unnecessary because the drive is in a closed system that cannot be accessed during operation.

Metronix suggests that the drive could appeal to machine-builders who are asked by customers to fit a preferred make of PLC. Because of the complexity and costly commissioning needed for some fieldbus-based safety concepts, external safety devices might be preferred. Also, some machine-builders have not adopted drive-integrated safety and continue to use external safety devices, while others offer proprietary safety systems.

The 54 or 69mm-wide panel/cabinet-mounting drives are available in six single- or three-phase continuous output power ratings from 0.5–6kVA (with peak output powers from 1–12kVA).

They have integrated line and motor filters as well as brake choppers and braking resistors.

The drives have an overcurrent capability of four times their continuous output rating, compared with two-times overcurrent ratings offered by many other servodrive manufacturers. Metronix says that this allows the speed of moves and the throughput of machines to be increased by 17–25%, as well as boosting productivity by 5–7% in typical continuous applications.

The universal encoder interface allows connection to resolvers, analogue/digital incremental encoders, and single-/multi-turn absolute encoders such as Hiperface or EnDat. Standard communications interfaces include Can.

A Windows-based software tool is available for parameterising and analysing the new drives. For more complex applications, Metronix offers a motion controller which can be integrated easily.