Sensata claims first stackable explosion-proof multi-turn encoder

By Warren Miller, contributing writer

Encoders measure and control the motion of operating devices in everything from medical and laboratory settings to automated factories and electric motors. Some applications require encoders to function in harsh and possibly even destructive conditions, such as extreme temperatures or high vibrations. Sensata Technologies believes that it has developed the perfect solution to challenging environments that require multi-turn encoders. The company claims that BEI Sensors’ model MAAX is the first explosion-proof stackable multi-turn encoder specifically designed for oil and gas applications.

The MAAX encoder is ATEX- and IECEx-certified, the European and international standards for explosive material certification, and can operate in explosive Class 1, Division 1, and Zone 1 environments. The encoder is shock- and vibration-resistant, can operate in field temperatures between −30°C and 65°C, and all of the device’s exposed surfaces are either hard anodized or stainless steel to combat corrosion.

The MAAX offers Profibus, CAN, and SSI outputs, provides 16 bits of resolution, and is outfitted with a 20-mm-diameter integrated coupling for rigid mounting purposes, thereby reducing strain on the device’s bearings and providing a secure attachment for hazardous area conduit fittings, according to the company.

Additionally, its stackable design makes the MAAX well suited for applications that require encoders to work in tandem to share data or to provide redundancy. Multiple devices can be linked using the Profibus interface, eliminating the need for running a control cable from the patch panel to each individual device.

Absolute multi-turn encoders like the MAAX are a good fit for the challenges of oil and gas applications such as pipe-handling equipment and top drives. The single-unit system makes installation simple and LED status lights allow the monitoring of its functionality during both installation and operation.

Other features include a terminal box that simplifies installation by allowing the unit to be pre-wired and tested prior to assembly, a flexible internal connector in the terminal box to simplify cable gland installation, and standard captive screws with the terminal box, which is tethered to the encoder body for safety, said the company.