We had a similar enquiry from a customer whose drilling equipment sees regular saltwater and corrosive wash-down, on top of the usual explosion-proof requirement. The Hengstler ACURO AX71 is the stainless steel version of the AX70/71 family, built for that combination of hazardous-area and corrosive-environment duty.
This looks simple, but the AX71 uses the same explosion-proof enclosure “D” design as the AX70, just in stainless steel rather than aluminium – worth specifying correctly since the two aren’t interchangeable once the part is on order. It’s an optical absolute encoder with true multi-turn (not battery-backed), on a 70 mm servo-mount 3-hole face with a 10 mm shaft, ATEX and IECEx certified for hazardous areas.
In actual application, the AX71 gives up to 22-bit single-turn plus 12-bit true multi-turn resolution, runs on BiSS, SSI, Profibus, DeviceNet, CANopen or CANLayer2 interface, handles up to 10,000 rpm, and is rated IP64/IP67. Operating range is -40°C to +60°C. It’s commonly specified for oil and gas equipment – top drives, drawworks drums, iron roughnecks, mud pumps, catwalks, pipe handling and cranes – and food and beverage applications where the stainless housing matters for washdown and hygiene.
From our experience, before we quote this, we would normally check whether you actually need the stainless steel housing (AX71) over the standard aluminium AX70, which interface your controller expects, and the hazardous area zone/gas group classification required. Hope this helps.
