Hengstler ACURO AX73 – Absolute Encoder

We received an enquiry from a customer with equipment in a chemical processing plant where the encoder had to be explosion-proof, handle constant chemical exposure, and still give accurate high-resolution position feedback. The Hengstler ACURO AX73 is built for that combination of requirements.

This looks simple, but “corrosion resistant” is a specific spec here, not a general claim – the AX73 is built in high-grade 1.4404/AISI 316L stainless steel, which is the more corrosion-resistant grade used for genuinely harsh chemical or marine environments (a step up from standard 304-grade stainless). It’s ATEX and IECEx certified for gas and dust hazardous areas, and uses a true geared optical multi-turn mechanism (not battery-backed).

In actual application, the AX73 gives up to 22-bit single-turn plus 12-bit multi-turn resolution (depending on interface), runs on SSI, BiSS or Profibus interface, and is rated IP66/67. It’s built to the same ACURO Industry high-precision standard as Hengstler’s non-Ex industrial encoders, so you’re not trading away accuracy for the explosion-proof rating.

From our experience, before we quote this, we would normally check the hazardous area zone/gas group classification required, which interface your controller expects (SSI/BiSS or Profibus), and the specific chemicals or media the housing will be exposed to. Hope this helps.

Series: ACURO AX73
Type: Absolute rotary encoder, optical, true geared multi-turn, explosion-proof (ATEX and IECEx certified for Gas and Dust)
Housing: High-grade stainless steel, 1.4404 / AISI 316L (extreme corrosion resistance)
Resolution: Up to 22 bits single-turn + 12 bits multi-turn (depending on interface)
Interface: SSI / BiSS, or Profibus
Ingress protection: IP66/67
Approvals: ATEX, IECEx
Note: Built to Hengstler’s ACURO Industry high-precision standard

Download Hengstler ACURO AX73 Absolute Encoder information here

SSI/BiSS interface:
Datasheet: AX73-BiSS_SSI_Datasheet_241016_EN.pdf
Installation Manual: AX73-BiSS_SSI-IP67_Inst_2-539-198_3151222.pdf

Profibus interface:
Datasheet: AX73-Profibus_Datasheet_241016_EN.pdf
Installation Manual: AX73-Profibus-IP67_Inst_2-539-196_3151222.pdf

Please confirm which interface you need (SSI/BiSS or Profibus) so we send the matching documentation.

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