Hengstler

Manufacturer information and published contact details

Hengstler contact details

Head office

Uhlandstrasse 49
78554 Aldingen
Germany

Telephone +49 7424 89 000

Email info@hengstler.com

Website hengstler.com

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Contact details as published by Ralliant Corporation (Hengstler GmbH, part of Hengstler-Dynapar), checked 2026-10-30. Specify Motion is not affiliated with Ralliant Corporation (Hengstler GmbH, part of Hengstler-Dynapar).

Hengstler product lines

Who Hengstler is

Hengstler GmbH is a German manufacturer of rotary encoders and other industrial components, based in Aldingen in Baden-Württemberg. Engineers mostly meet the name through its two encoder families: ACURO for absolute encoders and ICURO for incremental encoders. Alongside encoders, the company still makes the counters, relays and printers and cutters that built its reputation, and it lists ATEX and ISO 9001 among its credentials.

For a design engineer, Hengstler sits in the established European industrial encoder tier: 58 mm housings with standard synchro and clamping flanges, a wide choice of fieldbus and Industrial Ethernet interfaces, and a strong line in servo motor feedback and safety-rated encoders.

History and ownership

Hengstler is one of the oldest names in motion sensing. Its own history page records the following:

• 1846: Johannes Hengstler opens a workshop in Aldingen making clock gongs.
• 1920s: the company develops what it describes as the world’s first zero-settable counter, later used for decades in tape recorders.
• 1950s: the plastic plug-in Counter System 400 gives it a leading position in counters.
• 1975: positively driven safety relays are introduced.
• Early 1990s: Hengstler develops its Opto-ASIC technology, the optical scanning chip behind its encoders.
• 2021: the company celebrates 175 years.

Ownership has changed several times in recent decades. Hengstler now forms part of Hengstler-Dynapar, together with the encoder brand Dynapar, and Ralliant lists Hengstler-Dynapar in its Sensors & Safety Systems segment. Ralliant describes the business as having moved “from Danaher to Fortive and now to Ralliant”. Ralliant is listed on the New York Stock Exchange (NYSE: RAL) and reports about 7,000 people across more than 50 locations. Hengstler’s own website carries the Ralliant terms and conditions and refers to the Ralliant Business System.

Encoder portfolio

The pages below link to our series records, which summarise the published figures for each family.

Absolute encoders (ACURO)

• The ACURO AC58 is the general-purpose 58 mm absolute encoder, in single-turn and multi-turn versions. It offers up to 34 bits in total (22-bit single-turn and 12-bit multi-turn, depending on interface) and a very wide interface list: SSI, BiSS, EtherCAT, PROFINET, PROFIBUS, CANopen, DeviceNet, Interbus and others. The EtherCAT version is ETG certified, updates down to a 62.5 µs cycle and is sealed to IP67.
• The ACURO AX73 is the explosion-proof version, with a 22-bit optical sensor in a 76 mm stainless steel housing, certified for gas and dust atmospheres and rated -40 to +70 °C.
• The ACURO AR62/63 family is built for heavy and marine duty. Hengstler’s maritime version is approved under DNV GL classification, sealed to IP67 and IP69K, and used on deck cranes, winches and azimuth drives.

Servo motor feedback

• The ACURO AD36 is a motor feedback encoder with 22-bit single-turn and 12-bit geared multi-turn resolution, SSI or BiSS plus 1 Vpp sine/cosine, and an 8 mm through hollow shaft. Hengstler states that it fits where a size 15 resolver would.
• The ACURO AD37 is a 29 mm deep safety encoder certified to SIL 3 / PL e Cat. 3, with 20-bit single-turn and 12-bit multi-turn resolution and position plus winding temperature sent over one cable up to 100 m.

Incremental encoders (ICURO)

The ICURO RI58 is the universal 58 mm incremental family, with up to 10,000 lines (40,000 steps with edge evaluation), IP67 and a long list of flange and connector options. Variants include the hollow-shaft RI58-H for shafts up to 12 mm and the high-temperature RI58-T, rated to 100 °C.

Technologies and standards

Hengstler’s encoders are built around its own Opto-ASIC optical scanning chip, which integrates the photodetectors and signal processing. The interface spread matters in practice. A drive maker can take the AD36 on BiSS, a machine builder can connect an AC58 directly to EtherCAT or PROFINET, and a process plant can use the AX73 on SSI or PROFIBUS inside an ATEX zone. The AD37’s SIL 3 / PL e rating puts it among the encoders that can feed safety functions such as safe speed or safe position without a second encoder. Hengstler’s knowledge centre covers the background on SSI and BiSS, HTL versus RS422 outputs and single-turn versus multi-turn resolution.

Industries served

Hengstler names applications across machine tools and CNC axes, packaging, injection moulding, sawing and textile machines, servo motors and drives, rotary indexing machines, cranes and winches, ships, oil and gas and petrochemical plants, paint shops, bottling plants and grain mills. Ralliant adds robotics and medical equipment as target markets for Hengstler-Dynapar.

Global and UK presence

Hengstler GmbH is run from Aldingen, which is the only address on its contact page. The site’s contact page does not list a UK subsidiary or UK distributor, so UK buyers generally deal with the German head office or its product inquiry form, with its sister brand Dynapar in the same Ralliant business.

What to send when specifying a Hengstler encoder

Have the flange and shaft type ready (synchro, clamping or hollow, and diameter), single-turn or multi-turn, resolution, the interface your controller reads, supply voltage, speed, IP rating, temperature range, and any safety or ATEX requirement. For motor feedback, add the motor shaft taper or bore and the drive’s feedback protocol.

Specify Motion is independent of Hengstler and Ralliant. Our engineers can help source Hengstler encoders or propose equivalents from our supply network on published figures; see find a replacement or the encoders hub.

Hengstler history: key dates

1. 1846Johannes Hengstler opens a workshop making clock gongs in Aldingen
2. 1920sDevelops what it describes as the first zero-settable counter
3. 1950sPlastic plug-in Counter System 400 gives it a leading position in counters
4. 1975Introduces positively driven safety relays
5. Early 1990sDevelops its Opto-ASIC encoder technology
6. 2021Marks 175 years in business

Hengstler encoders

Optical absolute encoder

ACURO AC58

58 mm industrial absolute encoder in single-turn and multi-turn versions with up to 34 bits total (22-bit single-turn, 12-bit multi-turn, depending on interface) and one of the widest interface choices in the class, from SSI and BiSS to EtherCAT and PROFINET.

Optical absolute encoder

ACURO AD36

Motor feedback absolute encoder with 22-bit single-turn and 12-bit geared optical multi-turn resolution, SSI or BiSS plus 1 Vpp sine/cosine, an 8 mm through hollow shaft and 10,000 rpm continuous; it is installation compatible with a size 15 resolver.

Optical absolute encoder

ACURO AD37

Compact safety motor feedback encoder, 29 mm deep, with 20-bit single-turn and 12-bit multi-turn resolution, ±36 arcsec accuracy and SIL 3 / PL e Cat. 3 certification, sending position and winding temperature over one cable up to 100 m.

Optical absolute encoder

ACURO AX73

Explosion-proof absolute encoder with a 22-bit optical sensor in a 76 mm stainless steel housing, certified for gas and dust atmospheres, IP67 and rated -40 to +70 °C, with SSI, BiSS-B, BiSS-C or PROFIBUS.

Optical incremental encoder

ICURO RI58

Universal 58 mm incremental encoder family with up to 10,000 lines (up to 40,000 steps with edge evaluation), IP67 and many flange and connector options; hollow-shaft RI58-H takes shafts up to 12 mm and the RI58-T runs to 100 °C.