Technical guide · GUEMISA
A non-contact Hall-type angle sensor measures rotation using a magnet and a Hall element, without a cursor touching a resistive track. In mobile machinery, it is chosen when high-pressure sealing (IP69K), resistance to electrical disturbances from the vehicle, two redundancy channels, or a bus output such as CANopen or SAE J1939 are required.
It is not an automatic replacement of the potentiometer: both have long life figures and the choice depends on the signal, the electrical environment and whether the assembly allows a shaft or a two-piece design is more suitable.
Hall effect versus potentiometer
| Criterion | Contactless Hall sensor | Rotary potentiometer |
|---|---|---|
| Principle | Magnet and Hall element; no electrical contact between parts | Cursor on conductive plastic track |
| Life (according to records) | RSA-3200: typical 30 million movements; RSX-7900: over 100 million | IPX-7900: Over 100 million movements |
| Departures | Voltage, current, ratiometric, PWM, CANopen, SAE J1939 | Voltage divider or ratiometric |
| Shaftless design | Yes: two decoupled pieces (RFC-4800, RFE-3200, RFX-6900) | No: it needs a shaft |
| Diagnosis | Signal outside the plausible range in case of error (RSA-3200, RFC-4800, RSX-7900, RSK-3200) | Not applicable to the resistive track |
A potentiometer remains valid when the mounting and signal allow it; the IPX-7900, for example, achieves IP6K9K with wired output. The Hall effect sensor primarily offers contactless operation, diagnostics, and digital interfaces.
Redundancy and functional safety
The datasheets distinguish three configurations: single-channel, partially redundant (one power supply and two outputs), and fully redundant (two power supplies, two grounds, and two outputs). For the RSA-3200, the MTTFd figures are specified per channel for all three configurations, ranging from 1533 years (single-channel, voltage version) to 767 years (fully redundant). The RSK-3200 version is always a two-channel model.
Regarding functional safety, the datasheets are cautious. The mobile analog versions of the RSA-3200, RFC-4800, RFE-3200, and RFX-6900 are described as suitable for safety-related applications according to ISO 13849 after customer validation, with safety data (DCavg…) available upon request. For bus versions, the datasheet recommends consulting the relevant department. The sensor does not replace a comprehensive system analysis.
IP protection
IP67 protection withstands temporary immersion. IP69K, defined in ISO 20653 as IP6K9K, withstands high-pressure, high-temperature water jets, such as those used in pressure washing. In the connectors, the protection also depends on the connection type.
- RSA-3200: IP67 on the shaft side and IP69K on the housing with the electronics.
- RFX-6900 and RSX-7900: IP67 / IP69K, and IP67 with the M12 connector.
- RFC-4800: IP67 / IP68 / IP69, and IP67 with the M12 connector.
- RFE-3200: IP67 / IP68 / IP69K.
- RSK-3200: IP67 / IP69K mounted with o-ring.
Electromagnetic compatibility in vehicles
A vehicle has ignition switches, inductive load disconnects, and radio communications nearby. The specifications on the connectors reflect this.
- ISO 11452: immunity to radio frequency fields; for example, 100 V/m (ISO 11452-2) and 200 V/m (ISO 11452-5) in RSA-3200, RFC-4800, RFX-6900.
- ISO 7637: transient impulses on the power supply and outputs; level 4 on the RSA-3200, RFC-4800 and RFX-6900 power lines.
- CISPR 25: radiated emission.
- E1 according to ECE-R10: homologation for vehicles, which the RSA-3200, RFX-6900 and RSX-7900 data sheet includes in its conformity.
The exact level depends on the version (voltage, current, ratiometric or bus): refer to the data sheet of the specific reference.
Output types
- Analog voltage of 0.25…4.75 V or 0.5…4.5 V: the reserve band at the ends allows detection of a short circuit or a break.
- 4…20 mA current: RSA-3200, RFC-4800, RFE-3200, RFX-6900 and RSX-7900.
- Ratiometric to the 5V power supply: RSA-3200, RFC-4800, RFE-3200 and RSK-3200.
- PWM: RSK-3200, with a duty cycle of 10 to 90% and a frequency of 250 or 500 Hz.
- CANopen and SAE J1939: RSA-3200, RFC-4800, RFE-3200, RFX-6900 (CANopen) and RSX-7900 (CANopen), with 14 bits. In J1939 the RSA-3200 provides position, speed and revolution counter.
Formats: axle, two-piece, and lever
| Product | Format | Signals | Channels | Range | Protection | Temperature |
|---|---|---|---|---|---|---|
| RSA-3200 | Shaft Ø 6 mm; version with lever Z-RSA-M01; 41.5 x 58 mm | Voltage, 4…20 mA, ratiometric, CANopen, J1939 | 1 or 2 | up to 360° | IP67 / IP69K | -40…+125 °C (voltage and ratiometric) |
| RSX-7900 | Shaft Ø 13 or Ø 10 mm, aluminum housing, Ø 79 mm; 300 N on the shaft | 4…20 mA, CANopen | 1 or 2 | 60…360° | IP67 / IP69K | -40…+85 °C |
| RFC-4800 | Two pieces without shaft, Ø 48 mm | Voltage, 4…20 mA, ratiometric, CANopen, J1939 | 1 or 2 | up to 360° | IP67 / IP68 / IP69 | -40…+105 °C |
| RFE-3200 | Two pieces without axle, 41.5 x 59 mm | Voltage, 4…20 mA, ratiometric, CANopen, J1939 | 1 or 2 | up to 360° | IP67 / IP68 / IP69K | -40…+125 °C (voltage and ratiometric) |
| RFX-6900 | Two pieces without axle, Ø 69 mm, aluminum | 4…20 mA, CANopen | 1 or 2 | 60…360° | IP67 / IP69K | -40…+85 °C |
| RSK-3200 | Customer's D-shaft, plastic, 41.2 x 48.4 mm | PWM, ratiometric | 2 | 60…360° | IP67 / IP69K | -40…+125 °C |
The two-piece design, consisting of the sensor and a magnetic marker, has no shaft or bearing, and measurements can be taken through any non-ferromagnetic material. The shaft-mounted option is selected when the rotating element already has a shaft, and the articulation lever attaches to the shaft of the RSA-3200 or RSX-7900.
More than one lap: MB1, MC1 and MZ1
When the movement exceeds one revolution, the MB1-3600, MC1-2800, and MZ1-2200 multi-turn magnetic encoders measure up to 44 revolutions (15,840°) with 16 bits per revolution. They utilize a True-Power-On system with GMR magnetoresistive technology, which counts revolutions even without power, requiring no gears or batteries. They are powered by 12/24 VDC (8–32 VDC) and have CANopen, SAE J1939, or IO-Link outputs; the MC1 and MZ1 also have ratiometric outputs. The MB1 has a 36 mm diameter, IP67/IP69K protection, and a solid or hollow shaft. The MC1 has a 30 mm diameter and IP54 to IP67 protection. The MZ1 has a 22 mm diameter and IP50/IP65 protection, making it unsuitable for pressure washing.
Which GUEMISA products are a good fit?
RSA-3200 analogshaft Ø 6 mm, voltage, current or ratiometric, 1 or 2 channels, IP67 / IP69K.View technical specifications →
RSX-7900 analogshaft Ø 13 or Ø 10 mm, 4…20 mA, 300 N load on the shaft, IP67 / IP69K.View technical specifications →
RFC-4800 analogtwo pieces without shaft, Ø 48 mm, up to 360°, IP67 / IP68 / IP69.View technical specifications →
RFE-3200 analogtwo pieces, 41.5 x 59 mm, up to +125 °C in tension and ratiometric.View technical specifications →
RFX-6900 analogtwo pieces, Ø 69 mm, 4…20 mA, aluminum housing, IP67 / IP69K.View technical specifications →
RSK-3200 PWMtwo channels, PWM from 10 to 90%, 5 VDC, IP67 / IP69K.View technical specifications →
MB1-3600 CANopen44 turns, 16 bits per turn, Ø 36 mm, IP67 / IP69K.View technical specifications →
MC1-2800 CANopen44 turns, Ø 30 mm, IP54 to IP67.View technical specifications →Also the MZ1-2200 CANopen (Ø 22 mm) and the categories Angular displacement sensors and Absolute fieldbus encoder.
Documentation and related cases
- Novotechnik Catalog: Position and Angle Sensors (PDF)
- Novotechnik Sensors for Automotive Applications (PDF, English)
- How an encoder works
- All technical information about GUEMISA
Frequently Asked Questions
What is the difference between partial and total redundancy?
In partial mode, the two channels share power and ground and have two outputs. In full mode, each channel has its own power and ground. The RSA-3200 datasheet provides the MTTFd figures per channel for each mode.
Do Hall sensors comply with ISO 13849?
The data sheets state that the mobile analog versions are suitable for safety-related applications according to ISO 13849 after customer validation. Safety data is provided upon request; system validation is the responsibility of the machine manufacturer.
What does IP69K mean?
Protection against high-pressure and high-temperature water jets, defined in ISO 20653 as IP6K9K. In sensors with M12 connectors, the assembly is rated at IP67 in the connector area.
Which output do I choose if my controller is from a vehicle?
It depends on your inputs. With 5V analog inputs, the output is either ratiometric or 0.5–4.5V. Sensors that offer CAN, CANopen, or SAE J1939 support this functionality. A current input supports an output of 4–20 mA.
Can a Hall sensor measure multiple revolutions?
The ones in this article, with a shaft or in two pieces, measure up to 360°. For multiple revolutions, the MB1-3600, MC1-2800, and MZ1-2200 measure up to 44 revolutions with 16 bits per revolution and retain position without power.
Send us the application, race or reference you have and we will tell you the model and your order code.