1. Overview: 

Sensor system 

Components of AN1850 50 mm proximity Sensor system:

AN1850  Probe ;

AN1880 Extension cable;

AN1800 50mm proximitor.



Sensor system output is proportional to the voltage signal changing with the gap between the probe end and the measured conductor surface. It can not only be used for static (shaft position) signal measurement, but also used for dynamic (shaft vibration) signal measurement. It is mainly used for the shaft vibration, shaft displacement, key phase, speed and eccentricity of film sliding bearing rotating machinery.

AN1850 50 mm proximity   Sensor system follows the 670 Standard made by American Petroleum Institute (API) for this kind of Sensor completely. All AN1850 50 mm proximity   Sensor systems can reach specified performance criteria and the probes, extension cables and proximitors are fully interchangeable, no independent matching or calibration is required. The Sensor system is safe and explosion-proof in essence and it will not cause spark under electrical operation.


AN1850 50 mm proximitor has two types of mounting base plate. It can select DIN35mm guide rail or traditional panel for mounting. The base plate is insulating when either kind of mounting method is adopted and no separate insulating plate is required.

AN1850 50 mm proximitor housing is cast from aluminum. To shield external interference, the housing and the signal public terminal (signal earth) are connected inside the proximitor. As the mounting base plate and guide rail seat are made of insulating engineering plastics, it can be ensured that the proximitor housing and earth are isolated when a proximitor is mounted, the radio interference resistance ability is improved and the European RFI/EMI anti-radiation standards can be reached.

AN1850 50 mm proximitor uses Spring Loc terminal which can be fixed automatically, and wiring can be realized without erecting tools. Besides, it will not get loose for bolt fixing is not required.

Fault tolerance of AN1850 50 mm proximitor: any wiring fault of supply terminal, common terminal (SG) and output terminal can not damage the proximitor, and it has the function of power polarity error protection and output short-circuit protection.

Probe and extension cable 

All parts of AN AN1850 50 mm probe are connected through mechanical deformation to ensure its stability and reliability in severe environment.

For all connectors of AN1850 50 mm probe and AN1880 extension cable, gold-plated copper connectors are adopted as per MIL-C-39012 (the military specification of the U.S.). These connectors only need to be fixed manually (connectors can be locked automatically), and special mechanical locking device can prevent loose connection.

Connectors at two ends of AN1880 extension cable are different. The connector with male thread (adapter) is coupled to probe, while the connector with female thread is coupled to proximitor. Fluoroplastics resistant to high and low temperature and chemical corrosion are used for cable insulation and sheath.

2. Technical Specifications

Linear range: 25mm (1in)

Linear range is from the position about 3mm (120mil) from surface of the target: 3~28mm (120~1100mil).

Sensitivity: 0.394mV/μm (10mV/mil)

The sensitivity is less than 0.394mV/μm (10mV/mil) ±5% within the linear range of 25.0mm (1000mil) including interchangeability error.

Probe installation clearance: 16mm (640mil).

Frequency response:

0~3KHz, typical value of 0~-3dB, 300m (1000 feet) field wiring.

Power supply:

DC supply: -24VDC (-23~-26VDC);

Power consumption: current consumption is no more than 20mA.

 Requirements for target:

Diameter of target (width of toroid): 100mm (4in) not less than 2 times of diameter of probe head; calibrate it on site if the detected surface is small.

Calibration of target material: 40CrMo steel/AISI4140 steel; calibrate it if the target material is inconsistent.

Interchangeability error:

Error of interchangeable probe of the same type is ≤±5%;

Error of interchangeable extension cable of the same type is ≤±5%;

Error of interchangeable proximitor of the same type is ≤±5%;

Field wiring:

Using 0.5~1.5mm2 three-core shield cable; distance between proximitor and probe is less than 300m (1000 feet). When using a longer cable, signal suffers from attenuation, which needs calibration on site.

Environmental limitations:

Probe and extension cable:

Probe head pressure: less than 12MPa

Temperature: -50℃~+170℃(-58oF~+338 oF)

Working medium: air, oil, water, ammonia hydroxide.


Temperature: -35℃~+85℃(-31oF~+185 oF)  

Relative humidity: 0~95% (non-condensing)

Physical characteristics:

Probe head material: PPS - PPS engineering plastics material resistant to high temperature;

Probe housing material: AISI 304 stainless steel (SST);

Probe housing torque: standard directly installed probe: 45N.m

Reversely installed probe: 10 N.m

Extension cable: 75Ω coaxial cable (covered by fluoroplastic insulating sheath);

Armoring of probe and extension cable: 304 SST stainless steel;

Proximitor material: A308 aluminum;

System length: 5m or 9m including extension cable;

Minimum turn radius of cable: 25mm (1in);

Connector material: gold-plated brass.

Executive standards

The United States Petroleum Association Standard: API 670

Safety certificate: CE;

Protection level: IP65;

Explosive-proof grade: ATEX: Ⅱ2G ExdⅡCT4/BT4 

Anti-electromagnetic interference: EMC/LVD

Refer to EN55011\ EN 61010\ EN50081\EN50082.

3. Ordering information

AN1850 50 mm standard proximity probe 

Metric system: AN1850 /M   M14x1.5 thread


British system: AN1850 /I   1/2″-20UNF thread


Standard model:

AN1850 /MR-01-05-10-00-00

AN1850 /MR-01-05-50-00-00

AN1850 /MR-01-05-90-00-00

AN1850 /IR-01-05-10-00-00

AN1850R /I-01-05-50-00-00

AN1850R /I-01-05-90-00-00

A: Unthreaded length

01—10mm / 1/2 in

02—20mm/ 1in

Increase by 10mm (0.5in) progressively when placing an order.

Max. unthreaded length shall be 20mm/0.8in less than length of probe housing;

Min. unthreaded length is 10, max. housing length minus 1in;

B: Total housing length (including unthreaded length):

05—50mm / 2 in

10—100mm/4 in

Total housing length is increased by 10mm/0.5in progressively;

Max. housing length is 250mm/10in and min. is 25mm/1in.

C: Total probe length

05-0.5m (1.6 feet)

10-1m (3.3 feet)

50-5m (16.4 feet)

90-9m (29.5 feet)

D: Cable options

00 - Unarmored

01 - Armored

E: Approval institution

00 - No requirement

01 - ATEX: Ⅱ1 G Exia ⅡC T4

XX – Other

AN1800 50mm proximitor


Standard model:



B: Total cable length (probe + extension cable)



C: Installation mode

00 - DIN35mm guide rail installation

01 – Base plate installation

D: Approval institution

00 - No requirement

01 - ATEX: Ⅱ1 G Exia ⅡC T4

XX – Other


AN1880 extension cable


Standard model:



A: cable length





B: cable options

00 - Unarmored

01 - Armored

C: approval institution

00 - No requirement

01 - ATEX: Ⅱ1 G Exia ⅡC T4

XX – Other

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