M138 Linear Position Sensor

The intrinsically safe M138 is ATEX and IECEx approved for use in potentially explosive gas/vapour and dust atmospheres and mining environments. The M138 is designed for a wide range of industrial applications and is ideal for OEMs seeking good sensor performance in situations where a small diameter, short-bodied sensor is required for operation in hazardous areas. The unit is compact and space-efficient, being responsive along almost its entire length, and like all Positek® sensors provides a linear output proportional to displacement. Each unit is supplied with the output calibrated to the travel required by the customer, from 0-51mm to 0-100mm and with full EMC protection built in. Overall performance, repeatability and stability are outstanding over a wide temperature range. The sensor has a compact 19 mm diameter stainless steel body, is easy to install and set up. The stainless steel mounting flange has two 3.2 mm by 30 degree wide slots on a 25 mm pitch. The stainless steel plunger can be supplied free or captive, with female M4 thread, or springloaded with a ball end. The M138 also offers a range of mechanical options, environmental sealing is to IP67.

Positek intrinsically safe sensors are designed to be used with a galvanically isolated amplifier. Approved galvanic isolation amplifiers (X005) are available from Positek; there is a choice of 0.5-9.5V or 4-20mA transmission outputs.

The sensor can be installed with a cable length up to 1km between the sensor and the amplifier.

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Description

The Positek slim-line mid stroke M138 linear position sensor is ATEX and IECEx approved for use in potentially explosive gas/vapour and dust atmospheres and mining environments. The M138 is designed for a wide range of industrial applications and is ideal for OEMs seeking good sensor performance in situations where a small diameter, short-bodied sensor is required for operation in hazardous areas. The unit is compact and space-efficient, being responsive along almost its entire length, and like all Positek® sensors provides a linear output proportional to displacement. Each unit is supplied with the output calibrated to the travel required by the customer, from 0-51mm to 0-100mm and with full EMC protection built in. Overall performance, repeatability and stability are outstanding over a wide temperature range. The sensor has a compact 19 mm diameter stainless steel body, is easy to install and set up. The stainless steel mounting flange has two 3.2 mm by 30 degree wide slots on a 25 mm pitch. The stainless steel plunger can be supplied free or captive, with female M4 thread, or springloaded with a ball end. The M138 slim-line mid stroke sensor also offers a range of mechanical options, environmental sealing is to IP67.

Positek intrinsically safe sensors are designed to be used with a galvanically isolated amplifier. Approved galvanic isolation amplifiers (X005) are available from Positek; there is a choice of 0.5-9.5V or 4-20mA transmission outputs.

The sensor can be installed with a cable length up to 1km between the sensor and the amplifier.

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Positek offers a range of options for its standard sensors. Each sensor is manufactured to suit each customer's preferences. If your requirement is outside the options given below, Positek can modify/ redesign a sensor to suit your specific requirement. Standard options are available as below:

 

Measurement Range

Factory set to any length from 0-51mm to 0-100mm in increments of 1mm. For example, if your application requires 3" (76mm) measurement, then Positek will manufacture the sensor specifically for this length. The mechanical length and calibration will be set up for 76mm.

 

 

Connector/Cable Options

Option Option Code
Cable with axial gland, IP67 L (3 core cable)
LQ (5 core cable)
Cable length - The standard length of cable supplied with a Positek position sensor is 50cm although you can specify any length you require up to a maximum of 15,000cm Specified in cm after the L/LQ e.g. L200 for 200cm cable from axial cable gland

 

Mounting Options

Option Option Code
Front flange mount (not optional, must be fitted) N
Body clamps P

 

Push Rod Options

Option Option Code
Spring loaded (extended) R
Dome end on plunger T
Non captive plunger (not with options "R" or "T") U

 

<+/-0.1% FSO Linearity error Option Code
Z650

Intrinsic Safety

ATEX/IECEx approval

This sensor is ATEX/IECEx approved to:
Ex I/II M1/1GD
Ex ia IIC T4 Ga (Ta = -40°C to + 80°C )
Ex ia 111C 20 T135°C Da (Ta = -40°C to + 80°C )
Ex ia I Ma (Ta = -40°C to + 80°C )
This designates the sensor as belonging to; Groups I and II: suitable for all areas (including mining), Category M1/1 GD: can be used in areas with continuous, long or frequent periods of exposure to hazardous gas (Zones 2 to 0) and dust (Zone 20), equipment remains energised.

Gas:
Protection class ia, denotes intrinsically safe for all zones.
Apparatus group IIC: suitable for IIA, IIB and IIC
explosive gases.
Temperature class T4: maximum sensor surface
temperature under fault conditions 135°C .

Dust:
T135°C: maximum sensor surface temperature under fault conditions 135°C.

Ambient temperature range extended to -40°C to +80°C.

Galvanic Isolation Amplifier

Intrinsically safe sensors must be used with a galvanically isolated amplifier with safety parameters not exceeding:- Ui: 11.4V, Ii: 0.2A, Pi: 0.51W. Sensor can be installed with a cable length up to 1000m maximum from the amplifier, cable capacitance and inductance can be up to:- Capacitance: 200 nF max, Inductance: 810 μH max.

Approved amplifiers are available from Positek; there is a choice of 0.5-9.5V or 4-20mA transmission outputs.

 

Dimensions

Body Diameter 19mm
Travel Any stroke from 0-51mm to 0-100mm (e.g. 76mm)
Independent Linearity <±0.25% at 20°C 
<±0.1% available on request
Temperature Coefficient <±0.01%/°C Gain & <±0.01%FS/°C Offset
Resolution Infinite
Noise

<0.02% FSO

Frequency Response

>10KHz (-3dB)

 

Temperature Limits

Operating -40 to +80°C
Storage -40 to +125°C

 

Other

EMC Susceptibility EN 61000-6-2
EMC Radiated EN 61000-6-3
Vibration IEC 68-2-6: 10g
Shock IEC 68-2-29: 40g
MTBF 350,000 hrs 40°C Gf
Sealing IP67
Electrical Connections Screened cable