Schreiber SM30 LVDT sensor – Integrated electronics M30×1.5

The Schreiber SM30 series has eight electrical models. Each one determines the type of output signal and the direction of variation with respect to the core's movement.

Rising signal: increases when the stem moves toward the sensor connector. The falling version reverses this relationship.

The PLC's analog input must support the selected signal. The power supply must meet the reference requirements.

The Schreiber order code identifies the electrical model, nominal stroke, linearity class, and, where applicable, a mechanical option.

Structure: SM30X.STROKE.LINEARITY.OPTION

• X = 1 to 8: output type and signal direction.
• Stroke: 5, 10 or 15 mm.
• Class .1: linearity 0.25%.
• Class .2: linearity 0.5%.
• Option .T: execution as a probe.
• Option B: bellows execution.

The table details the code combinations for standard mobile kernel versions based on the datasheet nomenclature. Availability of each combination should be confirmed with the manufacturer.

Manufacturer's example: SM303.10.2, 10 mm sensor, 4–20 mA scaling output and 0.5% linearity.

Another example of the order structure is SM301.10.2.T, with probe execution. For mechanical modifications and special versions, Schreiber can assign specific order codes.

The SM30 incorporates a threaded cylindrical housing M30×1.5 with tightening zones for SW27 wrench. The main body has a nominal length of 70 mm according to the drawing in the technical data sheet.

The standard version rod has a diameter of 16 mm in the area indicated on the drawing and an M4 threaded end. Dimensions should be checked against the drawing corresponding to the selected variant, especially when a probe or bellows is ordered.

The housing is made of nickel-plated brass; the stem is stainless steel and the core is a Ni-Fe alloy. The connector is nickel-plated brass and its contacts are gold-plated brass.

The threaded mounting allows for adjusting the sensor's position on the bracket. Lateral stress on the rod should be avoided.

The SM30 family offers optional mechanical configurations designed for different types of contact and protection:

• Version .T: probe execution for direct measurement of the displacement of a part using a measuring tip.
• Version .B: execution with protective bellows around the moving assembly.

The Schreiber drawing shows the probe construction with a reference length of 55 mm from the body and a maximum indicated dimension of 63.5 mm for the protruding assembly. These dimensions belong to the drawing of version .T and should not be confused with the nominal measuring stroke.

To select the mechanical execution it is necessary to define the stroke, the available space, the contact geometry and the environmental conditions of the installation.

The SM30 has a four-pin electrical connector. The pin assignment depends on the output model. The Schreiber datasheet shows the connection as seen from the sensor's own connector.

The SM305 and SM306 models require a symmetrical power supply. The remaining standard versions listed use a 20–32 VDC continuous power supply.

The data sheet also specifies protection against reverse polarity of the power supply.

Linearity classes: 0.5% and 0.25%, depending on the reference. The integrated electronics convert the core displacement into a proportional current or voltage signal.

The documented general values are:

• Measurement frequency: 800 Hz, according to Schreiber data sheet.
• Thermal drift: less than 0.01%/°C.
• Operating temperature: −20 to +85 °C.
• Vibration resistance: 20 g RMS, with peaks of 50 g.
• Shock resistance: 250 g SRS, 20–2000 Hz.
• Protection: IP66 with additional connector mounted; the technical header also identifies IP66/IP67.

The manufacturer's reference conditions are an ambient temperature of +20 °C, the nominal power supply indicated for the version, and a stabilization period of 10 minutes after connecting the sensor.

The measurement frequency of 800 Hz does not correspond to the maximum response frequency of the entire system. In dynamic applications, the acquisition and filtering conditions must be verified.

The SM301–SM304 current output versions support a load resistance of 0 to 500 Ω and have a specified maximum power consumption of 60 mA.

The documentation indicates a residual ripple of less than 0.005 mA peak-to-peak, as well as a load dependence of less than 0.001% for a change of 100 Ω and a power dependence of less than 0.05% for a change of 1 V.

The SM305–SM308 voltage output versions require a load of at least 2 kΩ and have a maximum rated current of 50 mA. Their residual ripple is less than 5 mV peak-to-peak.

For the SM307/SM308 versions, a maximum residual voltage of 0.1 VDC is indicated.

Applications of the SM30 as an LVDT displacement sensor with integrated analog output, without external conditioner:

• Stroke control of actuators and linear mechanisms.
• Position measurement in industrial machines.
• Monitoring the movement of moving parts.
• Measurement of displacements on test benches.
• Dimensional control with probe configurations.
• Integration of analog sensors into PLCs and acquisition systems.
• OEM equipment.

Other Schreiber series with integrated electronics: SM31 (programmable functions, similar threaded format), SM32 (square housing of 25×25 mm) and SM34 (miniature body of smaller diameter).

Selection criteria: travel distance, dimensions, output signal, power supply and installation requirements.

The SM303 and SM304 models provide 4–20 mA output. The SM303 has a rising signal and the SM304 a falling signal. Both require a 20–32 VDC power supply.

The SM307 and SM308 models offer 0–10 VDC output. The SM307 is step-up and the SM308 is step-down. The specified supply voltage is 20–32 VDC.

Yes. The SM305 and SM306 models provide ±10 VDC output and require a symmetrical ±13 to ±16 VDC power supply.

No. The measurement electronics are integrated and directly deliver the analog output of the chosen reference, with compatible power supply and acquisition input.

The manufacturer's technical data sheet documents nominal travels of 5, 10 and 15 mm, with linearity classes of 0.5% or 0.25% depending on the reference.

It is a Schreiber SM30 sensor with 4–20 mA scaling output, 10 mm nominal travel and 0.5 % linearity, according to the order example published by the manufacturer.

Yes. The documentation includes a .T version with a probe and a .B version with a bellows. Its configuration must be confirmed when defining the complete reference.

Guemisa supplies Schreiber Messtechnik sensors in Spain: models SM301 to SM308.