turck Articles

DieGuard Protection Sensors

TURCK 7/23/2018


Protect Your Die Investment with Rugged TURCK Sensors

With all the time and money spent on your dies, protecting them with affordable, easy-to-apply TURCK DieGuard sensors is a smart investment. From our miniature 4 mm diameter barrel sensors, to our ultra-narrow Q-Pak Series, rugged TURCK sensors are designed for feed, slug, stripper plate and part-out detection applications–preventing double hits and crashes.

DieGuard Protection Sensors

TURCK sensors can be embedded in dies or positioned around them in the tightest spaces. Able to withstand severe shock and vibration, fully-encapsulated TURCK sensors are sealed against harsh liquids and the sensing field is completely immune to oil.

Metal Forming Sensors

Common Applications

• Inductive proximinity sensor used for strip feed
• Inductive proximity sensor used for strip feed, N.O. switch
• Material feed monitoring
• Ring type inductive proximity sensor used for part out detection

Embeddable (Shielded) vs. Nonembeddable (Nonshielded)

DieGuard Protection Sensors

Embeddable construction includes a metal band that surrounds the ferrite core and coil arrangement. This helps to “bundle” or direct the electromagnetic field to the front of the sensor.

DieGuard Protection Sensors
Nonembeddable sensors do not have a metal band; therefore, they have a longer operating distance and are side sensitive.

Differential Travel (Hysteresis)

DieGuard Protection Sensors

The difference between the “operate” and “release” points is called differential travel (see shaded area in Figure 3). It is factory set at less than 15% of the effective operating distance. Differential travel is needed to keep proximity sensors from “chattering” when subjected to shock and vibration, slow moving targets, or minor disturbances such as electrical noise and temperature drift.

Actuation Mode

Inductive sensors can be actuated in an axial or lateral approach (see Figure 3). It is important to maintain an air gap between the target and the sensing face to prevent physically damaging the sensors.

Uprox Characteristics

• No Correction Factor - Same rated operating distance for all metals.
• Extended Operating Distance - Up to 400% greater than standard inductive sensors when using non-ferrous targets (Figure 4).
• Weld Field Immunity - Uprox is unaffected by strong electromagnetic AC or DC fields because of its unique patented design.
• High Switching Frequencies - Up to 10 times faster than standard inductive sensors.
• Extended Temperature Range - Uprox can withstand temperatures up to 85°C (+185°F) with a ±15% temperature drift.

DieGuard Protection Sensors

Operating Principle Uprox

TURCK Uprox is a patented next generation development of inductive sensors that uses a three-coil system. One coil induces eddy currents on the metal target and the other two coils are affected by these eddy currents. Ferrous and nonferrous metals have the same effect on the two coils. Therefore, all metals, including galvanized metals, have the same rated operating distance.

TURCK standard inductive sensors use a single coil randomly wound around a ferrite core. The single coil both induces eddy currents on the metal target and is affected by these eddy currents. Ferrous and nonferrous metals affect the sensor differently, making it impossible to detect both types of metals at the same rated operating distance.

DieGuard Protection Sensors
Operating distances comparison of Uprox sensors and standard inductive sensors.

Operating Distance (Sensing Range) Considerations

The operating distance (S) of the different models is basically a function of the diameter of the sensing coil. Maximum operating distance is achieved with the use of a standard or larger target. Rated operating distance (Sn) for each model is given in the manual. When using a proximity sensor the target should be within the assured range (Sa).

Standard Target

A square piece of mild steel having a thickness of 1 mm (0.04 in) is used as a standard target to determine the following operating tolerances. The length and width of the square is equal to either the diameter of the circle inscribed on the active surface of the sensing face or three times the rated operating distance Sn, whichever is greater.

Operating Distance = S

The operating distance is the distance at which the target approaching the sensing face along the reference axis causes the output signal to change.

Rated Operating Distance = Sn

The rated operating distance is a conventional quantity used to designate the nominal operating distance. It does not take into account either manufacturing tolerances or variations due to external conditions such as voltage and temperature.

Effective Operating Distance = Sr 0.9 Sn ≤ Sr ≤ 1.1 Sn

The effective operating distance is the operating distance of an individual proximity sensor at a constant rated voltage and 23°C (73°F). It allows for manufacturing tolerances.

Usable Operating Distance = Su 0.81 Sn ≤ Su ≤ 1.21 Sn

The usable operating distance is the operating distance of an individual proximity sensor measured over the operating temperature range at 85% to 110% of its rated voltage. It allows for external conditions and for manufacturing tolerances.

Assured Operating Range = Sa 0 ≤ Sa ≤ 0.81 Sn

The assured actuating range is between 0 and 81% of the rated operating distance. It is the range within which the correct operation of the proximity sensor under specified voltage and temperature ranges is assured.

DieGuard Protection Sensors