Thread break detector for sewing machines.

Eltex UPG-Stitch

The UPG-Stitch is a thread break detector designed to be used on sewing machines. It checks that the thread is moving in stitches. Both no thread movement and continuous thread movement will result in an active output. It operates on the piezoelectric principle, detecting the thread movement. This working principle makes it suitable for all types of threads and insensitive to dust, dirt, and humidity variations.

It has an optocoupler output suitable for PLC or other electronic control devices. A LED (light emitting diode) indicates the thread movement. The ceramic sensor part can be used either as a closed eyelet or as an open bar. Several sensors can also be connected in parallel. With its small size it does not require much space on the machine.


The sensor has a cable with a 6/4 modular plug connector. Several sensors can be connected in parallel. The sensor is protected against wrong polarity on power supply.

Technical Specifications

Housing in zinc metal
Power supply 15–30 V DC
Current consumption 20 mA
Max. switching current 10 mA
Max. voltage drop 2 V
Speed range 600 – 10 000 rpm
Cable length
 0.5 m
16760 3.5 m
Cable connector 6/4 modular plug connector

Function description

Sensing part Aluminium oxide ceramic, with a Ø3 mm closed eyelet and a 7 mm wide bar.
Output Optocoupler, active when the thread is not moving correctly.
Sensitivity setting The sensitivity can be adjusted with a potentiometer under the lid.
The output reflects the movement of the thread. When the thread is moving correctly, the optocoupler is inactive. When the thread is not moving or moving continuously the optocoupler is active.
The LED is on when the thread is moving correctly. It is flashing steady when the thread is not moving. It is flashing irregularly when the thread is moving continuously.

Dimensions (mm)

UPG drawing of dimensions

Thread direction possibilties

UPG Thread direction possibilities

KG Lundholm

Can I help you?

Do you have a specific request or would like to know more about our sensors and the sureveil-lance system please contact me and I will sort everything out