Sewing machine model, RS422 interfaced

ETM RS422 interfaced

The Eltex Tension Monitor (ETM) is an on-line device for sewing machines and similar applications. The device monitors the thread tension and also acts as a thread break detector. It enables the operator to keep the thread tension within the desired tension range for best operation and quality of the seam.

The ETM 422 is designed for OEM customers. It is communicating through an RS422 interface with the host computer on the machine. The host computer must have the firmware for the RS422 communication. Eltex is providing the protocol for this communication.

Eltex offer an accredited calibration of this unit.
The calibration method we use has been approved according to the Standard ISO/IEC 17025.


Typical Application


  • Monitors thread tension according to limits set by the software through RS422 interface.
  • Programmable measuring ranges.
  • Programmable RS422 message with peak tension and monitor status for every stitch.
  • Programmable stop filter function.
  • Generates stop pulse when thread tension is outside the selected Stop Limits.
  • Separate sensor head and electronics enables fitting in tight areas.
  • LED indication of monitored limits and synchronization input.
  • Alarm message possible through RS422 line and separate optocoupler output.
  • Factory calibrated – no manual reset.
  • ESD protected inputs and outputs (optocoupler).

  Leaflets & info


Technical Features

  • Measuring range adjusted within: 0–1200cN
  • Available measuring ranges:
    0–128cN, 0–256cN, 0–384cN, 0–512cN, 0–640cN, 0–768cN, 0–896cN,
    0–1024cN, 0–1152cN, 0–1280cN, (0–1408cN, 0–1536cN)
  • Stop filter: 1–15 stitches
  • RS422 parameters: 9600 baud, 1 start bit, 8 data bits, 1 stop bit, 1 parity bit, even parity
  • Supply voltage 10–38 V DC
  • Maximum current consumption 50 mA
  • Maximum start peak current 500 mA (*Note 1)
  • Speed range 120–10 000 RPM
  • Message alert pulse length Minimum 2 seconds
  • Cable length between sensor head end electronics box 100 mm (50–500 mm on request)
  • Electronic box dimensions 100 x 61 x 25 mm (width x height x depth)
  • Sensor head dimensions 25 x 42 x 29 mm (width x height x depth)
  • Message alert output Optocoupler TLP127, max. 100 mA
  • Synchronisation input Optocoupler TLP112, Rin 1.5 kΩ, Vin 5–35 Vdc
  • Working ambient temperature range 15–45°C (60–110°F)
  • Working ambient humidity range 0–95% RH (at 45°C) no condensation
    *Note 1: At supply voltage 38 Vdc and power supply start-up time = 30 ms.


  •  Improves sewing quality.
  • Allows you to operate with the correct thread tension.
  • Acts as a thread stop motion / thread break detector.
  • Protects against overtension.
  • Alerts the operator to dirt and dust in the thread tensioners.
  • Makes it easier for the operator to set the correct bobbin tension.

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