Senmatic's EC & pH alarm EPA904

EPA904 EC and pH Alarm

External alarm detecting and responding to mechanical and human errors

This standalone EC and pH alarm unit measures EC and pH and emits an alarm when the set limits are exceeded. Multiple uses include using the alarm in e.g. an irrigation system. Four separate alarms can be set for minimum and maximum EC and minimum and maximum pH alarm respectively.

Extra security
Used together with a fertilizer mixer, you have additional security with this standalone EC and pH alarm. EC and pH will now be measured not only by the electrodes from the mixer, but also by the alarm.

Readout on scale
Quickly read the actual EC and pH level in the irrigation water directly from the scale on the box.

Easy to set
Setting the alarm levels is done easily using the buttons on the front of the box. Whenever an alarm occurs, a diode for the actual alarm will light up next to the knob with the setting.

What's in it for you? - see more

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What's in it for you?

  • Alarm unit for measuring EC and pH values in irrigation systems

  • Alarm at exceeded maximum and minimum values of EC and pH

  • Readings on a scale directly from the unit

  • Four separate alarms

  • Ensures extra security

  • Easy to setup

Download product sheet Technical specifications
Download product sheet

Download product sheet

Technical specifications



  • Supply: 24 VAC ±10 % 50/60 Hz - 400 mA
  • Alarm output: Potential free contacts max. 42 V - 2 A
  • Output EC: 0.3 - 4.5 V = 0 - 14 mS
  • Output pH: 0.3 - 4.5 V = 0 - 14 pH
  • Input EC: 2 point / 4 point EC electrode
  • Input pH: Standard pH electrode


  • Temperature: 0 - 50° C (32 - 122° F) without direct radiation
  • Humidity: 0 - 95 % RH without condensation
  • Dimensions H x W x D: 200 x 300 x 100 mm (7.8 x 11.8 x 3.9")
  • Weight: 2 kg (4 lb)
  • Protection: IP54
  • Emission: EN50081-1
  • Immunity: EN50082-1


  • EC sensor: Type ECE 89 or ECE 99
  • pH sensor: Type pH 2000
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