You can find hazardous conditions, known as Ex areas, in many segments,  and all devices installed in these areas require great care in their connections to the control system. The Weidmuller ACT20X-HDI-SDO-RNO-S, today’s device, is ideally suited to these conditions.

Some zone classifications have more requirements than others. We talked about the classifications in an earlier Q&A, if you want to read it.

When you have a Zone 0 or 1, a field device must use an intrinsically safe signal. You can find intrinsically safe solutions on the market that can connect, isolate, and convert signals from devices in Ex zones to safe areas.

The Weidmuller ACT20X-HDI-SDO-RNO-S

Today, let’s have a look at one solution from Weidmuller, the ACT20X-HDI-SDO-RNO-S. You can find this device in our shop. The ACT20X is an isolator or converter that can connect to NAMUR sensors and contact or resistance signals in Zones 0 or 1 to safe areas.


Single channel digital signal converter/isolator

From €112.59

It offers a transistor or relay output to integrate into the control system. (If you need a dual-channel version, then Weidmuller offers that as an option too.)

This straightforward product makes an application safe in an Ex area. You can install the ACT20X on a TS 35 DIN rail. It follows the industry standards, so you won’t have any trouble applying it in your new installation.

What can the Weidmuller ACT20X-HDI-SDO-RNO-S do?

Let’s suppose you have intrinsically safe devices in a Zone 0 area, and you need to connect them into the control system. In this scenario, you only need an on/off indication, such as high and low or open and close.

The ACT20X can act as the bridge to connect a sensor in Zone 0 to the control system in Zone 2. Additionally, you can have some configuration options via FDT/DTM, using the free software WI-Manager from Weidmuller and a USB adapter.

It has direct or inverted action for each channel, and on top of that, you can check its self-diagnostics. It constantly monitors for error events, cable breakage, and more.

Locally, you have an LED indicator that can clue you in to the status of the device. Finally, it has 3-way galvanic isolation applied between the input, output, and supply.

When do I need the Weidmuller ACT20X-HDI-SDO-RNO-S

If you need to integrate a field device with NAMUR output or contact or resistance signals into the control system, then the ACT20X as a pulse isolator can transmit these signals to the control system using its transistor or relay output.

Weidmuller ACT20X-HDI-SDO-RNO-S Technical Details

  • Dimensions:  22.5 mm width, 117.2 mm height, 113.6 mm depth
  • Net weight: 177 g
  • Operation temperature: -20 to 60°C
  • SIL in compliance with IEC 61508: 2
  • Voltage supply: 19.2 to 31.2 VDC
  • Configuration: FDT/DTM software
  • Input: NAMUR sensor (EN 60947), 8 VDC/8 mA power supply, 0-5 kHz input frequency, and wire-break detection
  • Output: status relay, relay output,  transistor NPN output


If you need an intrinsically safe solution, the Weidmuller ACT20X-HDI-SDO-RNO-S is a good option. You can see all the technical information on the device page in our shop.

To know more about such isolators and convertors, you can get in touch with our engineers!

Recommended articles

Product Review: Weidmuller ACT20-FEED-IN-BASIC-S

Articles Product Review Signal Converters and Isolators