Scales for Ex Areas

Scales for Ex areas from RADWAG are scales and weighing devices developed in accordance with the ATEX directive for use in potentially explosive atmospheres. Depending on the version, they work in areas with explosive gases (zones 1 and 2) or gases and dusts (zones 1/21 and 2/22). The range includes HX5.EX platform, pallet, beam and ramp scales with a capacity of 1.5 kg to 6000 kg, HRP EX high-resolution platforms with a readability from 0.02 g, the PUE HX5.EX weighing terminal, PM01.EX and PM02.EX intrinsically safe power supplies and IM01.EX communication modules. Ex scales belong to the RADWAG industrial scales range and are designed and manufactured in Poland.

Hazardous areas – which scale to choose?

Potentially explosive areas are divided into zones according to the type of substance and how often an explosive atmosphere occurs. For gases, vapours and mists these are zones 0, 1 and 2; for combustible dusts – zones 20, 21 and 22. In zone 1/21 an explosive atmosphere is likely to occur during normal operation, and in zone 2/22 only rarely and for a short time. Zones are classified by the plant operator and recorded in the explosion protection document. The scale is chosen to match this classification:

• HX5.EX scales for areas endangered with gas explosion – zones 1 and 2,
• HX5.EX scales for areas endangered with gas and dust explosion – zones 1/21 and 2/22, stainless steel versions,
• HRP EX platforms – zone 2 or zones 2 and 22, depending on the design.

RADWAG scales and devices for Ex areas

How is an Ex weighing system built?

A scale for an Ex area is a set of devices, each certified for use in an explosive atmosphere. Safety is ensured by intrinsic safety: the energy in the electrical circuits is limited so that it cannot ignite an explosive mixture.

• Weighing platform – HX5.EX with one or four strain gauge load cells, or an HRP EX high-resolution platform connected to the terminal via an intrinsically safe RS485 interface.
• PUE HX5.EX weighing terminal – indicator for zones 1/21 and 2/22, with two intrinsically safe RS232 interfaces and one RS485.
• Intrinsically safe power supply – the PUE HX5.EX terminal is powered only by certified RADWAG power supplies. PM01.EX-1 is installed in the hazardous area (zones 1 and 2, explosion groups IIC, IIB, IIA, temperature classes T1–T4), while PM01.EX-2 is installed outside it – only its intrinsically safe circuits are routed into the zone. HRP EX platforms are powered by PM02.EX-1-2 and PM02.EX-2-2.
• IM01.EX communication module – installed outside the hazardous area and connected to the terminal via an intrinsically safe RS485 interface. It adds Ethernet, USB, 4–20 mA / 0–10 V analogue outputs, Profibus DP and additional digital inputs/outputs, so the scale can work with printers, scanners, PLCs and host systems.

PUE HX5.EX terminal

• 5″ colour graphic display protected by impact-resistant polycarbonate and a membrane keypad,
• AISI 304 stainless steel housing with IP66/IP68 protection (immersion up to 1.5 m),
• weighing, parts counting, dosing and checkweighing functions,
• databases of users, products, weighings, tares, formulations and customers, plus ALIBI memory,
• user interface configurable with widgets,
• works with accessories inside and outside the hazardous area: barcode scanners, printers, additional displays, control buttons and signal towers.

The terminal is part of the RADWAG weighing terminals family.

Applications of Ex scales

• chemical and petrochemical industry – weighing raw materials, solvents and products in gas hazardous areas,
• paints, coatings and adhesives – dosing ingredients and solvent-based formulations,
• pharmaceutical and cosmetics industry – processes involving alcohols and solvents,
• food and feed industry – rooms with combustible dusts such as flour, sugar or starch,
• plastics and powders – weighing granulates and dusty substances,
• warehouses and filling stations for flammable substances – weighing drums, containers and pallets.

How to choose a scale for an Ex area?

• Type of atmosphere – gases and vapours only: scales for gas hazardous areas; gases and combustible dusts: scales for gas and dust hazardous areas (stainless steel versions).
• Zone – HX5.EX scales work in zones 1 and 2 or 1/21 and 2/22, HRP EX platforms in zone 2 or zones 2 and 22.
• Load and capacity – single load cell scale up to 300 kg, four load cell scale up to 6000 kg, pallet or beam scale for pallets, ramp scale for trolleys and drums.
• Accuracy – if you need a readability from 0.02 g, choose an HRP EX platform with internal adjustment.
• Material – powder-coated steel for typical production halls, AISI 304 stainless steel where corrosion resistance and washing are required.
• Power supply – power supply in the zone (PM01.EX-1) or outside the zone (PM01.EX-2), depending on where mains power is available.
• Communication – to connect the scale to a computer, PLC or plant network, add the IM01.EX module.

FAQ – scales for Ex areas

What does ATEX mean?

ATEX (from the French Atmosphères Explosibles) is the European Union directive 2014/34/EU that sets the essential requirements for equipment intended for use in potentially explosive atmospheres. The scales, terminals, power supplies and modules in this category are developed in accordance with this directive, and declarations of conformity and certificates are available on the product pages.

In which zones can RADWAG Ex scales be used?

HX5.EX scales work in gas hazardous zones 1 and 2 or – in the gas and dust versions – in zones 1/21 and 2/22. HRP EX platforms work in zone 2 or in zones 2 and 22, depending on the design. The PUE HX5.EX terminal is intended for zones 1/21 and 2/22.

What is the difference between the PM01.EX-1 and PM01.EX-2 power supplies?

PM01.EX-1 is installed in the hazardous area (zones 1 and 2, groups IIC, IIB, IIA, temperature classes T1–T4). PM01.EX-2 is installed outside the hazardous area, and only its intrinsically safe circuits are routed into the zone. The choice depends on where 100–240 V AC mains power is available.

Can an Ex scale be connected to a computer or PLC?

Yes. The PUE HX5.EX terminal has two intrinsically safe RS232 interfaces and one RS485. The IM01.EX communication module, installed outside the hazardous area, adds Ethernet, USB, 4–20 mA / 0–10 V analogue outputs, Profibus DP and additional digital inputs/outputs.

What is the protection rating of the PUE HX5.EX terminal?

The terminal housing is made of AISI 304 stainless steel and is rated IP66/IP68 (immersion up to 1.5 m). The display is protected by impact-resistant polycarbonate.

Is high-accuracy weighing possible in an Ex area?

Yes. HRP EX high-resolution platforms offer a readability from 0.02 g with capacities from 10 kg and internal adjustment, which ensures repeatable results in harsh industrial conditions.

Looking for a scale for a hazardous area? Contact our specialists – we will help you choose the scale, power supply and communication module to match your zone classification, and provide technical support.