What do you do if the transmitter or control device in your process doesn’t have a display? Or maybe your transmitter has a display – 15 feet above your head. Will you bring a ladder every time you want to check your process data? Instead, you can just install a process display, also known as a loop-powered digital indicator wherever you need the information in the field. In the article here today,  we’ll look at a few process displays you can find on the market and what they offer. 

A process display gives you access to real-time process data any time you want and wherever you install it. It doesn’t need external power because it uses a current measuring loop. So let’s delve into some products on the market and their features.

The best loop-powered digital indicators

Many top vendors provide a range of loop-powered digital indicators to cover as many applications as possible, giving you a nice array to choose from.

Endress+Hauser RIA15

The RIA15 process display works on analog or HART signals. Its compact design fits nearly anywhere you need it, and you can read up to four values on it. You can get it with a panel-mount housing or field housing as a local display.

RIA15 Loop-powered indicator for 4...20 mA or HART®

Knick 830 series

Any process display from Knick’s 830 series will offer you a precise and accurate display of your process data. Its digital display has an integrated bar graph, and you can install it on equipment or control panels. You can also adjust its min/max outputs as well as zero/span.

Fluidwell F090

These general-purpose process displays have robust IP67 field enclosures, 5.5-digit displays, and pie graphs of ten segments. They also offer easy menus and multiple mounts for walls, pipes, and more.

Beka BA324E

BA324E is a 2-wire process display with 5 digit display. The key feature of this indicator is that it has Internal calibrator and the Robust GRP enclosure comes with a separate terminal compartment. Apart from all these, a membrane keypad enables indicator to be controlled without removing the cover.

PR Electronics Preview 5531

The Preview 5531 is a process display from PR electronics that can be easily scaled to display correct parameters. A Backlit Liquid Crystal Display is readable in low light conditions. And the front push-buttons can be disabled to stave off unauthorized adjustment.

Key specifications for loop-powered digital indicators

When you start shopping, you should keep these items in mind:

  • Good readability with a proper display also in dark surroundings (backlight). All characters should be perfectly visible.
  • Display ALL relevant information. HART is capable to deliver 4 values (e.g. temperature, level, pressure, PH)
  • Easy mounting and commissioning
  • Simple operation and easy parameter adjustment.


Device Endress+Hauser Knick Beka MTL/Fluidwell PR Electronics
RIA15 830 series BA324E 66x/F090 series Preview 5531
Communication 4…20mA and HART (up to 4 values) 4…20mA 4…20mA 4…20mA 4…20mA
Display 5 digits, 17 mm height 4 digits, 23 mm height 5 digits, 29 mm height 5.5 digits, 26 mm height 4 digits, 16 mm height
Bar graph
Voltage drop ≤ 1 V ≤ 0.5 V ≤ 1.2 V ≤ 1 V ≤ 1.5 V
(≤ 3.9 V with backlight) (≤ 5 V with backlight) (backlight powered separately) (≤ 10.5 V with backlight)
Dimensions 131 x 81.5 x 55.5 mm 175 x 80 x 57 mm 141 x 212 x 91 mm 130 x 120 x 75 mm 112 x 143 x 92 mm
Backlight (extra device)
Operation 3 keys 4 keys (inside housing) 4 keys (inside housing) 3 keys 3 keys
Protection class IP66 IP65 IP66 IP67 IP65


The above comparison table lets you select the right process display or loop-powered digital indicator depending on your requirements or applications. So, if you want compact loop powered Indicator incl HART communication and with a lower voltage drop, Endress+ Hauser’s RIA 15 fits for your requirement with worldwide approvals!

On the other hand, if your requirements are Zero/Span, Min/Max outputs adjustment capabilities, then Knick 830 series comes up to snuff. Also, you have Fluidwell F090 series that can fulfill the requirement of Pie Graph along with 5.5 digits to display.

Lastly, Beka BA324E is a good option when you need a Robust Indicator of GRP housing. However, PR electronics Preview 5531 provide reliable indications and provides the LCD Backlight intensity adjustment feature.

To know more about such indicators and their applications, you can always give us a call.

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