Gone are the days you could get away with a set of buttons and maybe an LED or two for the control interface of an industrial automation control unit. Today’s industrial designs demand operational functionality more like the intuitive smartphone user interface we are all now familiar with. Making the control of fairly complex processes and/or automation equipment straightforward for the user has meant that developers need to pay a lot more attention to building such capabilities into their design. Also, establishing a platform-based approach to the control processor board allows manufacturers to amortise the initial design costs across a range of different product variants in addition to keeping on-going support costs, training and revision complexities to a minimum.

Using this approach, a range of controllers can quickly be brought into the market with analogue and I/O flexibility provided by modular daughter boards to suit differing control needs. In order to accommodate different interface complexities and screen size requirements this platform approach can also be used. An example of this is the range of TFT displays available from Riverdi. Based around the FT8xx EVE controller ICs from FTDI, the range includes 2.8”, 3.5”, 4.3”, 5” and 7” displays available with or without touchscreens (capacitive or resistive). The key aspect of using these displays is that the control interface is the same whatever the screen size, further keeping variant and support costs constrained yet offering product development flexibility.  When selecting a display platform to incorporate in a design, the embedded developer also has a number of other product considerations. One of these relates to the availability of suitable development tools, drivers and reference designs in order that the design-in of the display is as straightforward as possible. The Riverdi range provides an evaluation board that is designed specifically for use with the FT8xx-based TFT displays. Not only does this evaluation board provide the hardware environment on which to test your design, it is also complemented with a broad range of software support tools from FTDI that include the standard demo firmware, source code and a comprehensive application note that explains the display initialisation process, line and bit map graphic drawing and using an on-screen software keyboard routine for data entry.

When looking to incorporate a display into any industrial automation controller design, one of the key usability factors will be the viewing angle. As I’m sure we have all experienced in the past, viewing a display from the wrong angle can result in grey scale inversion and poor contrast. When it comes to placing a controller in a position that is not only convenient for the machine operator but allows full visibility of the machine’s operation may result in trade-offs that result in poor screen usability.

Riverdi’s displays are differentiated from others on the market by their approach to improving the viewing angles with the addition of an ‘O’ film to the glass screen. Providing screen viewing angle improvements in line with other techniques such as in-plane switching (IPS) and multi-domain vertical alignment (MVA) but at a fraction of the cost, the Riverdi approach facilities a viewing angle range of 80 degrees in all directions.

By equipping developers with a range of well-supported and documented TFT display modules ensures that engineers can quickly introduce new product families to market without having to worry about each having their own support complexities.