Christos Papakyriacou, Managing Director at Alpha Micro Components & Gordon Lunn, Global Customer Engineering Support Manager, FTDI Chip explores how automation is driving HMI deployment

Human Machine Interfaces (HMIs) play a significant role in industrial automation, enabling the efficient operation and monitoring of essential production equipment. According to a report from Research and Markets “Human Machine Interface Market, Global Forecast & Analysis (2012-2017) growth in the automation industries is a major driver of HMI deployment.

The other key factors driving the market include demand for enhanced efficiency, high growth of software services suitable for each application and increasing need for data security and reliable hardware. On the other side, the HMI market growth is hampered by factors like limited geographical diversity, high cost of HMI platforms and advancements in technology at a relatively slow pace.”

Designing HMI?Touch screens

Designing HMIs such as industrial touch screens has however now been made significantly easier with the availability, via Alpha Micro of FTDI Chip’s, development modules designed for use with the company’s FT800 EVE embedded video engine.

EVE has had a significant impact on the way that engineers can create HMIs on QVGA and WQVGA based TFT displays. Due to this latest methodology, it allows more advanced HMIs to be realised across a broad spectrum of application areas.

While conventional intelligent display systems require separate graphic control, touch control and audio functions, EVE integrates all these onto a single chip.

The need for a high performance microcontroller unit (MCU) to create and manipulate the graphic images (which is typically achieved in a pixel-by-pixel fashion) is also negated, as it can be replaced by a lower performance device.

Conventional intelligent display systems require separate graphic control, touch control and audio functions, EVE integrates all these onto a single chip….

It also means that a large Flash memory is no longer needed for storing the graphics library, nor is a frame buffer to drive the display. This equates to a sizeable reduction in the overall bill of materials, as well as substantially less board space being taken up.

The EVE permits a more streamlined implementation to be realised. The FT800 has a built-in 4-wire touch controller and a single channel audio controller which allows various chirps, beeps, taps, and midi-like sounds to be assigned/tagged to specific areas of the display. It uses a less complex object-oriented approach, where objects can be user defined images, fonts, widgets, primitives, c sounds, bitmaps, etc. By enabling the design to work at a higher level of abstraction/description the display can be created faster resulting in reduced development time and cost. The display output quality is maintained as images are rendered to at 1/16th pixel resolution. The IC’s memory consists of a small ROM memory for sounds and fonts and an embedded 256kByte RAM which is utilised for users’ images as well as execution of display list commands.

The display is rendered by a 2kByte buffer, with 16 outputs, formatted for RGB input displays. As the FT800 performs the bulk of the graphics, touch, and audio operations, low bandwidth SPI or I2C inputs can be employed to communicate display list commands between the system host and the IC. This is in contrast to conventional display/HMI architectures that use wide data buses between controllers, and that result in higher pin-count devices, as well as increased board area and IO power consumption.

This device is integrated into a series of new development boards to for improving HMIs.  

A 4-wire resistive touch screen is integrated onto the specified LCD for each of these modules. The modules also support mono audio output with an on-board audio power amplifier and a micro speaker both included on each unit. They can be powered at 3.3V or 5V through either a 2.1mm power jack, a SPI master connector or via its USB Micro-B port. The modules have a standard SPI interface so that any microcontroller with this commonly used IO can be easily connected with EVE technology. 

In conclusion technological advancement and a significant increase in factory automation has created a strong demand for HMIs – it’s as a result a major growth area that needs to be addressed with a new breed of products.

Alpha Micro Components

01256 851770