ABB argues that FDT/DTM and EDDL both have roles to play

A long-running spat over two technologies designed to improve interoperability between automation system components, appears to be coming to a head. The two technologies - FDT/DTM (Field Device Tool/ Device Type Manager) and EDDL (electronic device description language) - are both meant to provide standardised ways for defining the functions of process and automation equipment.

Most automation vendors support one system or the other, and a few support both. The main protagonists for EDDL are Emerson and Siemens. But support for FDT/DTM appears to be more widespread, and nearly 40 companies - including Rockwell, Schneider, Honeywell, Omron, Endress & Hauser and Yokogawa - have recently formed the FDT Group with the aim of making the FDT specification a global standard.

Last month, ABB, which supports both technologies, issued a statement criticising the mud-slinging between the two camps and arguing that both technologies have distinctive roles to play.

"Recently, there have been negative public statements about FDT/DTM technology," said Mark Taft, a senior vice-president for systems marketing with ABB. "The authors of these statements want their audience to believe that FDT/DTM and EDD are competing, mutually exclusive technologies - either you support EDD or you support FDT/DTM. This assertion is simply false."

ABB says that although it has participated in initiatives to enhance EDDL, working with bodies including the Fieldbus Foundation, Profibus International, and the OPC Foundation, the results still fall short of end-users` desire to integrate sophisticated device applications with automation systems.

For most field devices, it adds, EDDL can provide users with the same performance when they buy a device from one manufacturer and an automation system from another as buying a whole package from a single supplier. However, ABB feels that EDDL falls short for more sophisticated applications and does not address the integration of intelligent systems such as variable speed drives and smart motor controllers.

To integrate these more sophisticated applications, ABB is using FDT/DTM technology. It says that the FDT standard provides device suppliers with "a rich environment to develop and then integrate their applications" in automation environments that support DTMs.

According to Taft, ABB "will support both EDDL and FDT/DTM as complementary technologies in our process instrument, control system and power technology products". The company, he adds, "feels strongly" that exclusion of either technology would compromise the goal of ensuring that end-users are offered true interoperability between devices, systems and applications.