As engineers and technicians upgrade their plant and machinery, they are finding out that many field devices are not equipped with a fieldbus connection. They are faced with waiting for such a device to be developed, or looking for a way to continue using a trusted device already in service at their facility. Many of the new production modules and process skids are supplied with Profibus-DP or Profibus-PA device networks. In many cases, their existing application already has a 4-20 mA field device that is also HART-capable, but customers are not able to find a similar device with Profibus connectivity from the original supplier. Or for that matter, anywhere else in the market place. The same is true for a Modbus RTU device with a serial RS-485 connection. “It would be great to continue using this device in my upgrade”. So how do they connect HART or MODBUS RTU devices in a Profibus network?
Phoenix Contact recently introduced a pair of HART, and a pair of MODBUS/RTU Protocol Converters that allow field devices to be integrated into Profibus-DP or Profibus-PA networks. These protocol converters allows easy configuration using a Device Type Manager (DTM) in a FDT/FRAME communication interface. The Device Type Manager contains all of the relevant configuration data and parameters needed to quickly connect the field device to a Profibus network. The DTM is used to set-up, configure, monitor and diagnose device behavior.
Even simple analog and digital I/O signals are as important as a smarter field device. Phoenix Contact was approached by a global continuous process customer in 2017 with the need for I/O to be connected into their Profibus-PA network. The control and instrumentation engineers wanted to connect the I/O using their existing Profibus-PA cables – each I/O signal would have required a wire pair all the way from the field back to the control room. This cable installation would have been expensive and time consuming – requiring a plant shutdown and resulting in loss of production revenue. The installers needed to deploy the systems as quickly as possible. In addition, the installation required the monitoring of certain specialized digital inputs (Namur or supervised inputs), as well as relay outputs to drive larger loads in the field. The provided solution was a combination of a modular head station that had a Profibus-PA address and I/O expansion modules that are available for Digital I/O, Analog I/O and Relay outputs. Once assembled and powered on the DIN-rail, the integration occurred easily via the Device Type Manager and FDT-enabled system. One benefit of the DTM is that the installation was commissioned easily and quickly on a weekend, allowing the plant to be back in operation the week thereafter. Products that can be commissioned using a DTM offer a competitive advantage due to the ease and speed of integration.
For more information on the Protocol Converter visit the Phoenix Contact website at www.phoenixcontact.com and enter the webcode “#1793” for more product information. The Profibus PA I/O Gateway can be found using the webcode “#1792”.
Article contributed by Phoenix Contact