Temperature controller users demand more comms

Edited by the Engineeringtalk editorial team Apr 19, 2006

Specifiers and purchasers microprocessor-based single loop industrial temperature controllers expect to have increasing need for communication bus/network capabilities.

A recent market study by Venture Development Corporation (VDC) finds that specifiers and purchasers microprocessor-based single loop industrial temperature controllers (MP-SLs) expect to have increasing need for communication bus/network capabilities in these products.

During this study, VDC conducted telephone interviews and a detailed e-mail survey with users of these products to ascertain their current and future requirements.

Among these were their needs for communication bus/network connectivity.

The majority of units purchased in 2005 had communication bus/network connectivity, with a further significant share increase expected by 2010.

Having bus/network connectivity is becoming very important as applications become more complex linking more processes together.

Communication bus/network interface capabilities can be provided in the controllers to allow communication with the controller from a remote location.

Use of such networking may include: digital input of sensor signals; remote programming; transmittal of control parameter settings for monitoring; transmittal of diagnostic and alarm information; transmittal of digital control signals; and transmittal of temperature measurement data for monitoring and other purposes.

Users were asked what types of digital communication interfaces were provided on the industrial MP-SL controllers they purchased in 2005, and which they expect in 5 years.

Ethernet was the most popular, and is expected to have the largest increase in share among these users through 2010.

Ethernet is inexpensive, mature, highly reliable, and a proven system.

The data from the user survey is not encouraging that a limited set of Ethernet protocols will gain favour.

It was found among those using Ethernet, that by far the largest share is using the Ethernet/IP application layer protocol.

However, the percentage using this protocol is expected to decline.

The Modbus TCP application layer protocol was found to be the second most popular among the survey respondents.

Only a 2% gain is expected in the share of the Ethernet respondents using this protocol with MP-SL controllers.

Among other Ethernet application layer protocols, the most popular with these users are Profinet and HSE.

A slight decline in Profinet popularity is expected.

However, an increase in popularity is expected for HSE.

HSE is the Foundation fieldbus high speed backbone network designed for linking controllers in process industry applications.

Is this proliferation of application layer protocols usage desirable for industrial automation?.

Certainly, it does not lead to broad-based interoperability of products from many different vendors.

Will one or a few ever become defacto standards?.

If so, which ones?.

The answers are unclear at this time, and it is likely that Ethernet will continue its migration to the plant-floor in many guises, and broad-based interoperability will remain a gleam in users' eyes for many more years.