The way forward for HART users.
HART communication has been around since the early 1980’s. Its vast presence in the process installations shows that the technology is still fulfilling the need of most applications and requirements of their users. Because of its wide spread over all sorts of industries it feels odd to leave this technology behind, especially for those who have been working with it for so long. Let’s see how disclosure of the field instrumentation can work for us in various situations.
If you are starting from scratch it is easy to implement new technology. Training for the maintenance department is absolutely required from the beginning, as is their involvement in the commissioning to make this successful.
If control systems are replaced then another opportunity presents itself namely, adding new technology whilst existing field instrument remains in place. By adding e.g. remote IO systems one can benefit from the features of fieldbus technology, but also build on the familiarity with the existing HART communication.
On top of that manufacturers provide converters for HART instrumentation to be connected to PROFIBUS DP as well as PROFIBUS PA directly, allowing to multidrop HART instruments from 4 to 15 instruments per channel depending on the application.
When starting up the first thing we would like to see is whether all instruments are properly connected to the system. With fieldbus we know where we stand by generating a ‘Live list’ of the installation. At a glance one can see what is failing and fix right away before proceeding. Once everything is ‘Live’, setting parameters or adjusting the configuration is easily done from behind your computer, instead of going into the field every time. Even HART communication can run over the fieldbus cables via our remote I/O system or HART/PROFIBUS converter.
How much time is spent traveling the plant from the control room or workshop to the field to investigate an alleged problem with an instrument depends on how big the plant is. It is difficult to generalize the costs involved for maintenance, but there is a difference between going into the field with your handheld and your tool bag, cycling for 10 min, climbing to the 3rd floor on a rainy afternoon, or investigating the problem via your Maintenance station located in e.g. the Control Room, while sipping coffee.
In short, whatever you are planning there will always be a time to think of HART communication in combination with PROFIBUS DP or PA. How this will suit your interest best depends on the time spend investigating the possibilities. There is no need to leave old technology behind and just focus on new ones. The outlook is without a doubt Industry 4.0 and/or Industrial Internet of Things, but we should not waste our legacy.