Solutions for safety loops.


Comprehensive asset management solutions reduce maintenance costs and increase the reliability of the function of field components. Transparent access to all data is only possible on the basis of cross-manufacturer standards, since plants rarely exist in which only one manufacturer’s field devices are used. Open standards such as HART, FF and Profibus are available. Safe versions such as FF SIS and Profisafe are soon to follow.

Contrary to end-users desire for more interoperability, some manufacturers "extend" these standards to include their own functions, these only being available if all of the automation components originate from that manufacturer. This means open standards revert to proprietary solutions after all, producing unilateral benefits for the manufacturer.

Because they support cross-manufacturer standards fully, HIMA systems enable the simple transmission of diagnostic and status data from any field device to any primary system - which is particularly attractive when it comes to field devices that are only connected up to the SIS.

HIMA has been the only manufacturer in the world to turn this into a solution to a safety problem. This is because the HART protocol enables the parameters of the field devices to be changed - such as measuring ranges and switching thresholds. If these values are safety-related, dangerous situations can arise.

HIMA solutions prevent this problem from arising. First details about this integrated solution can be obtained here.

A further aspect with regard to asset management is the so-called Partial Stroke Test. It can be used to demonstrate that a valve which is normally open or in its end-position is still able to move (corrosion can cause seizure).

This test can be treated (even if not as a 100% test) as an automatic diagnostic test belonging to the stipulated proof test interval, in which case it extends the phase of the actual proof test interval.The actual test procedure is carried out by means of adapted intelligent actuators, whereby a detailed diagnosis of the test is made possible using the HART protocol, for example. In addition, the safety system oversees that the test is carried out in a proper and regular manner from a safety aspect, and can pass this data on to higher-level systems as well.

Once again we see the benefits of safety systems that support internationally-accepted communication standards. This is because partial stroke tests can only be performed throughout a plant if all the valves, and all the safety systems that are connected up, speak the same language - such as the HART protocol.

Do you have a related question? Simply send an email to our DCS Competence Team. We will respond shortly.


Metso Automation

Partial stroke testing during operation with Neles ValvGuard and HIMA safety systems.