In Detail
For no less than 30 days the safety relay successfully withstood flowing corrosive gases in the Weidmüller laboratory. This successful outcome is due to additional protective measures for the electronics – clear added value for applications such as offshore or chemical facilities.
ffshore facilities such as wind generators or oil platforms are constantly doused with salt spray. Certain chemical facilities are exposed to traces of chlorine or hydrogen sulphide in the ambient air.
Atmospheres of this kind are toxic for metallic materials, as they cause corrosive damage, thus leading to premature wear of installed equipment.
This phenomenon is by no means restricted to exposed components. Even the control cabinet is not able, in all cases, to protect components from ➜
1. Reliably shutting down during an emergency
2. Safe application in corrosive atmospheres
3. Furnace control in thermo-process facilities

In Detail
external influences. If no additional protective measures are employed, such as positive pressure ventilation of the control cabinet, then contaminated air can penetrate the cabinet, bearing corrosive agents such as acids, salt or moisture.
Fit for corrosive atmospheres
"Especially in safety systems, any reduction in the availability of the installed systems due to corrosion is a serious danger. In the worst case, the required safety integrity level (SIL) is at some point no longer available," says Joachim Janik, product manager at Weidmüller. "To reduce this risk for our customers, we have not only made our safety relays of the SAFESERIES fit for safe use in corrosive atmospheres
– we have also thoroughly tested the effectiveness of our protective measures before application in the field."
The Weidmüller experts apply a protective coat to reliably shield the electronics inside the safety relay.
The protective coating is applied in a special spray process. "If we apply too much coating it does not become hard enough. Too little coating and the required degree of protection is not achieved," says Janik describing the special challenges. "The tests in our laboratory confirm that we are obtaining optimum protection with our process."
Application in G3 environment possible
The Weidmüller laboratory continuously exposed the safety relay to corrosive gases for an entire month.
A mixed gas test was performed based on the standard EN 60068-
2-60 – known as the 4-component corrosive gas test. The corrosive gas concentration was adjusted to the
ISA level (Instrumentation Society of
America ISA S71.04-1985), G3 and was thus significantly higher than the standard actually required for the
4-component corrosive gas test.
In this way it was possible to very accurately replicate the ambient conditions encountered in practice. "To make doubly sure, we have exceeded the highest duration specified in the standard with a test duration of 30 days," says the head of the
Weidmüller electronics laboratory,
Wolfgang Nietzsch. "The safety relay was in operation for the entire period.
We were able to verify by means of functional tests that the protective coating on the PCB reliably resisted the corrosive gases. At no stage did we note any impairment of the function."
On completion of the corrosive gas test, subsequent microscopic examinations showed that the safety relay was still in a perfect condition: in spite of the punishing test conditions, the corrosive gases had not attacked the material.
"We know that it is increasingly important for our customer to be able deploy SIL products even in corrosive environments, which are classified as Level G3," says Janik, summing up current practical requirements. "With our successful corrosive gas test, we show that our safety relay is absolutely suited for exactly such applications.
We have confirmed this in our manufacturer declaration."

In Detail
Thomas Peter, Electronics Portfolio
Manager, on the trend towards urbanisation and on maintaining operational safety
WIN!
From your point of view, which global trends are most influential in shaping Weidmüller's range of electronic products?
Peter: The megatrends which influence us are very obviously urbanisation and the associated challenges in the area of energy production. The "flight from the countryside" is driving the dynamic growth of cities, which are becoming conglomerations. In building up and expanding energy supply facilities near such mega-cities, the decisive factors are reliability of supply and operation.
WIN!
How can you help your customers to achieve greater operational safety?
Peter: Although individual components may achieve the desired reliability, simply hooking up a series of electronic components is by no means enough to create an efficient, reliable overall solution. It is more important to have mutually compatible components, which when combined, create a solution for the specific application. An example of an application required by our customers is the overflow protection in oil tanks. In combination with the SIL 3 certified surge protection VARITECTOR SPC, our safety relay creates a safety circuit in compliance with the SIL 3 safety level. This ensures that, in the event of plant faults, man, machine and environment are all protected from the serious consequences.
WIN!
Is Weidmüller prepared for the growing needs of automation technology for the new mega-cities?
Peter: With our wealth of practical experience, we are able to identify tomorrow's requirements at an early stage and in this era of rapid urbanisation are capable of providing our customers with customised components. Our experienced industrial managers advise plant operators all over the world in relation to safety in energy production and support them in the selection of suitable solutions for maintaining operational safety in accordance with
EN 61508.