Instrumentation Monthly Test | Measurement | Control
Watlow®, an industry leader in the design and manufacture of complete thermal systems, is pleased to announce that its EZ-ZONE® EZK, a remote user interface (RUI) that can also be used as a communication gateway, is now available with an option for Class 1, Division 2, temperature class T4A for use in hazardous locations.
The EZ-ZONE RUI can be utilized as a communications gateway device to save cost, space and wiring when digital communications are being used with two or more EZ-ZONE® controllers. It can also serve as a display for showing all parameter values for up to 16 EZ-ZONE controllers, which helps improve user system interface. As a communications gateway, it can deliver multiple communication protocol options and can connect EZ-ZONE controllers to communication networks utilizing Modbus® RTU, DeviceNet™, EtherNet/IP™, Modbus® TCP and PROFIBUS DP.
Electrical devices used in hazardous areas need to be certified for use according to the requirements specified for the area. The types of protection required depend on the risk involved in the area. In general hazardous locations in North America are separated by class, division and temperature class to define the level of safety required for equipment installed in these locations.
Class defines the general nature of hazardous material in the surrounding atmosphere and Class 1 states an area is hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures.
Division defines the probability of hazardous material being present in an ignitable concentration in the surrounding atmosphere. Division 2 states the substance referred to by class is present only in abnormal conditions, such as a container failure or system breakdown.
The temperature class is used to designate the maximum operating temperature on the surface of the equipment, which should not exceed the ignition temperature of the surrounding atmosphere. A T4A temperature classification states that the surface temperature of a piece of electrical equipment will not rise above 248°F (120°C).