Sensor and Controller Catalog

Think Safety

All thermal systems pose inherent hazards if applied incor- rectly. Improper application and failure to adhere to recog- nized national, state and local electrical codes as well as agency standards can result in injury to personnel or damage to plant and process. Users are responsible for determining controller or sensor-to-application compatibility. Care should always be exercised in controller or sensor selection, installation and use. Responsibility for sensor and controller installation and wiring lie with the customer. Each sensor, power and tem- perature controller is packaged with its own user manual. Be sure to review and understand the manual, which will help maximize safety, thermal system performance, efficiency and product life. All Watlow ® temperature and power controllers and sensors should be installed by qualified personnel who are knowledgeable about the thermal system’s characteristics and in accordance with the National Electrical Code and any applicable state or local codes. Sensor Safety If a sensor is used in a medical application, with life or death consequences, careful attention must be paid to its fit for the application with appropriate redundancies and/or alarms built into the product. If the sensor is used in an industrial environment where hazards exist, protection methods (isolating sensors and wiring from explosive or flammable substances) should be considered to prevent failures or short circuits from becoming dangerous to personnel and property. It is good engineering practice to always consider the consequences of a catastrophic failure and the affect it would have on personnel and property. Please institute the appropriate safeguards to limit any danger. Controller Safety The following recommendations apply to all Watlow temperature and power controllers as well as control pan- els: • Carefully read, understand and follow the instructions contained in the user manual. • Always disconnect electrical power prior to installing, servicing or replacing temperature or power controllers. • All temperature and power controllers should be used with approved conductors of the correct wire gauge. • Do not use solid state power controllers in safety limit controller circuits. Solid state components tend to fail in a closed circuit mode and will not cut off power.

• Safety limit control should be provided by an isolated, redundant sensor and agency-approved controller of the appropriate type, design and installation. • Electrical enclosures and/or control panels housing temperature and power controllers should match the application’s environment and be able to withstand worst-case failures especially in hazardous locations. • Do not apply temperature or power controllers where ambient conditions exceed specified operating environments and/or exceed power draw permitted by the device or applicable rating curve. • Pay special attention to wiring practices. Power, sensor and communications wiring should be handled appropriately to avoid inductive and capacitive coupling. These conditions can create errant and/or erratic operation and pose a safety hazard. Use noise suppression devices where appropriate. Make ground connections for any device only to the appropriate electrical ground for that device (chassis, safety or computer ground).

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