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GeneralInformation

Application Hints

Junction Styles

What type of junction shouldI use?

Listed below are the junction stylesoffered by Watlow. Generally speaking, the groundedjunction ungrounded offers the best compromiseof performance and reliability. It is the best choice for general purpose measurements.Select if the lead wirewill be shielded and attached to the sheath. Also select the ungrounded junction to avoid ground loops between instruments, power supplies and the sensor. Exposed Junction Thermocouple wires are butt welded,and insulation is sealed against liquidor gas penetration. This junction styleprovides the fastest possibleresponsetime but leaves the thermo-couple wires unprotected against corrosive or mechanical damage. Grounded Junction Ungrounded Junction The sheath and conductors arewelded together, forming a com- pletely sealed integral junction. Recommended in the presence of liquids, moisture, gas or high pressure.The wire is protected from corrosiveor erosive conditions. Response time with this style approaches that of the exposed junction. On this type the thermocouplejunction is fully insulated from the welded sheath end. The ungrounded junction is excellent for applications where stray EMFs would affect the reading and for frequent or rapid temperature cycling. Response time is longer than for the groundedjunction. Two separate thermocouples areencased in a single sheath. The isolation would prevent ground loop errors if wired to separate instruments. Only available as ungrounded junctions. Ungrounded Dual Isolated Junction 22