String Potentiometer - Applications

Applications

String potentiometers are used to measure the position of a moving object. The measurement cable can be connected directly to the moving part, giving a constant measurement of its linear position. This simple type of measurement device has been in use by engineers and designers for about 40 years. String potentiometers are generally durable, simple to use, and inexpensive.

The original application for string pots in the 1960s was aerospace cyclic fatigue testing. Engineers designed and built these units originally to measure movement of airplane parts as they were cycled during testing. Today, the string pot is used both for testing and as a component of equipment. Common applications include:

• hydraulic cylinder position measurement,
• automotive and aerospace testing,
• factory automation,
• medical devices,
• oil and chemical,
• structural testing,
• industrial machinery,
• robotics.

Hydraulic cylinders are used in many industries such as forklifts, cranes and aerials, material handling, die-casting, oil and gas, robotics and automation. Measurement of the extension of the cylinder requires knowledge of its current position, and often a string potentiometer is used.

The string potentiometer may be connected as a three-wire tapped resistor (voltage divider), in a control circuit, or may be packaged with electronics to produce a measurement signal in a useful form, such as a variable voltage 0-10 VDC, variable current 4-20mA, pulse encoder, Bus (DeviceNet and Canbus) and RS232 communications.

Measurement ranges vary from about 1 inch to over 100 feet and are available in many appropriate package sizes.