The WIKA FSD-4 is an electronic flow switch for liquid media based on the calorimetric (thermal) principle. It measures the flow velocity of water, oils, coolants and other liquids and provides flexible switching and analog outputs. The FSD-4 is completely wear‑free, with no moving parts. Switch points can be freely configured via three buttons on the instrument or optionally via IO‑Link 1.1. It can output absolute flow values in various units and relative flow values on the digital indicator.

Adaptation to Site Conditions

A teach function allows the user to set the zero point and maximum flow at the actual measuring location, optimally adapting the instrument to site conditions such as pipe diameter, system setup and medium properties. The compression fitting on the process connection provides additional flexibility: insertion depth and alignment can be individually adjusted depending on the pipe diameter.

Rotatable Display and IO‑Link Connectivity

The display and housing can be rotated 300°, allowing the indicator to be always aligned towards the operator without changing the electrical connections. The FSD-4 is used for control of cooling lubricant systems, monitoring of coolant circuits, control of filter units and dry‑run protection of pumps. It can also be used for simple temperature control processes, with the second switching output configurable for temperature.

With IO‑Link, instrument parameters can be easily backed up and replaced, and additional features such as operating hours counter or max‑value memory can be accessed for condition monitoring.

Applications

The FSD-4 is ideal for cooling lubricant system control, coolant circuit monitoring, filter unit control, and pump dry‑run protection across industrial automation, machine tools, hydraulic systems and process industries.