Cylinder and Gripper Monitoring: Festo Unveils Position Transmitter

Festo has developed a new position transmitter that helps properly position pneumatic cylinders and grippers, without requiring much physical space. The SDAC-MHS position transmitter is designed to work as a compact C-slot sensor and to drastically simplify position sensing in pneumatic systems.

Festo’s SDAS-MHS for C-Slot

The SDAC-MHC position transmitter uses the Hall effect to detect the position of the piston in pneumatic actuators. It mounts along a C-shaped channel (C-slot) and can detect the change in magnetic field as the piston slides through the pneumatic cylinder. This signal is then used to position the sensor accurately.

The Festo SDAC-MHS position transmitter for cylinder and gripper position monitoring. Image used courtesy of Festo

The SDAC-MHS position transmitter is compact in size, which allows free motion of the rest of the robotic system. Often, position transmitters are bulkier, meaning motion is limited, and the payload for grippers is reduced due to the extra mass.

Position Transmitter and Proximity Switch

Festo has designed its position transmitters in two common cylinder sizes (20 mm for analog output and 30 mm for I/O-Link output), making them ideal for the small pneumatic cylinders found in grippers and precision motion systems. Furthermore, the device can act like two limit switches, meaning one position sensor replaces two separate devices and their cabling.

Each transmitter can be programmed via I/O-Link, and all data transfer is performed through a single cable. This includes two programmable switching outputs. Programming is performed through an intuitive graphical user interface. Output can be digital (24 V), such as to show when a limit has been reached, or it can be a standard 0-10 V DC analog signal. The sensor has high resolution, and changes of as little as 0.05 mm can be detected.

The SDAC-MHS is available in two sensing ranges: 20 mm (analog variant) and 30 mm (IO-Link variant). Image used courtesy of Festo

These transmitters have numerous options as well. They can be ordered in two protection levels (IP65 and IP68), two cable lengths (0.3 m and 2.5 m), and feature an M8, 4-pin connector, or can be left with no connector for custom installations.

Continuous Position Feedback

Designed for pneumatic systems, the SDAC-MHS can replace bulkier, multi-component sensing systems. The flexibility in data types (digital, analog, and IO-Link) makes it simple to integrate with existing systems.

Festo expects this sensor to be used with small pneumatic cylinders, such as those found in robotic grippers. The device's small physical footprint enables position detection without limiting the range of motion for other components in the system.

Besides continuous position monitoring, the SDAC-MHS transmitters can be used as limit switches. Pneumatic systems must not be extended or contracted beyond certain limits, given the cylinder's physical size and additional constraints for the particular system. The digital output can be used as an on/off switch to provide a safe mechanism for limiting the motion of the actuator.