GDS Instruments Automatic Oedometer System (GDSAOS) is the modern replacement for a traditional hanging weight oedometer.

The GDSAOS is a self-contained stepper motor driven unit that can be controlled either manually using its Smart Keypad or from a PC using the USB interface.

There is no requirement for compressed air or manually placed weights. The GDSAOS is available with a standard or long-stroke frame both of which can be upgraded to perform constant rate of strain and unconfined compressive strength testing.