Final answer:
Diaphragm valves are generally classified as manual or automatic, depending on their mode of operation.
Step-by-step explanation:
The two general classifications of diaphragm valves are manual and automatic. These categories describe the operation mode of the valves. Manual diaphragm valves are operated by hand, using a wheel or crank. Automatic diaphragm valves, on the other hand, are operated by pneumatic, hydraulic, or electric actuators. These allow the valves to be controlled remotely and can be integrated into automated systems for various applications.