J&D's VFD has a signal isolator which allows a 0-10V or a 4-20 milliamp signal to be used to control or change the speed that the VFD is outputting to the motor. If an application does not require a electric motor to run at full speed, the VFD can be used to ramp down the frequency to meet the requirements of the application. 
FEATURES
Use to vary speed to match needs based on application and to improve efficiency
Will not interfere with ear tags or other electronic devices that are susceptible to radio frequency interference due to its internal RF filter
Starts fan slowly to extend the life of the fan
NEMA 4X enclosure with cooling fins to withstand the harshest environments
Helps reduce energy consumption and energy costs
