This unit is used on vehicles that have propel transmission. It uses a foot pedal to control it. You can preset speed settings for it to run better, to stop it easily, use the emergency stopping while using a clutch and brake pedals, use the inching implement smoothly and use preset road speeds with foot pedal.
To use the control by cross porting the servo cylinders by means of a metering orifice. Using your manual displacement control and the inching control is like having a tandem control. You will need to use the MDC lever must be used first, it is the primary implement that directs the body and makes sure it does the commands of the swashplate angle. The inching part is used secondary, but can be made to the primary.
If you use it as the main control, then the standard part has to be initiated first so you can tell the pump the direction of the swashplate. This control main use is to control pressure that is between the control pressure ports and tell the swashplate location in the before hand biased direction. The slots in the inching valve rotary spool give the one that operates it a easier acceleration and de-acceleration of the unit.
When you use the control that way, the plate orifice situated in the control valve housing inlet needs to be 1.85 max. size for standard function. While it is in neutral setting, your pressure is obstructed off by the MDC valve spool. If you have the rotary inching spool, in the diagram it shows it closed. You can see it by a drilled hole near the top of the valve control shaft. When the spool is in neutral state, both of the spring loaded servo pistons go to the pump case, when in MDC.
When your inching control is brought back to the metering state the pressure of the control is regulated to the servo piston to sustain the swashplate location.
If you need more details on the MDC Inching Control, call us at 662-871-8403
tupelohydraulics@gmail.com