S680 Combine | Combine Harvesters | John Deere New Zealand

Closed-center hydraulics system overview

Closed-center hydraulic pump

Main hydraulic pump

The main hydraulic functions on the S680 and S690 Combines utilize a closed-center hydraulic system. The system is equipped with a pressure-flow compensated (PFC) pump that varies the pressure and flow required to meet the immediate needs of the main hydraulic functions on the combines.

The pump only produces enough oil pressure to meet the system's demands as they occur. As a result, the pump is always in a low-pressure standby mode. The benefits of having low-pressure standby are:

Runs cooler than conventional open-center hydraulic systems
Less horsepower required
Easier engine starting

The variable-pressure hydraulic pump is an axial piston pump and features:

Piston-style design for quick response
3100-psi high-capacity output
Solid robust design
Bigger front-end attachment lift capacity
Low noise (due to pressure flow on demand)

The closed-center system is ideally suited for S680 and S690 Combines that typically operate larger/wider headers because it:

Provides pressure-based header float to better maintain the constant ground pressure required by wider, heavier heads
Features higher-flow valve blocks for the fast hydraulic response needed with larger heads
Provides improved precision control (for the operator)

Header height (raise/lower) valve block with pressure control

Header height valve block

The closed-center hydraulic system utilizes a separate header height (feederhouse raise/lower) control valve that features integrated pressure control.

The header height valve eliminates the need for an accumulator in the header raise and lower hydraulic circuit and results in:

Faster header-lift response time
More efficient control of raising and lowering the header

The header height raise/lower control valve is located on the left-hand side of the front axle frame and provides:

Close location to the feederhouse lift cylinders for faster raise/lower response
Easy-to-replace cartridge valve design (no need to replace the whole valve)
A 26 percent higher-flow capacity compared to the open-center design for easier lifting of heavier or wider heads

The header-height-valve block controls flow rates for:

Feederhouse raising and lowering
Header height sensing
Header float

Primary control valve

Primary-control-valve block

Primary valve solenoids and wire harness

The primary-control-valve block for the closed-center hydraulic system is located on the left-hand side of the separator body. The primary-control-valve block features a split electrical and valve design in that the valve block is placed on the rear side of a bulkhead panel and the electrical portion (solenoids, harnessing, etc.) is placed on the front side of the same panel.

The split design allows for easier serviceability while providing centrally located diagnostic ports. The primary-control-valve block controls flow for:

Unloading auger swing
Variable threshing speed
Folding grain tank extension/covers (if equipped)

The primary valve also features easy-to-replace cartridge valve technology (no need to replace the entire valve).

Reel lift and lateral tilt valve block

Reel-lift-valve-block location

The closed-center hydraulic system also features a separate reel lift and lateral tilt valve with proportional control. This valve provides:

Feederhouse lateral tilt adjustment – The speed can be increased or decreased if the system is too fast or slow during manual commands
Feederhouse lateral tilt sensitivity adjustment – This allows increase in sensitivity when in automatic mode if more response is needed. Decrease sensitivity if the system is not stable (jerky up and down)
Close location to the header and lateral tilt (left-hand side of feederhouse) - This enables for quicker operational response
Easy-to-replace cartridge valve design - There is no need to replace the entire valve

This valve controls flow rates for:

Reel raise and lower
Reel extend and retract
Feederhouse lateral tilt position

High-performance S-Series EvenMax cleaning system

The EvenMax cleaning system has a large cleaning shoe area and a unique, multi-leveled shoe design that provides customers with superior shoe capacity. The result is a high-performance cleaning system that reduces slope sensitivity while delivering results.

S-Series EvenMax cleaning system

The EvenMax cleaning system begins with conveyor augers located beneath the concave, where the volume of threshed material is highest, to evenly move material onto the cleaning shoe (1). The deep auger troughs provide uniform distribution of material to the cleaning shoe with less bunching, even on sloping terrain and when harvesting up or down hills.

Once grain is on the cleaning shoe, the raised-center front chaffer cleans up to 40 percent of free grain before it reaches the main chaffer (3). High-velocity air from the cleaning fan elevates any light material traveling over the end of the front chaffer, resulting in more aggressive separation of chaff and increased cleaning performance (2). The main chaffer provides grain separation from chaff as the grain passes through the main chaffer to the sieve (4).

The sieve provides proper sizing of grain from material other than grain (5). Any grain that passes through the sieve is elevated to the grain tank while some grain or material other than grain flows to the tailings return system for reprocessing. On S650, S660, and S670 Combines, the tailings material is directed back into the threshing section of the separator for additional threshing. The tailings on the S680 and S690 Combines is directed to the active tailings return system for additional threshing then directs the material back on the return pan then onto the main chaffer for additional cleaning (6).

S690 cleaning shoe with extended chaffer circled

For S680 and S690 Combines, the S-Series cleaning system also includes an extended front chaffer. The extended front chaffer (circled) provides an additional cleaning capacity to match the high throughput of the S-Series separator.

Flexible cab options

Cab view

The cab offers unsurpassed visibility, operator comfort, convenience, and productivity. The combine cab is 254-mm (10-in.) wider and 190-mm (7.5-in.) deeper than 70 Series Combines.

Deluxe cab

Operator station

The deluxe cab offers:

30 percent larger cab than the previous 70 Series Combines
Deluxe, centered operator seat
Breakaway, foldable cab-mounted mirrors with beacon lights
25 percent greater blower and increased air-quality system capacity
Non-touch CommandCenter™ display
Touch CommandCenter display (optional)
Operator seat with air suspension, swivel, fore-aft attenuation
Single-tilt steering column with telescoping controls
Convenience outlets for power
Telematics ready
Power strip bank
Business band ready
Deluxe storage
Map and dome lights
AM or FM radio ready
Tinted glass
Air conditioner and heater
Armrest controls
Two-speed and intermittent front wiper

Premium cab

Overhead view of cab interior

The premium cab includes the deluxe cab features plus:

Touch CommandCenter display
Premium, leather seat with lateral attenuation and a low-frequency suspension (optional)
Leather instructor seat with leather-wrapped steering wheel (optional)
Dual-tilt steering column with telescoping controls
Active refrigerator
Premium storage
Electric adjust, heated roof-mounted cab mirrors
Premium radio with auxiliary input jack
Pull-down front sunshade

14,100-L (400-bu) S-Series grain tank

S690 with 14,100-L (400-bu) grain tank

Grain tank sample door

John Deere designed the 14,100-L (400-bu) grain tank to match increasing yield trends and larger header sizes to increase total machine productivity. The 14,100-L (400-bu) grain tank comes with two grain-tank-level sensors to alert the operator when levels reach three-fourths and full. The grain-tank-levels are also tied into the beacon lights to alert grain cart drivers.

A convenient hinged door panel provides quick access to obtain a grain sample. The grain trough delivers grain right to the sampling area for increased safety when taking an early grain tank sample.

NOTE: The 14,100-L (400-bu) grain tank features heavy-duty final drives to support the weight associated with the grain tank. This larger grain tank also has specific tire recommendations and comes equipped with ProDrive™.

135-L (3.8-bu) per second unload rate

S690 with 135-L (3.8-bu) per second unload rate

The 135-L (3.8-bu) per second unload rate features an enclosed gearcase for quieter and quicker engagement. A strengthened drive chain gives the 135-L (3.8-bu) per second unload rate increased durability. The unloading system also features larger sheer bolts.

The 135-L (3.8-bu) per second unload rate features:

Large-diameter grain tank cross augers 25.4cm (10 in.)
Large vertical auger 43.2 cm (17 in.)
Larger-diameter unloading auger 38.1cm (15 in.) and auger tube 43.2 cm (17 in.)
Available in both general-purpose and extended-wear versions

Clean-grain system

S680-S690 clean-grain elevator assembly

The large clean-grain elevator allows columns of grain to be handled by the elevator without plugging. The drive capacity in the clean-grain elevator system comes from large drive sheaves with belt wrap, large conveyor chain sprockets and a larger clean-grain cross auger.

Key features of the clean-grain elevator are as follows:

Clean grain elevator efficiently delivers clean grain to the grain tank
Elevator chain tension can be easily adjusted from the ground
Hinged door allows complete and convenient grain cleanout
Larger lower auger, boot, and heavy-duty chain on the S690

Loading auger

Folding loading auger in field-ready position

The grain tank loading auger ensures rapid movement of grain from the clean-grain elevator into the grain tank. The auger gearbox is an aluminum case featuring large, strong bevel gears immersed in oil for constant lubrication. An abrasive-resistant shield covers the gearcase to protect it from wear in abrasive crops.

Positioned forward on 14,100-L (400-bu) grain tank to evenly fill grain tank
Designed to not push against large volumes of grain when filling the tank
Easily folds down to the transport position to reduce overall combine height
Heavy-duty loading auger gearbox on the S690

Power folding grain tank extensions and covers

Power folding grain tank extension

Power folding loading auger and extensions

The ability to fold the 10,600-L/14,100-L (300-bu/400-bu) grain tank is designed for height-restricted areas and ease of use on the S-Series Combines. The power folding extensions/covers are made of a water-resistant composite material to keep the grain tank dry when covers are closed without grain in the tank. The covers feature vinyl corners to achieve grain tank capacity and proper folding.

The power folding grain tank option is controlled from the CommandCenter™ armrest inside the cab. Not only do the covers fold, but the fountain/loading auger also folds with a simple touch of a button so there is no need to enter the grain tank.

The power folding grain tank extensions/covers option is available on the S660, S670, S680, and the S690 combines.

For visual comparison purposes, see the manual folding grain tank below:

Manual folding grain tank (14,100 L [400 bu] on a S690 Combine)

ProDrive™ propulsion system automatically shifts between two speed ranges as ground conditions change

Harvesting in rolling ground and slopes

Valuable harvest time will no longer be lost shifting on hills, on slopes, and when exiting fields to start transporting. The ProDrive propulsion system is a high-capacity feature that enables John Deere S-Series Combines to maintain high levels of productivity in all terrain and ground conditions.

The system uses powershift transmission technology to automatically shift between two speed ranges as ground conditions change, to keep the combine harvesting at the desired ground speed.

Mode one can be set for typical harvesting speeds. Mode two can be used when higher speeds are needed during harvest or when transporting the combine.

The ground speed can be infinitely varied within both modes by the operator, using the multifunction control handle on the CommandARM™ armrest console. The multifunction handle regulates the high-capacity, variable hydrostatic pump and motor that drives the ground speed.

The productivity advantages of ProDrive include the following:

Precise control of the combine speed (when going up or down hills), without the need to continuously monitor and adjust the hydrostatic control handle
No need to stop to shift between transmission gears
Automatic powershift technology between speed ranges
Operator-selected maximum speed within each mode, allowing for more precise control of the combine in delicate operations (for example, when hooking up headers)
High-capacity, high-torque ground drive performance during harvest and transport
No loss of ground speed when engaging four-wheel drive (if equipped)

The ProDrive system on S-Series Combines includes an integrated Harvest Smart™ feedrate control system to provide the maximum productivity and reduce operator stress and fatigue.

ProDrive basic specifications

The ProDrive hydrostatic motor has a higher displacement than the previous hydrostatic systems.

Both the pump and motor are variable-displacement components that allow ProDrive to maintain high levels of torque to the ground throughout each of the two operating-speed ranges.

ProDrive transmission brakes

Park brake button

ProDrive comes equipped with hydraulic wet-disc brakes; five brake discs per side provide ample braking performance during transport or when operating on hills.

When transporting, it is recommended the two independent brakes pedals be locked together. When in field mode, the brakes pedals can be pushed individually for various terrain conditions.

When the hydro handle is moved to the neutral position, the park brake is automatically engaged to prevent unintended movement and can be locked in this mode with the touch of the park brake button on the CommandARM armrest console.

An alarm in the CommandARM display alerts the operator the park brake is engaged, if it has not been released prior to hydro handle movement. When the combine engine is turned off, the park brake is automatically applied.

ProDrive system operation

ProDrive buttons on armrest

ProDrive provides operators with superior control of the combine ground drive through the CommandARM armrest console.

Using the navigation tools on the armrest, the operator can dial in the desired maximum-attainable speed within each of the two modes.

The maximum forward speed in either range can be set from 0 to 24 mph. The maximum speed in range one cannot be set higher than the maximum speed for range two.

CommandTouch™ ProDrive mph screen

For example, if a maximum harvest speed of 8 mph (13 km/h) is desired and set, the full forward position of the hydrostatic control handle will deliver the speed of 8 mph (13 km/h).

This feature provides more precise and comfortable control of the combine ground speed throughout the travel range of the hydro handle.

The adjustability of the range of speed can also make maneuvering the combine in close quarters and connecting header equipment much easier.

The ProDrive transmission is equipped with an electrohydraulic differential lock with a four-pinion differential. Non-ProDrive combines have a two-pinion differential.

When operating in muddy, hilly terrain or in sandy conditions that may cause one of the tires to lose traction, this differential lock enables the operator to maintain productivity. If traction is lost, the operator can quickly and easily engage the differential lock by pressing the differential lock button on the CommandARM armrest console. An indicator light within the button alerts the operator that the differential locking feature is engaged.

This feature eliminates the need for the operator to control the drive wheel slip manually with the independent brake pedals. When turning, the differential lock disengages automatically if one of the brakes is applied, or if the operator presses the button to disengage the differential lock.

CommandTouch™ multi-speed feederhouse drive provides extra high-torque drive capacity

CommandTouch multi-speed feederhouse drive

Left-hand side of feederhouse

The CommandTouch multi-speed feederhouse drive includes large internal reverser components to match the loads associated with larger chopping corn heads.

The drive system includes the following components to provide drive capacity exceeding that of the high-torque variable feederhouse drive:

Large internal reverser gearbox components
Multi-speed feederhouse drive transmission
High-tensile-strength belts (transmits power from the multi-speed drive transmission to the feederhouse back shaft)

When the combine is connected to a corn head, the operator can select the feederhouse speed that best matches crop conditions and ground speed on the go using the feederhouse speed button on the multi-function control handle.

When the engine is operating at 2100 rpm, the feederhouse back-shaft speed for each of the five transmission speeds will be as follows:

First gear	490 rpm
Second gear	550 rpm
Third gear	600 rpm
Fourth gear	670 rpm
Fifth gear	750 rpm

The feederhouse back-shaft speed (rpm) and current gear selection can be viewed by the operator in the CommandARM™ display and is on the set-point combine adjustment functions of S-Series Combines.

Isochronous engine governor enhances overall capacity and efficiency

Isochronous engine governor

Maximum power
Rated power

Black line = Model year 2011 engine curve (with separator on)
Yellow line = Model year 2012 engine curve (with separator on)
Green line = Unloading (with separator on)

The isochronous engine governor keeps engine speed constant until rated engine power is exceeded. Due to the constant engine speed driven components remain at constant speed too, which enhances the combine overall capacity as well as efficiency. This is gained by preventing over blowing of shoe in low-load conditions such as starting a filed, down crop conditions when leaving, entering a path, that can either end in higher shoe losses or in dirty grain tank samples.

Main benefits of the isochronous engine governor include:

Constant engine speed equals increased overall machine performance
Reduced engine operating speed equals less fuel usage
Consistent engine speed equals better durability

The cleaning shoe speed is directly proportional to the engine speed. The cleaning shoe performs best as it approaches its maximum operating speed. With non-isochronous engines, the shoe speed was calibrated to limit the maximum shoe speed proportionally to the maximum engine speed with no load. This left the shoe speed subject to falling below the optimal cleaning speed in tougher, heavier load conditions. The isochronous governor manages and maintains the engine speed throughout the array of crop conditions, leading to a more consistent, better-performing cleaning system.

The isochronous governor electronically activates only when the separator or unloading auger is engaged. Normal engine operation (higher idle) will be present when the machine does not have the separator or unloading auger engaged.

Power meter display

Power meter

Previously, engines without isochronous governors would decrease the crankshaft speed when load was applied to the engine. Operators could hear when this happened, which gave them an understanding of the amount of power the engine was being required to output. Since the isochronous governor maintains a constant crankshaft speed independently of the engine load, a display is created to aid in the operator's understanding of the power output by the engine.

A power meter in the cab gives the operator a visual reference of how much power is being used, similar to how changes in engine speed are displayed. The display features a bar graph, which shows the operator how much engine power is being used at any time.

Green – 35 to 100 percent engine load (14 bars)
Yellow – 101 to 110 percent engine load (4 bars)
Red – 111 to 114 percent engine load (2 bars)

As long as the combine is operated in the green range, it is running below rated power at constant rpms when reaching the yellow area it exceeds rated power engine rpm starts to drop. When reaching the red area, the operator is informed that the machine is close to reaching maximum power, so the operator should pay attention to the throughput of the machine.