RE 66171/2020-02-17

Replaces: 03.2019

Load-sensing directional valves

in sandwich plate design
SB24-EHS, SB34-EHS
▶▶ Series 1X
▶▶ Maximum working pressure 250 bar
▶▶ Maximum flow
–– SB24-EHS with flows up to 120 l/min
–– SB34-EHS with flows up to 170 l/min

Features Contents
▶▶ Load-sensing system CAN bus in the tractor 2
▶▶ Load pressure independent flow control Functional description 3
▶▶ Type of actuation Modular system 4
–– Electrohydraulic with on-board electronics Technical data 5
▶▶ Flow Hydraulic functions 7
–– Load pressure-compensated Dimensions 14
–– High repetition accuracy Product identification 17
–– Low hysteresis Installation position 17
Electronic functions 19
Fields of application Related documentation 23
▶▶ Tractors Abbreviations 24
▶▶ Agricultural machinery Spare parts 24

 RE 66171/2020-02-17, Bosch Rexroth AG

2 SB24-EHS, SB34-EHS | Directional valves
CAN bus in the tractor

CAN bus in the tractor

With the increasing use of electronics in the field of agricul-

1
tural tractors, the Controller Area Network (CAN) devel-
oped by Bosch has become an established means for data 2 5

exchange among individual CAN devices. 3 4

SRC
This serial data bus connects CAN devices with equal rights
and coordinates the data exchange in the form of digital CAN
CAN messages. !

P
CAN features 6 R
LS
▶▶ Self-diagnostics and automatic repeat transmission in
the event of damaged or incomplete messages 7
▶▶ Linking and thus simultaneous communication possible 8
among several sensors, control units and display units. 9
CAN
▶▶ Worldwide recognized standard, ISO 11898 and 11519-2 10 11

ISig [V]
as well as SAEJ 1939.
▶▶ Less cabling makes for reduced installation space and
lower costs, and reduces risk for damages.
t [ms]
▶▶ High fault tolerance and high security of the interface.
▶▶ Diagnostics capabilities with error messaging.
1 Control panel 7 Control block
2 Fingertip control 8 CAN signal
3 Front EHR 9 CAN message
4 Rear EHR 10 ID
5 Electronic control units 11 Signal
6 Instrument cluster

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 3
 Functional description

Functional description

SB24-EHS and SB34-EHS are pilot-controlled, electrohy- ▼▼ SB24-EHS with one check valve in B port

draulically actuated directional valves with four spool posi-

tions and on-board electronics. 11 8 7 4 3 2 1 2 4
The control spool is actuated by a 4/3 directional pilot A B
control valve which pressurizes the chambers for moving
the control spool. The control spool position is fed back by
means of a position transducer to the electronics unit. R

Using the current of the pilot control valve, the electronics

then regulates the position of the control spool as a func-
tion of the requested setpoint value. Hence, the required P

flow to operate the connected equipment is therefore set at

the consumer ports.
The individual pressure compensator (IPC) maintains a 9 6 5
constant pressure drop across the meter-in control edge of
the control spool in order to maintain a load-pressure-inde-
pendent flow control over the entire adjusting range, even ▼▼ SB34-EHS with two check valves and optional manual override

in parallel operation (load compensation).

The SB24-EHS valve is equipped with a check valve B and 11 8 7 4 3 1 2 1 2 4
the SB34-EHS valve with two virtually leak-free check A B
valves A, B.
The mechanically actuated check valves allow free flow to
R
the consumer but otherwise remain open closed until
mechanically shifted open by the main spool to allow return
flow. In the SB24-EHS, the check valve function for the
P
consumer port (A) is implemented via the third switching
position of the IPC. This prevents a return flow in P in the
event of undersupply in parallel operation.
9 6 5 10
Features
▶▶ Double-acting with four positions (Neutral, Lift, Lower,
1 Check valves
Float)
2 Consumer ports
▶▶ Mechanically actuated check valves: 3 Centering springs
–– SB24-EHS in B 4 Spool end chamber
–– SB34-EHS in A and B 5 Individual pressure compensator (IPC)
6 Control spool
▶▶ Check valves open in float position without load
7 Electronics / Printed circuit board (PCB)
pressure 8 Position transducer
▶▶ SB24: 3-way individual pressure compensator 9 Pilot control valve
SB34: 2-way individual pressure compensator 10 Spring cap or spring cap with manual override
11 Electrical connector (CAN control)
▶▶ Optional flange surface for customer-specific coupling
housing
▶▶ Optional thermal pressure relieve valve integrated in the
check valve

 RE 66171/2020-02-17, Bosch Rexroth AG

4 SB24-EHS, SB34-EHS | Directional valves
Modular system

Modular system

The SB24/34 valve program is modular, allowing SB24-EHS ▼▼ Example 1: Block configuration SB24 with connecting plate
(AP) and end valve (EVL)
and SB34-EHS sections with electrohydraulic actuation,
SB24-M sections with mechanical actuation as well as
AP SVL SVL SVL EVL
EHR24-EHS or EHR24-EM2 hitch valves to all be combined
into control blocks for various applications. For further P
information, see data sheet 66170: Control block B B B B
SB24/SB34.
LS signal to
The valve sections are available in the versions standard the pump
valve (SVL) with machined faces on both sides as well as R
A A A A
end valve (EVL) and connection valve (CVL) each with only
one face machined. The end valve has no external porting
and does not have a load sense shuttle valve or O-rings on
▼▼ Example 2: Block configuration SB24 with central connecting
the machined face. The connection valve has an external
plate (ZAP), connection valve (CVL) and end valve (EVL)
load sense to connect with the variable displacement
pump and O-rings on the machined face. CVL SVL SVL ZAP SVL SVL EVL

▼▼ Connection valve (CVL), standard valve (SVL) and end valve (EVL) P
B B B B B B
CVL SVL EVL
LS signal to
the pump
P P P R
A A A A A A
B B B

Y Y

▼▼ LS sense direction “left”

R R R
A A A
Y2
Y Y2

An end valve (EVL) can take the place of an end plate (with- Y1
Y1
out hydraulic function) (Example 1).
Y
For control blocks with a central connecting plate (ZAP), a WV1 WV2

connection valve (CVL) can replace a separate connecting

plate (without hydraulic function) (Example 2). Ports

Each valve section forwards its load pressure signal to the P Pump supply port

subsequent valve via the LS channel. The section’s shuttle A, B Consumer port

valve compares the two load pressures and passes on the X Pilot oil supply

higher one towards the connecting plate and/or the con- Rx Pilot oil return line

nection valve. Hence, the highest load pressure of all valve Y LS signal

sections is signaled to the variable displacement pump via R Return flow (to tank or reservoir)

the LS output of the control block. The standard direction

Notice
of the LS signals is “left”.
With CVL and EVL the P and R channels on the unma-
chined valve side are closed with screw plugs. These
ports must not be opened and/or used for connecting
additional functions!

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 5
 Technical data

Technical data

General SB24-EHS SB34-EHS

Weight kg 6.3 8.2
Additional weight manual kg – 0.3
override
Installation position See page 17
Line connections See page 17
Ambient temperature range ϑ °C -35 to +110

Hydraulic SB24-EHS SB34-EHS

Nominal working pressure P pnom bar 210
Maximum working pressure P pmax bar 250
at the port A, B pmax bar 250
R, Rx pmax bar 20
X pmax bar 50
Neutral circulation pressure for P→R p bar 4.6 with qv nom = 100 l/min –
opening the IPC from the check 7.1 with qv nom = 120 l/min
function
Flow at port P → A, B qv nom l/min 100, 120 100, 140, 170
A, B → R qv max l/min 214 250
Leakage A→R qL ml/min ≤ 60 ≤2
without check valve in A with check valve in A
B→R qL ml/min ≤ 2 with check valve in B
Cracking pressure of thermal pressure relief valve (optional) p bar 311±69
Hydraulic fluid Mineral oil (HL, HLP) according to DIN 51524, see data
sheet 90220
Other hydraulic fluids on request, e. g. environmentally-
friendly fluids according to ISO 15380 as specified in
data sheet 90221, on request.
Hydraulic fluid temperature range Maximum ϑ °C −35 to +110
Recommended1) ϑ °C +35 to +80
Viscosity range Maximum ν mm²/s 7 to 8000
Recommended1) ν mm²/s 20 to 100
Maximum admissible degree of contamination of the hydraulic fluid Class 20/18/15, we recommend a filter with a minimum
Cleanliness level according to ISO 4406 (c) retention rate of β10 ≥ 75

1) Operation outside the recommended ranges may result in limited

service life and function.

 RE 66171/2020-02-17, Bosch Rexroth AG

6 SB24-EHS, SB34-EHS | Directional valves
Technical data

Electrohydraulic
Relative duty cycle 100% on-time to +110 °C1)
Type of protection IP66, IP67 and IP69K
(with installed and locked plug-in connector)
Connector version AMP Junior Timer, 4-pin
Electrical power consumption Pmax W 17 for 12-volt system
Supply voltage Unom V 12 vehicle electrical system ISO 16750-2: Code C
Spool shift times (neutral to full flow) See actuating time/dynamics on page 11
Pilot oil pressure bar 17 to 22, referenced to return flow pressure
Control flow per directional valve Neutral l/min 0.25
(typical) Control position lifting/lowering l/min 0.6
Briefly at max. actuating speed l/min 3.5
Actuating time/dynamics Step function ms 0 → 1/2: 70
(measured at 50 °C, (incl. dead time) 0 → F: 100
30 mm2/s, VG46)
Hysteresis relative to flow Typically approx. 1% of qnom
(in flow range up to 80% of qnom)
CE marking according to Machinery Directive Conformity with EMC Directive:
EN ISO 14982: 2009

Notice
▶▶ For applications outside these parameters, please
consult us!
▶▶ The technical data were determined with a viscosity
range of ν = 30 mm2/s and a temperature of
ϑ = 50 °C.
▶▶ The stated check valve leakage values refer to a
pressure of p = 125 bar.
▶▶ For further technical data, see
–– EHS interface description Z 206 803 930

1) Detailed information on request

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 7
 Hydraulic functions

Hydraulic functions

Example configurations SB24-EHS

Type Features
––Standard valve (SVL)
R Y P X Rx
––Check valve in B
A
B ––Without thermal pressure relief valve

2.F

F 2 0 1

––Connection valve (CVL)

R Y P
––Check valve in B
A
B ––Without thermal pressure relief valve

2.F

F 2 0 1

X Rx

––End valve (EVL)

R Y P X Rx
––Check valve in B
A
B ––With thermal pressure relief valve

2.F

F 2 0 1

0 = Neutral
1 = Lift
2 = Lower
F = Float

 RE 66171/2020-02-17, Bosch Rexroth AG

8 SB24-EHS, SB34-EHS | Directional valves
Hydraulic functions

Example configurations SB34-EHS

Type Features
––Standard valve (SVL)
R Y P X Rx
––Check valve in A and B
A
B ––Without thermal pressure relief valve
––Without manual override
1.F 2.F

F 2 0 1

––Standard valve (SVL)

R Y P X Rx
––Check valve in A and B
A
B ––With thermal pressure relief valve
––With manual override
1.F 2.F

F 2 0 1

––End valve (EVL)

R Y P X Rx
––Check valve in A and B
A
B ––With thermal pressure relief valve
––Without manual override
1.F 2.F

F 2 0 1

0 = Neutral
1 = Lift
2 = Lower
F = Float

Bosch Rexroth AG, RE 66171/2020-02-17

  Directional valves | SB24-EHS, SB34-EHS 9
 Hydraulic functions

Switching capacity limits Flow resolution

The maximum switchable return flow is dependent on the The characteristic curves apply for standard versions
load pressure level. The flow forces at the spool have a (meter-in flow calibration).
limiting effect here. Other tolerances can occur for special versions or special
The values represented refer to the pilot pressure 17 bar. spool versions.

▼▼ Characteristic return flows, switching capacity limits ▼▼ Characteristic curve for flow resolution

250 2.5
205 SB34-EHS
200 185; 204 1
2.0
200

Flow resolution [l/min]

175; 144
150 2
Δp [bar]

100; 250 1.5

3
100
SB24-EHS 4
1.0 5
50 6
50; 214 7
8
0 0.5
0 50 100 150 200 250 300
Flow qV [l/min]
0
0 20 40 60 80 100 120 140 160 180
Flow qV [l/min]

1 qnom = 170 l/min (maximum)

2 qnom = 140 l/min (maximum)
3 qnom = 120 l/min (maximum)
4 qnom = 100 l/min (maximum)
5 qnom = 170 l/min (typical)
6 qnom = 140 l/min (typical)
7 qnom = 120 l/min (typical)
8 qnom = 100 l/min (typical)

For return flow edge comparison, the tolerances only apply

above 10% of the nominal flow (greater tolerances are to
be expected below this value).

Hysteresis
With respect to the flow:
▶▶ Typically approx. 1% of qnom
(in flow range up to 80% of qnom)
▶▶ maximum 2% of qnom

Temperature drift of flow

The temperature dependence of the flow is compensated
electronically in the temperature range 30 °C to 90 °C.

Pressure drift of flow

Pressure drift of the flow (pressure increase due to parallel
operation) is compensated by the individual pressure com-
pensator.

 RE 66171/2020-02-17, Bosch Rexroth AG

 10 SB24-EHS, SB34-EHS | Directional valves
Hydraulic functions

Pressure drops (typical values)

SB24-EHS, 1 check valve SB34-EHS, 2 check valves

▼▼ Position 1 (Lift) ▼▼ Position 1 (Lift)

25 45
42.5
40
20 35

Pressure drop Δp [bar]

Pressure drop Δp [bar]

A→R
30
15
25
20
10
9.5 15
Y→B 7.1 A→R 15.0
10
5 5.1 6.1 10.2 Y→B
5
5.3
0 0
0 20 40 60 80 100 120 140 160 180 200 220 0 25 50 75 100 125 150 175 200 225 250
Flow qV [l/min] Flow qV [l/min]

▼▼ Position 2 (Lower) ▼▼ Position 2 (Lower)

25 45
38.7
40
20 35
Pressure drop Δp [bar]
Pressure drop Δp [bar]

30
15 B→R
25
10.7
B→R 20
10
15
7.9 10 13.5
5 Y→A
5.7 5 9.2 Y→A
3.9 4.9
0 0
0 20 40 60 80 100 120 140 160 180 200 220 0 25 50 75 100 125 150 175 200 225 250
Flow qV [l/min] Flow qV [l/min]

▼▼ Position F (Float) ▼▼ Position F (Float)

50 60
56.5

50
40
Pressure drop Δp [bar]
Pressure drop Δp [bar]

40
30 A→R 32.3
30
18.8 A→R
20
20

10 B→R
10
10.8 B→R

0 0
0 20 40 60 80 100 120 140 160 180 200 220 0 25 50 75 100 125 150 175 200 225 250
Flow qV [l/min] Flow qV [l/min]

Bosch Rexroth AG, RE 66171/2020-02-17

  Directional valves | SB24-EHS, SB34-EHS 11
 Hydraulic functions

Pilot pressure Actuating time / dynamics

pX = 17 to 22 bar Base frequency in relation to spool stroke approx. 14 Hz for
(setting point for control flow 0.8 to 1.2 l/min) setpoint change from 0 to 100%

The pilot pressure in accordance with the diagram must ▼▼ Characteristic curve for step function

be available alone to the EHS valves, since the full valve 10000
performance is otherwise not guaranteed.

▼▼ Characteristic curve for pilot pressure

1000
24

Time [ms]
1
22
2
20 3
100
18
Pilot pressure [bar]

16
14 4 5 6
10
12 10 100 1000 10000
10 Viscosity [mm2/s]

8 1 Actuating time: Neutral to Float

6 2 Actuating time: Neutral after Lower
3 Actuating time: Neutral after Lift
4 maximum
minimum 4 Actuation delay time: Neutral after Float
2 Setting 5 Actuation delay time: Neutral after Lower
0 6 Actuation delay time: Neutral after Lift
0 1 2 3 4 5 6 7 8 9 10
Pilot oil flow [l/min]
Thermal pressure relief valve
Optional pressure relief function integrated in the check
Pilot oil cleanliness valve, which prevents an impermissible high pressure devel-
Special attention must be paid to the cleanliness of the oil oping between the valve and the quick couplers installed.
for the pilot oil supply; additional pilot oil fine filters must Such pressure peaks can occur when the oil volume
be used if necessary. enclosed heats up, for example. The pressure is relieved
internally in the valve.

▼▼ Symbol T-PRV

Consumer port B

2.F

 RE 66171/2020-02-17, Bosch Rexroth AG

 12 SB24-EHS, SB34-EHS | Directional valves
Hydraulic functions

Internal leakage Manual override for control spool

Leakage in consumer port SB24-EHS with 1 check valve (optional for SB34-EHS)
B → R in position 0: 2 ml/min ▶▶ Mechanical manual actuation
A → R in position 0: 60 ml/min (standard) ▶▶ Operable with standard tools (hex width 13 mm)
A → R in position 2: 150 ml/min (typical)
(Check function IPC) 300 ml/min (max.) 1
Leakage in consumer port SB34-EHS with 2 check valves
F 2
A, B → R in position 0: 2 ml/min
Leakage P to R in various spool positions 2
36°
P → R in position 0: 60 ml/min (typical) 23°
250 ml/min (max.)
0
P → R in position 1, 2: 100 ml/min (typical) 23°
250 ml/min (max.)
1
P → R in position F: 60 ml/min (typical)
250 ml/min (max.)

Additional leakage values on request.

High values can occur for specific spool versions.
Notice
▶▶ Check valve leakage values measured with p = 125 bar,
ν = 30 mm2/s, ϑ = 50 °C, twaiting time = 15 s,
tmeasuring time = 60 s. = Lift
▶▶ Leakage P → R measured with p = 200 bar. = Lower
= Neutral
▼▼ Typical check valve leakage over time = Float

3.5 140
1 Position mark, milled off edge of hexagon
2 Hex width 13 mm, max. wrench width 6.5 mm, actuation torque
3 120 max. 10.5 Nm permitted
Pressure [bar], temperature [°C]

p [bar]
2.5 V [ml] 100
θ [°C] Notice
Leakage [ml/min]

q [ml/min]
2 80 Valves with manual override must be actuated mechani-
cally after painting. The actuation force to break the layer
1.5 60 of paint between the rotating setting shaft and housing
could be too high for the electrohydraulic actuation.
1 40 The valves in the tractor must be arranged such that dirt
does not accumulate at the setting shaft, preventing the
0.5 20 spool from moving.

0 0
0 1 2 3 4 5 6 7 8 9 10
Measuring time Time [min]

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 13
 Hydraulic functions

Pilot oil supply

The pilot oil supply is not part of the directional valve but
part of the block or system.

Required control flow per EHS directional valve (applicable

to SB-EHS and EHR-EHS)

▼▼ Values for a viscosity of 30 mm2/sec

In neutral position typically 250 ml/min

maximum 460 ml/min
In Lift or Lower mode typically 600 ml/min
maximum 600 ml/min
In Float mode typically 250 ml/min
maximum 460 ml/min
During step function typically 3.5 l/min
(Lift or Lower mode) (Actuating time approx. 40 ms,
no ramp)
During step function typically 4.4 l/min
(Float mode) (Actuating time approx. 75 ms)

Demand peaks in the pilot oil limited by

▶▶ Avoiding simultaneous connection of several consumers
(delay by actuating time + safety distance)
▶▶ Programming in time ramps

Control pressure referencing

The pilot oil pressure px must be referenced to the highest
return flow pressure of all EHS valves.
(px abs. = px + pR max)

 RE 66171/2020-02-17, Bosch Rexroth AG

14 SB24-EHS, SB34-EHS | Directional valves Dimensions [mm]
Dimensions

Dimensions

▼▼ Standard valve SB24-EHS

245.4±1 10.9±1.5
2

98.6±0.3
61.3±1.5

P
X Y

47.5±1.5
Rx

224.7±1.5

106.8±0.4
22±0.4

14.4±0.3 30.6±0.4

A B
44±0.3

32

76.2
16±0.1

4×M6; 8.4
98.2

4
50

33
3

1 Electrohydraulic actuation (actuating unit EHS)

2 Three holes drilled through for mounting
3 Connector removal dimension
4 A and B consumer ports in flange design
(optional M22 × 1.5 threaded ports)
5 Name plate

Bosch Rexroth AG, RE 66171/2020-02-17

Dimensions [mm] Directional valves | SB24-EHS, SB34-EHS 15
Dimensions

▼▼ End valve SB34-EHS

⌀
22
+ 106±0.5
-0 0.6
.2

22±0.5
288.5±1 20±1.5
2

98.6±0.3
61.3±1.5

47.5±1.5
44±0.5

1
267.8±0.5

106.8±0.4
22±0.4

30.6±0.4

A B
51.8±0.6

76.2

Rx LS P
X

R
50

33
3

1 Electrohydraulic actuation (actuating unit EHS)

2 Three holes drilled through for mounting
3 Connector removal dimension
4 A and B consumer ports M22 × 1.5 or M27 × 2 threaded ports
(optional in flange design)
5 Name plate

 RE 66171/2020-02-17, Bosch Rexroth AG

16 SB24-EHS, SB34-EHS | Directional valves Dimensions [mm]
Dimensions

▼▼ Standard valve SB34-EHS with manual override

288.5±1 59±0.5
2

98.6±0.3
61.3±1.5

P
X Y

47.5±1.5
Rx
1

267.8±1.5

106.8±0.4
22±0.4

14.4±0.3 30.6±0.4

A B
44±0.3

32
76.2
4×M6; 8.4 16±0.1
98.2

4
50

33
3

1 Electrohydraulic actuation (actuating unit EHS)

2 Three holes drilled through for mounting
3 Connector removal dimension
4 A and B consumer ports in flange design
(optional M22 × 1.5 or M27 × 2 threaded ports)
5 Name plate

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 17
 Product identification

Thread design of A and B consumer ports Installation position

Version I Installation position SB24-EHS and SB34-EHS without

▶▶ DIN 3852-1 (metric thread) manual override
–– For seal ring sealing
Installation position
1
0° 0°
Version II (preferred version) +10°
° +45
▶▶ EN ISO 6149-1 (metric thread) −45° −45 °
–– Without thread marking
–– For O-ring sealing
R

Version I Version II P
X Y
Rx

2
0° 0°
° +10 ° +45
−45 ° −45 °

3
0° 0°
° +10 ° +45
−45 ° −45 °
Product identification

The valve sections are identified by a 26 × 15 mm adhesive A B

label containing a data matrix code (6 × 6 mm) which

includes an encoded unique serial number. 4
0° 0°
° +45 ° +45
For unpainted products, the adhesive labels are protected −45 ° −45 °

by an additional protective film.

Rx
Y X
P

FD: XXXXX R

MNR: XXXXXXXXXXXX 5
0° 0°
SN: XXXXXXXXXXXX −45
° +45
° −45
° +45
°
CNR: XXXXXXXXXXXX
Made in XXXXXXX XXXXX
P

B
Y
R

Rx

A
X

 RE 66171/2020-02-17, Bosch Rexroth AG

18 SB24-EHS, SB34-EHS | Directional valves
Product identification

Installation position SB34-EHS with manual override

Installation position Installation position
standard version Special version with manual override upwards
1 1
0° 0°
+10°
−5° ° +45
−45 °

–
R

P
X Y
Rx

2 2
0° 0° 0° 0°+
+10 ° +45 ° ° 25°
−1
0 °
° −45 ° −45 −45

3 3
0° 0°
+10 ° +45
−5° ° −45 °

A B

4 4
0° 0° 0° 0°
° +10 ° +45 ° +10 ° +45
−45 ° −45 ° −45 ° −45 °

Rx Rx
Y X Y X
P P

R R

5 5
0° 0°
+45 ° +45
0 ° ° −45 °
−2
P

B
Y

–
R

Rx

A
X

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 19
 Electronic functions

Electronic functions

Standard: CAN control

General electrical information
Supply voltage Standard at 12-V vehicle electrical system
Voltage range 11 to 16 V
(from 9 V with restricted performance; CAN communication from 5.5 V)
Overvoltage resistance Supply: max. 28 V (25°C), duration 5 min
Reverse polarity protection Test voltage −28 V (25°C), duration 5 min
Resistance to short circuits Short-circuit protected against 36 V, against ground, and between the individual inputs and
outputs.
Type of protection IP69K (electronics), with connected mating connector
Electromagnetic interference ISO 11452-2
Measurement of electromagnetic interference 0.2 Mhz to 1000 Mhz, frequency according to
ISO 14982: 2009
Reference values:
––Absorber chamber 100 V/m
––Stripline 150 V/m
Electromagnetic emissions ISO 14982: 2009
ESD ISO 10605: 2008
Unpowered test: relay discharge: ± 8 kV, air discharge ± 15 kV, Ri = 2000 Ω,
C = 150 pF (table C1, category 1)
Powered up test: relay discharge: ± 8 kV, air discharge ± 15 kV, Ri = 2000 Ω,
C = 330 pF (Table C2, Category 1)
Line-bound transient interference ISO 7637-2:2004
Electrical power consumption UBat = 14 V
typ. [W] max. [W]
in neutral position 0.7 0.9
During max. actuating speed 12
in positions 1 or 2 3.6 5.0
In float position 6 12
Input signal CAN, physical layer according to ISO 11898 “High Speed”, standard transmission rate of 250
kBaud
Pin assignment 4-pin AMP Junior Timer connector
Pin 1 = UBat
Pin 2 = CAN low
Pin 3 = CAN high
Pin 4 = ground
Sinus vibration test DIN EN 60068-2-6, 1
 0 Hz – 2000 Hz, 57.5 → 2000 Hz, 6.93 g rms
10 Hz → 57.5 Hz, 1.5 mm pp
Broadband noise test DIN EN 60068-2-64, 5 Hz – 2000 Hz, aeff 86.9 m/s2
Shock test DIN EN 60068-2-27, a = 500 m/s2, 11 ms, 60 cycles
DIN EN 60068-2-29, a = 400 m/s2, 6 ms, 300 cycles

Notice
The on-board electronics is designed for a service life of
10 years operating time and 5 years storage time (within
the recommended temperature range). After this time,
the probability of error may increase. The operating time
is not monitored by the on-board electronics itself. The
machine manufacturer is responsible for monitoring and
determining suitable measures (e.g. test or maintenance
intervals).

 RE 66171/2020-02-17, Bosch Rexroth AG

20 SB24-EHS, SB34-EHS | Directional valves
Electronic functions

Reading fault codes with EHS diagnostic tool, fault Notice

interpretation Failsafe: In case of power failure, short-circuit or oil sup-
The EHS diagnostic tool is a software that was specifically ply failure, the actuating unit automatically sets the con-
designed for troubleshooting in EHS systems in the vehicle trol spool to neutral (the spool is spring-centered).
and/or on the test bench. The diagnostic tool is used to
identify and diagnose individual valves or all valves in the
Overview for internal diagnosis
block/tractor. The characteristics and fault memories of the
Special protection measures against malfunctions due to
valves can be read via RS232 (only individual valves) or
contamination, material defects, etc. are not provided. The
CAN (all valves). The baud rate is set permanently to 9600
device does not fulfill any safety functions without the user
Baud for RS232; for CAN, the baud rate is determined
taking additional measures.
automatically.
Fault detection Fault Fault reaction
Internal fault Control spool is not in neutral position during CAN: Diagnostic message via CAN bus
switch on Attention: uncontrolled load movements are possible; the sys-
tem must be shut off.
Spool valve is deflected too little Valve is switched to neutral; optionally, only with an fault mes-
sage
The control spool is deflected too far and/or does If the valve OBE cannot correct the spool position, the actuating
not return to neutral (e.g. spool is retained or stuck) unit is de-energized.
CAN: Diagnostic message via CAN bus
Attention: uncontrolled load movements are possible; the sys-
tem must be shut off.
Defective position transducer The valve is not actuated
Defective current measurement The valve is not actuated
Defective output stage The valve is not actuated
Checksum fault regarding The valve is not actuated
––Main program Checksum test; optionally, only fault message or shutdown
––EEPROM customer area
RAM fault Test; optionally, only fault message or shutdown
Computer fault Fault due to noise peaks:
Restart is only permitted if the setpoint was set to neutral before.
Other computer faults:
CAN: Diagnostic message via CAN bus
Attention: uncontrolled load movements are possible; the sys-
tem must be shut off.
External faults Supply voltage is below the admissible range The valve is not actuated (for CAN: optionally fault message only
if above the Bosch limit)
Supply voltage is above the admissible range The valve is not actuated (for CAN: optionally fault message only
if below the Bosch limit)
Setpoint voltage is below the admissible range The valve is not actuated
Setpoint voltage is above the admissible range The valve is not actuated
Setpoint message missing (only for CAN) The valve is not actuated
Implausible setpoint value message (only for CAN) The valve is not actuated
Configuration message missing (only for CAN) The valve is not actuated
Manual actuation (using the hand lever of the valve)  alve remains switched off, no counter-reaction, no electric ac-
V
tuation possible
Visual fault display Diagnostic LED in the device connector The flashing code indicates the fault type (see flashing code)
CAN fault diagnosis The fault is transmitted with a fault code via CAN
Directly after a fault occurs, the diagnostic message is sent up to 5 times, and then every 100 ms (adjustable). The fault
code is transmitted (see description of the CAN messages).

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 21
 Electronic functions

General information about CAN control Characteristic curves for setpoint generation and time
The EHS valve is actuated via messages sent on the serial ramps
CAN interface. The messages specify a setpoint within the
four operating positions: neutral, lift, lower, and float. Characteristic curve gradient
Additional messages can be used to set the shape of the The gradient of the characteristic linear curve can be
characteristic curve, its gradient and the ramp times sepa- reduced from 100% to 0% in 255 steps by the configuration
rately for “lift” and “lower.” message in CAN mode.
Additionally, parameterization messages can be sent via
CAN to permanently set CAN baud rate and identifier, valve 255 steps can be programmed: 
number, battery voltage, etc. The valve will send fault mes- 00hex, 01hex, 02hex......FEhex
sages. 0%, 0.39%, 0.78%, ...100%

General CAN settings The value for the gradient of the characteristic curve is
Standard setting transmitted in the configuration message in CAN mode. The
Baud rate 250 kBaud, others on request default setting is 100%. The gradient for the characteristic
Scanning Single scan curve should be selected with the values shown.
Scan time At ¾ of the bit length
▼▼ Characteristic curve gradient
Synchronization edges Only edges from recessive to dom-
inant 100 FE
Size of synchronization steps SJW = 1 BTL-cycles F0
90
DC
80
Notice C8

The maximum baud rate must always be checked in the 70 B4

vehicle and is dependent on: 60 A0
Output [%]

▶▶ The data traffic on the bus 8C

50
▶▶ The efficiency of the internal hardware identifier filter, 78
which is influenced by (for example) 40 64
–– Assignment of CAN identifiers that do not affect the 30 50
valves 3C
20
–– CAN identifier set, see Technical Information: 28
Z 206 E00 444 10
14
0A
0 01
0 10 20 30 40 50 60 70 80 90 100
Input [%]

The input is the flow setpoint from the toggle or joystick

and the output is the percentage of maximum flow. Reduc-
ing the gradient will reduce the output flow available with
the toggle or joystick. It will also improve the flow resolu-
tion when higher accuracies are needed.

 RE 66171/2020-02-17, Bosch Rexroth AG

 22 SB24-EHS, SB34-EHS | Directional valves
Electronic functions

Shape of the characteristic curve Time ramps

The shape of the characteristic curve may be changed from Time ramps can be used selectively to reduce the valve
linear to highly progressive. In this way, the fine control dynamics. The ramp time is the time required to complete
behavior of the valve can be changed if required. the entire stroke (from 0% to 100% or from 100% to 0%
lifting or lowering).
15 steps may be programmed for lifting and lowering
respectively: 255 steps may be programmed for lifting and lowering
0hex, 1hex, 2hex......Ehex respectively:
linear...................progressive 00hex, 01hex, 02hex.........FEhex
0, 16, 32,............4064 ms
The value for the shape of the characteristic curve is trans-
mitted in the configuration message in CAN mode. The values for the time ramps are transmitted in the con-
figuration message in CAN mode.

▼▼ Time ramps
▼▼ Shape of the characteristic curve 01 02
050F 1E 2D 3C 4C 5A 69 78 87 96 A5 B4 C3 D2 E1 F0 FE
100
100
90
90 0
1
2 80
80
3
4 70
70 5
6 60
Output [%]

60 7
8
Output [%]

9 50
50
40
40
30
30
A 20
20 B
C 10
10 D
E
F 0
0
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
3800
4000
4200
4400
4600
4800
5000
0 10 20 30 40 50 60 70 80 90 100
Input [%] Time [ms]

The input is the flow setpoint from the toggle or joystick

and the output is the percentage of maximum flow.

Bosch Rexroth AG, RE 66171/2020-02-17

 Directional valves | SB24-EHS, SB34-EHS 23
 Related documentation

Related documentation

Document type Title Document number

Instruction manual Load-sensing control block SB24/34 66170-B
Data sheet Load-sensing control block SB24/34 66170
Load-sensing directional valves SB24-M 66172
Plates for load-sensing control block SB24/34 66173
Hitch control valves EHR5, EHR24-EM2, EHR24-EHS 66126
Mineral oil-based hydraulic fluids 90220
Repair manual Control block assembly SB24/SB34 66170-10-R
Repairing the directional valves SB24-EHS, SB34-EHS 66170-20-R
Repairing the directional valves SB24-M 66170-21-R
Repairing the on-board electronics EHS 66170-40-R
Technical information SB24-EHS, SB34-EHS interface description, hydraulics Z 206 803 930
SB24-EHS, SB34-EHS interface description, electronics Z 206 E00 444

 RE 66171/2020-02-17, Bosch Rexroth AG

24 SB24-EHS, SB34-EHS | Directional valves
Abbreviations

Abbreviations Spare parts

This documentation uses the following abbreviations: For spare parts, visit www.boschrexroth.com/spc
Abbreviation Meaning
AP Connecting plate
Contact partners for accessories and spare parts
CAN Controller Area Network
Accessories and spare parts are available
CVL Connection valve
▶▶ From the vehicle manufacturer (specialist dealer),
EHR Electrohydraulic hitch control
▶▶ From the system manufacturer, and
EHC Pre-controlled electrohydraulic actuating unit
▶▶ From your Bosch Rexroth specialist dealer.
EP End plate
EVL End valve
Rexroth sales partners can be found on the Internet at
IPC Individual pressure compensator
www.boschrexroth.com/addresses
LS Load sensing
OBE On-board electronics
If you have questions regarding spare parts, please contact
SVL Standard valve
your local Rexroth service or the service department of the
T-PRV Thermal pressure relief valve
control block manufacturer.
ZAP Central connecting plate
Bosch Rexroth AG
Robert-Bosch-Straße 2
71701 Schwieberdingen
Germany
Tel. +49 (0) 711-811-84 81
Service.ma.schwieberdingen@boschrexroth.de

Bosch Rexroth AG © Bosch Rexroth AG 2020. All rights reserved, also regarding any disposal,
Robert-Bosch-Straße 2 exploitation, reproduction, editing, distribution, as well as in the event of
71701 Schwieberdingen applications for industrial property rights. The data specified within only serve
Germany to describe the product. No statements concerning a certain condition
Tel. +49 711 811-8481 or suitability for a certain application can be derived from our information.
info.ma@boschrexroth.de The information given does not release the user from the obligation of own
www.boschrexroth.com judgment and verification. It must be remembered that our products are
subject to a natural process of wear and aging.

Bosch Rexroth AG, RE 66171/2020-02-17