DATA SHEETType 8685/8686

Control- and feedback head for integrated mounting on
Robolux valves Type 2036
• Compact design• Contactless valve position registration• Coloured illuminated status display• Fieldbus AS-Interface (optional)• With ATEX II cat. 2G approval

Product variants described in the data sheet may differ from the product presentation and description.

Can be combined with﻿

Type 2036

Robolux multiway diaphragmvalve, pneumatically﻿ operated

Type description
Feedback Type 8685 and control head Type 8686 are optimized for integrated
mounting on pneumatically operated actuators Type 2036 Robolux. The adjustment to the individual actuator size is done through DIP-switches.
As compact units the devices contain the complete automation functionalityof both individually operated actuator pistons. Depending on the configuration,
electrical and visual position feedback is done by non-contact switches and LEDs,
integrated pilot valves control the actuator pistons and AS-interface communication is available. In this way a complete concept for decentralized automation isfeasible.
The compact body is especially distinguished by its hygienic design, materials
being chemically resistant against cleaning media and a proven IP protection. Inaddition the Control Head Type 8686 features an integrated compressed air filter toprotect the pilot valve function against particles through the compressed air supply.

Standard | EU | en | 2024 - 09 - 10 | 05
© Christian Bürkert GmbH & Co. KG, Subject to alteration

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Table of contents
1.

General technical data
1.1..
1.2..
1.3..
1.4..
1.5..

Control and feedback head Type 8685 and Type 8686..................................................................................................................................3
Without fieldbus communication: 24 V DC.........................................................................................................................................................4With fieldbus communication: AS-Interface Type 8685..................................................................................................................................4With fieldbus communication: AS-Interface Type 8686..................................................................................................................................4
Ex i version Type 8685 and Type 8686...............................................................................................................................................................5

2. Approvals and conformities
2.1..
2.2..
2.3..

5.

7.

13

Combination options with pneumatic process valves ELEMENT.................................................................................................................13

Ordering information
7.1..
7.2..
7.3..
7.4..

10

Electrical connections...........................................................................................................................................................................................10
Without fieldbus communication 24 V DC: Type 8685..................................................................................................................................10
Without fieldbus communication 24 V DC: Type 8686...................................................................................................................................11
AS-Interface connection: Type 8685 and Type 8686.................................................................................................................................... 12

6. Product installation
6.1..

7Type 8685.................................................................................................................................................................................................................7Type 8686.................................................................................................................................................................................................................8Type 8686 Ex i (NAMUR).......................................................................................................................................................................................9

Device/Process connections
5.1..

6

Material specifications............................................................................................................................................................................................6Type 8685.................................................................................................................................................................................................................6Type 8686.................................................................................................................................................................................................................6Type 8686 Ex i (NAMUR).......................................................................................................................................................................................6

4. Dimensions
4.1..
4.2..
4.3..

5General notes...........................................................................................................................................................................................................5Conformity................................................................................................................................................................................................................5Standards..................................................................................................................................................................................................................5

3. Materials
3.1..

314

Bürkert eShop........................................................................................................................................................................................................14
Bürkert product filter.............................................................................................................................................................................................14
Ordering chart........................................................................................................................................................................................................14
Ordering chart accessories.................................................................................................................................................................................. 15
Standard accessories........................................................................................................................................................................................... 15Adapter kits.............................................................................................................................................................................................................15

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Type 8685

1.

General technical data

1.1.

Control and feedback head Type 8685 and Type 8686

Product properties
Dimensions

Further information can be found in chapter “4. Dimensions” on page 7.

MaterialBody
Seal
CoverPPS, stainless steel
EPDM
PCCommunicationFieldbus
Performance data
Position sensor

AS-Interface

Stroke range for linear actuator
Valve spindle
Position feedback
Electrical data

RV50 = 6.0 mm, RV70 = 9.5 mm, RV110 = 13.5 mm
Reed sensors (contactless)

Operating voltage
Pilot valve

24 V DC ± 10 %Maximum input voltage 1.)
For Ex i variant: see “1.5. Ex i version Type 8685 and Type 8686” on page 5
10 %0.8 W every valve
24 V DC ± 10 %8.2 V DC (Ex i-NAMUR switch amplifier)Ui < 12 V, Ii < 20 mA, Pi < 60 mW (Ex barrier)
III according to VDE 0580

Residual ripple
Power consumption
Limit switches

Protection classElectrical connection
Multipole version
Cable gland version

M12 (8-pin), M12 (4-pin) with 1 m cable (AS-Interface)
M16 × 1.5 (cable Ø 6.5 mm), screw terminals (1.0 mm2)

Pneumatic data
Control medium
Dust content
Particle density

Neutral gases, air, quality class according to ISO 8573 - 1
Class 5 (< 40 µm particle size)
Class 5 (< 10 mg/m3)

Pressure dew point
Oil content

Class 3 (<- 20 °C)
Class 5 (< 25 mg/m3)

Air supply filter
Mesh size
Supply pressureExchangeable~0.1 mm
3…7 bar 2.)

Pilot air ports
Threaded connection G ⅛
Approvals and conformities
Further information can be found in chapter “2. Approvals and conformities” on page 5.
Environment and installation
Operating conditions
Ambient temperature
0…+ 55 °C
Degree of protection
IP65/67 according to EN 60529
Installation and mechanical data
Installation position
As required, preferably with actuator in upright position
Adapter kits
Further information can be found in chapter “Adapter kits” on page 15.
1.) Valve supply:
Maximum input power Pi = 1.1 mW
Maximum input voltage and maximum input current according to the following table
Ui [V]

1518202225283035

Ii [mA]900

440 30922415812010173

Internal capacity and inductance negligible2.) The existing supply pressure must be 0.5…1 bar above the minimum required pilot pressure of the valve actuator.

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Type 8685

1.2.

Without fieldbus communication: 24 V DC

Electrical data
Operating voltage
Residual ripple
Power consumption
Voltage tolerance
OutputElectrical connection
Multipole
Cable gland

1.3.

24 V DC10 %<2 W± 10 %Max. 100 mA per output, short-circuit protected
M12 (8-pin)
M12 × 1.5 (cable Ø 6.5 mm), screw terminals (1.0 mm2 / maximum port cross-section 0.25 mm2)With fieldbus communication: AS-Interface Type 8685

Product properties
ProfileElectrical data

S- 0.A.E (AB slave, max. 62 slaves/master)

Operating voltage
Via bus cable
Separated from bus signal

29.5…31.6 V DC
According to specification
On request

Maximum current consumption(2 terminal position reached)Electrical connection
Programming data

35 mA

1.4.

M12, 4-pin with 1 m cable on flat cable clip
See operating manual Type 8685 With fieldbus communication: AS-Interface Type 8686

Product properties
ProfileElectrical data
Operating voltage
Via bus cable
Separated from bus signal
Maximum current consumption(2 valves activated and2 position feedback active)

S- 7.A.E (AB slave, max. 62 slaves/master)
29.5…31.6 V DC
According to specification
On request
120 mA

Outputs
Contact rating
Watchdog function≤ 2 × 0.8 W (above AS-Interface)
Integrated

InputsSensor operating voltage
Current carrying capacity
Switching level High
Input current High
Input current LowElectrical connection
Programming data

24 V ± 10 % (above AS-Interface)≤ 50 mA short circuit protected≥ 10 V≤ 1.5 mA
≤ 0.1 mA
M12, 4-pin with 1 m cable on flat cable clip
See operating manual Type 8686 Visit product website 4 | 15

Type 8685

1.5.

Ex i version Type 8685 and Type 8686

Electrical data
Operating voltage
Limit switches

Operates with Ex i-NAMUR switch amplifier: 8.2 V DC
Operates with Ex barrier 1.): Max. input voltage Ui < 12 V DC
Control valve component for Ex valve coils 2.)

Pilot valve
Limit switches statusCurrent consumption

Only electrical feedback
Operates with Ex-i-NAMUR switch amplifier:< 1.2 mA (terminal position reached)> 2.1 mA (terminal position not reached)
Operates with Ex barrier 1.): Maximum input current Ii < 50 mA
Cable gland M12 × 1.5 (cable Ø 6.5 mm, screw terminals 1.0 mm2/max. port cross-section: 8685:0.25 mm2, 8686: 0.14 mm2

Electrical connection
Approvals and conformities
Explosion protection
Ignition protection class

BVS 13 ATEX E 039 X
IIG Ex ia IIC T4 Gb

IECEx BVS 13.0047 X
Ex ia IIC T4 Gb
Further information can be found in chapter “2. Approvals and conformities” on page 5.
Environment and installation
Operating conditions
Medium temperature of adapted process valve Type 2036
T (Medium): 0…130 °C (safety requirement value)1.)	Electrical feed-in through intrinsically safe electric circuit of ignition protection Ex ia IIC. Each circuit (end position) has the following safety related max data:
Maximum input voltage Ui = 12 V DC / Maximum input current Ii = 50 mA
Maximum input power Pi = 60 mW
Internal capacity and inductance negligible2.)	Valve supply:
Maximum input power Pi = 1.1 mW
Maximum input voltage and maximum input current according to the following table
Ui [V]

1518202225283035

Ii [mA]

900440 309

22415812010173

Internal capacity and inductance negligible

2.

Approvals and conformities

2.1.

General notes• The approvals and conformities listed below must be stated when making enquiries. This is the only way to ensure that the productcomplies with all required specifications.
• Not all available versions can be supplied with the below mentioned approvals or conformities.

2.2.

Conformity

In accordance with the Declaration of Conformity, the product is compliant with the EU Directives.

2.3.

Standards

The applied standards which are used to demonstrate compliance with the EU Directives are listed in the EU-Type Examination Certificate
and/or the EU Declaration of Conformity.

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Type 8685

3.

Materials

3.1.

Material specifications

Type 8685

12No.
12345

Element
Cover
Seal
Basic housing
ScrewsCable glandMaterialPCEPDM
PPSStainless steel
PANo.
12345678

Element
Cover
Outer casingScrews
Threaded ports G ⅛
Basic housing
Seal
Plug connector M12
Dummy plug

MaterialPC
EPDM
Stainless steel
Stainless steel
PPS
EPDM
Nickel-plated brass
PANo.
12345678Element
Cover
Outer casing
ScrewsThreaded ports G ⅛
Basic housing
Seal
Cable connection
Dummy plug

MaterialPC
EPDM
Stainless steel
Stainless steel
PPS
EPDM
PAPA

354

Type 8686
12678345

Type 8686 Ex i (NAMUR)
12678

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Type 8685

4.

Dimensions

4.1.

Type 8685

Note:Dimensions in mm

Ø 7.3

55.8

64.5

6

14.1

17.1

86.2

Ø 90.840°

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Type 8685

4.2.

Type 8686

Note:
Dimensions in mm

17.1

14.1

14.6

115.4

Ø 90.8

6

13.5
31.7

54.1
45

43.5

38

14.6

50.3

Ø 118

55.5

4527

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Type 8685

4.3.

Type 8686 Ex i (NAMUR)

14.6

14.4

Note:
Dimensions in mm

13.5

27

31.7

54.1

~Ø 90.8

45

43.5

38

17.1

14.1

50.3

Ø 118

64115.4.5

4540°

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Type 8685

5.

Device/Process connections

5.1.

Electrical connections

Without fieldbus communication 24 V DC: Type 8685
Cable gland
Description on circuit board
24 VGND
Top 1
Bot 1
Top 2
Bot 2

Description
Operating voltage + (24 V DC)
Operating voltage – (GND)
End positions above, Top actuator 1
End positions below, Bot actuator 1
End positions above, Top actuator 2
End positions below, Bot actuator 2

Description on circuit board
Top 1 +
Top 1 –
Bot 1 +
Bot 1 –
Top 2 +
Top 2 –
Bot 2 +
Bot 2 –

Description
End positions above + actuator 1
End positions above – actuator 1
End positions below + actuator 1
End positions below – actuator 1
End positions above + actuator 2
End positions above – actuator 2
End positions below + actuator 2
End positions below – actuator 2

Top1
Bot1
Top2

24 V GND

Bot2

Ex i (NAMUR): cable gland

Bot1 Bot1 +Top1 Top1 +Top2 +Top2 Bot2 +Bot2 -Visit product website 10 | 15

Type 8685

Without fieldbus communication 24 V DC: Type 8686
Cable gland
Description on circuitboard
Bot 2Top 2
Bot 1
Top 1
Valve 2
Valve 1GND
24 V DC

24 VGNDValve1
Valve2
Top1
Bot1
Top2
Bot2

Description
End positions below, Bot actuator 2
End positions above, Top actuator 2
End positions below, Bot actuator 1
End positions above, Top actuator 1
Valve control Y2 + (actuator 2 operated)
Valve control Y1 + (actuator 1 operated)
Operating voltage –Operating voltage +Multipole connection M12, 8-pin
Note:
Use only straight cable sockets.

654

7

3

12Pin1
23
4
5678

8

Description
Limit switches 3
Limit switches 4
Limit switches 1
Limit switches 2
Valve 2
Valve 1
GND24 V DCAssignment
End positions below, Bot actuator 2
End positions above, Top actuator 2
End positions below, Bot actuator 1
End positions above, Top actuator 1
Valve control Y2 +Valve control Y1 +Operating voltage –Operating voltage +Ex i (NAMUR): cable gland

Y1+ Y1-Y2+ Y2Actuator

Actuator

RV 50 70 110

RV 110 70 50
BTM1- BTM1+ TOP2- TOP2+TOP1TOP1+

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BTM2BTM2+

Description on circuit board
TOP 1 +
TOP 1 –BTM 1 +BTM 1 –TOP 2 +TOP 2 –BTM 2 +BTM 2 –Y1 +Y1 –Y2 +Y2 –Description
End positions above + actuator 1
End positions above – actuator 1
End positions below + actuator 1
End positions below – actuator 1
End positions above + actuator 2
End positions above – actuator 2
End positions below + actuator 2
End positions below – actuator 2
Supply line valve1
Return circuit valve1
Supply line valve2
Return circuit valve2

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Type 8685

AS-Interface connection: Type 8685 and Type 8686
Circular plug M12, 4-pin

431

2Visit product website Pin1

Description
Bus +2
3
4

NCBus –NCControl head Type 8686

Feedback head Type 8685

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Type 8685

6.

Product installation

6.1.

Combination options with pneumatic process valves ELEMENT

Note:
A complete process valve system Type 8806 consists of control head Type 8686 or position feedback Type 8685, a control valve
Type 2036 Robolux and an adapter set.
The following information is required to select a complete system:• Article no. of the desired positioner control head Type 8686 or feedback Type 8685
• Article no. of the desired control valve Type 2036 Robolux
You order two components and receive a completely assembled and tested valve.
Examples of control valve systems
Feedback headType 8685 

Type 8685
Ex Control headType 8686 Type 8686
Ex Desired process valve

Type 2036 Robolux

Complete process valve system

Process valve system withposition feedback
On/Off Robolux
Type 8806-DI-S 
Type 2036 + Type 8685

Visit product website Process valve system withposition feedback
On/Off Robolux
Type 8806-DI-T 
Type 2036 + Type 8686

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Type 8685

7.

Ordering information

7.1.

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7.3.

Ordering chart

TypeCommunication

8685

8686

Electrical connection

Without

Cable gland

AS-Interface A/B

Cable gland with 1 m
cable on flat cable clip

Ex i (NAMUR)
Without

Cable gland
M12 (8-pin)

AS-Interface A/B

Cable gland with 1 m
cable on flat cable clip
Cable gland

Ex i (NAMUR)

Pneumaticfunction
Without
Without

Position feedback Pilot air ports

Article no.

2 switching points
2 switching points

Threaded connection G ⅛
Threaded connection G ⅛

231306 231307 

Without
2x single-acting
DN 3.02x single-acting
DN 3.02x single-acting
DN 3.02 switching points
2 switching points

Threaded connection G ⅛
Threaded connection G ⅛

242249 231292 

2 switching points

Threaded connection G ⅛231293 

2 switching points

Threaded connection G ⅛

242250 

Further versions on request
Additional• Type 8686 ASI - variants with external power supply• Type 8686 24 V DC - variants with cable gland

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Type 8685

7.4.

Ordering chart accessories

Standard accessories
Note:
Must be ordered separately.
Description
M12 circular socket with cable, 8-pin, cable length: 5 m, for input and output signals
M12 circular socket with cable, 8-pin, cable length: 2 m, for input and output signals
AS-Interface flat cable clamp, M12 outlet, stainless steel outlet
Silencer G ⅛
Pilot tool for cover mounting

Article no.
919267 919061 799646 780779 674077 

Adapter kits
Note:
Must be ordered separately.
Description
Adapter set for Type 8685
Adapter set for Type 8686

Visit product website Actuator size
RV50, RV70, RV110
RV50, RV70, RV110

Article no.
684267 684268 15 | 15