SH 8387-5 EN
Translation of original instructions

Type 3731-5 Electropneumatic Positioner
Communication: FOUNDATION™ fieldbus

Edition July 2020

Definition of signal words! DANGER
Hazardous situations which, if not avoided,
will result in death or serious injury! WARNING
Hazardous situations which, if not avoided,
could result in death or serious injury

2! NOTICE
Property damage message or malfunction
Note
Additional information
Tip
Recommended action

SH 8387-5 ENPurpose of this manual
The Safety Manual SH 8387-5 contains information relevant for the use of the Type 3731-5Positioner in safety-instrumented systems according to IEC 61508 and IEC 61511. The safety
manual is intended for planners, constructors and operators of safety-instrumented systems.
! NOTICE
Risk of malfunction due to incorrect mounting, connection or start-up of the positioner.
Î Refer to the Mounting and Operating Instructions EB 8387-5 on how to mount the positioner, perform the electric and pneumatic connections as well as start up the positioner.
Î Observe the warnings and safety instructions written in the Mounting and Operating Instructions EB 8387-5.
Further documentation
The documents listed below contain descriptions of the start-up, functioning and operation ofthe positioner. You can download these documents from the SAMSON website.
Type 3731-5 Positioner
u T 8387-5:
Data sheet
u EB 8387-5: Mounting and operating instructions
u KH 8387-5: Configuration manual
EXPERTplus diagnostics (Type 3731-5 Positioner in firmware version 1.50 and higher)
u T 8389:
Data sheet
u EB 8389:
Operating instructions
EXPERT+ diagnostics (Type 3731-5 Positioner up to firmware version 1.49)
u T 8388:
Data sheet
u EB 8388-5: Operating instructions
NoteIn addition to the positioner documentation, observe the documentation for the pneumatic
actuator, valve and other valve accessories.

SH 8387-5 EN34SH 8387-5 ENContents

11.1
1.2
1.3
1.4

Scope............................................................................................................6General.........................................................................................................6
Use in safety-instrumented systems...................................................................6
Versions and ordering data.............................................................................6Attachment.....................................................................................................62

Technical data (excerpt from EB 8387-5).........................................................73
3.1
3.2

Safety-related functions..................................................................................8Fail-safe action...............................................................................................8
Protection against unauthorized changes to the configuration...........................104Mounting, connection and start-up................................................................1055.1
5.2
5.3

Required conditions......................................................................................10Selection......................................................................................................11Mechanical and pneumatic installation...........................................................11
Electrical installation......................................................................................1266.1
6.2

Proof testing (periodic)..................................................................................13
Visual inspection to avoid systematic failure....................................................13
Function testing.............................................................................................14

7

Maintenance and repair...............................................................................15

8

Safety-related data and certificates...............................................................16SH 8387-5 EN5

Scope1 Scope
1.1 General
The Type 3731-5 Electropneumatic Ex d Positioner is a single-acting positioner for mounting
on pneumatic rotary and linear actuators with spring-return mechanism. The positioner isused to position control valves.

1.2 Use in safety-instrumented systems
Observing the requirements of IEC 61508, the systematic capability of the pilot valve foremergency venting as a component in safety-instrumented systems is given.
Use of the positioner is possible on observing the requirements of IEC 61511 and the required hardware fault tolerance in safety-instrumented systems up to SIL 2 (single device/
HFT = 0) and SIL 3 (redundant configuration/HFT = 1).
The Ex d positioner is regarded as a type A device according to IEC 61508-2 in view of itssafety functions.

1.3 Versions and ordering data
All versions of the Type 3731-5 Positioner are suitable for use in safety-instrumented systems.

1.4 Attachment
The positioner is suitable for the following types of attachment in combination with various
mounting parts:− Direct attachment to SAMSON Type 3277 Linear Actuators− Attachment to linear actuators according to IEC 60534-6 (NAMUR)− Attachment to SAMSON Type 3510 Micro-flow Valve− Attachment to rotary actuators according to VDI/VDE 3845

6SH 8387-5 ENTechnical data (excerpt from EB 8387-5)

2 Technical data (excerpt from EB 8387-5)
Type 3731-5 Positioner with FOUNDATIONTM fieldbus communication
Technical data in test certificates additionally apply to explosion-protected devices.
Bus connection

Fieldbus interface according toPhysical Layer Class
Field unit according toCommunication

IEC 61158-2, bus powered
113 (without explosion protection)
111 (explosion-protected version)
FM 3610 entity and FISCO

Fieldbus

Data transmission conforming to FOUNDATIONTM fieldbus specification
Communication Profile Class: 31 PS, 32 L
Interoperability tested according to Interoperability Test Kit (ITK) 6.2.0

Execution times

AO FB: 30 ms · DI FB: 20 ms · PID: 40 ms

Local

SAMSON SSP interface and serial interface adapter
Software requirements (SSP): TROVIS-VIEW with database module 3731-5

Permissible operating voltage

9 to 32 V DC · Powered by bus line
The limits specified in the examination certificate additionally apply.

Maximum operating current

15 mA

Additional current in case of error

0 mA

SupplyType 3731-521, Type 3731-527: 1.4 to 7 bar (20 to 105 psi)
Type 3731-523: 1.4 to 6 bar (20 to 90 psi)

Supply air

Air quality acc. to Max. particle size and density: Class 4 · Oil content: Class 3
ISO 8573-1 (2004 Moisture and water: Class 3edition)
Pressure dew point: at least 10 K below the lowest ambient temperature to be expected
Signal pressure (output)

0 bar up to supply pressure

Hysteresis≤0.3 %

Sensitivity≤0.1 %

Transit time

Up to 240 s separately adjustable for exhaust and supply by software

Direction of action

Reversible

Air consumption

Independent of supply air approx. < 110 ln/h

Air output
capacity

Actuator (supply)

At Δp = 6 bar: 8.5 mn³/h · At Δp = 1.4 bar: 3.0 mn³/h · KVmax(20 °C) = 0.09

Actuator (exhaust)

At Δp = 6 bar: 14.0 mn³/h · At Δp = 1.4 bar: 4.5 mn³/h · KVmax (20 °C) = 0.15

Permissible ambient temperature

SH 8387-5 EN–40 to +80 °C
The limits in the test certificate additionally apply.

7

Safety-related functions

Type 3731-5 Positioner with FOUNDATIONTM fieldbus communication
Technical data in test certificates additionally apply to explosion-protected devices.
Use in safety-instrumented systems(SIL)
Emergency venting at 0 V

Observing the requirements of IEC 61508, the systematic capability of the pilot
valve for emergency venting as a component in safety-instrumented systems isgiven.
Use is possible on observing the requirements of IEC 61511 and the required
hardware fault tolerance in safety-instrumented systems up to SIL 2 (single device/HFT = 0) and SIL 3 (redundant configuration/HFT = 1).

3 Safety-related functions
Emergency venting over the i/p converter (Fig. 1 path)

In automatic mode, the PD controller (3) compares the valve position to the control signal issued by FOUNDATION™ fieldbus. In case of a system deviation, the activation of the i/p converter is changed so that the actuator (1) is either vented or supplied with air. Fail-safe action
is triggered when the electrical input (terminals marked "IEC 61158-2") is de-energized andthe voltage at the i/p converter drops to 0 V. This causes the actuator to vent.

3.1 Fail-safe action
Fail-safe action is triggered by the i/p converter upon supply air failure. The positioner fullydischarges its pneumatic output to the atmosphere, causing the pneumatic actuator to bevented. As a result, the valve moves to the fail-safe position. The fail-safe position depends
on how the springs are arranged in the pneumatic actuator (air-to-close or air-to-open).
When the air supply fails, all positioner functions, except for open/closed-loop control, remain active (including diagnostics and communication).
Note
The pneumatic output of the positioner can also be vented to the atmosphere over thesoftware, e.g. by entering a suitable set point. This procedure is not a safety-instrumentedfunction.

8SH 8387-5 ENSafety-related functions

2220

SerialInterface

2316%mm%mm

IEC 61158-2

S4519w

PD

17x23G6981y712345678Control valve
Travel sensor
PD controller
Interface module (IEC 61158-2)
Microcontroller
i/p converter
Air booster
Pressure regulator

x916171920
2223

Flow regulator
Display
Actuation of forced venting (optional)
D/A converter
Serial interface (SSP)
Rotary pushbutton
Binary input (optional)

Fig. 1: Functional diagram of the positioner

SH 8387-5 EN

9Mounting, connection and start-up

3.2 Protection against unauthorized changes to the configuration
A change to the configuration cannot affect the safety function nor cause it to be deactivated.

4 Mounting, connection and start-up
Refer to Mounting and Operating Instructions u EB 8387-5 on how to mount, perform theelectric and pneumatic connections as well as start up the positioner.
Only use the specified original mounting parts and accessories.

GuOption

Option

A B C

A B C

A B C

L/+ N/_
0...40 V DC
0...28 V AC

Forced venting+__IEC 61158-2

Option+Signal

Version 1 or version 2Binary input

Fig. 2: Electrical connection

5 Required conditions! WARNING
Risk of malfunction due to incorrect selection or wrong installation and operating conditions.
Î Only use control valves in safety-instrumented systems if the necessary conditions in theplant are fulfilled. The same applies to the mounted positioner.

10SH 8387-5 EN

Required conditions

5.1 Selection
Î The required transit times of the control valve are observed.
The transit times to be implemented are determined by the process engineering requirements.
TipThe minimum OPEN and CLOSE transit times can be read in Codes 40 and 41 after thepositioner has been initialized.
Î The positioner is suitable for the prevailing ambient temperature.
VersionsTemperature range

All–40 to +80 °C

The temperature limits for the explosion-protected devices may be further restricted by the limits specified in the test certificates.

Î The temperature limits are observed.

5.2 Mechanical and pneumatic installation
Î The positioner is mounted properly as described in the mounting and operating instructions and connected to the air supply.
Tip
Error codes 50 to 58 indicate incorrect attachment. For safety-instrumented systems, werecommend assigning the 'Failure' status to these errors to quickly recognize them when
they occur (indicated by on the display).
Î The supply pressure does not exceed the maximum limit specified below.
–

Type 3731-521 and Type 3731-527: 7 bar–

Type 3731-523: 6 bar

Î The pneumatic air supply meets the instrument air specifications.
Particle size and quantity

Oil content

Moisture and water

Class 4

Class 3

Class 3≤ 5 µm and 1000/m³≤ 1 mg/m³

Pressure dew point: at least 10 K below thelowest ambient temperature to be expected

SH 8387-5 EN

11

Required conditions

Tip
We recommend installing a supply pressure regulator/filter upstream of the device. For
example, the SAMSON Type 4708 Supply Pressure Regulator with 5 µm filter cartridge
can be used.
Î The supply air line has a minimum inside diameter of 4 mm.
Select the cross section and length of the line to ensure that the supply pressure at the positioner on supplying air to the actuator does not fall below the minimum limit.
Î The positioner is mounted as prescribed.
Î The vent opening at the back of the positioner remains open when the positioner is installed on site.

5.3 Electrical installation
Î The positioner is connected to the electric power supply properly as described in themounting and operating instructions.
Î Only cables whose outside diameters are suitable for the cable glands are used.
Î When the positioner is connected according to the type of protection Ex d, cable entries
or conduit systems are used that comply with EN 60079-1 Explosive Atmospheres –Part 1: Equipment Protection by Flameproof Enclosures "d", Clauses 13.1 and 13.2 andfor which a separate test certificate is available.
Î When the positioner is connected according to the type of protection Ex e, cable entries
and blanking plugs are used, which are certified according to type of protection Ex e(ATEX) and have a separate test certificate.
Î The cable glands and cover screws are fastened tightly to ensure that the degree of protection is met.
Î The installation requirements for the applicable explosion protection measures are observed.
Î The special conditions specified in the explosion protection certificates are observed.

12SH 8387-5 EN

Proof testing (periodic)

6 Proof testing (periodic)
The proof test interval and the extent of testing lie within the operator's responsibility. The
operator must draw up a test plan, in which the proof tests and the interval between them
are specified. We recommend summarizing the requirements of the proof test in a checklist.
! WARNING
Risk of dangerous failure due to malfunction in the event of emergency (actuator is notvented or the valve does not move to the fail-safe position).
Î Only use devices in safety-instrumented systems that have passed the proof test according
to the test plan drawn up by the operator.
Regularly check the safety-instrumented function of the entire SIS loop. The test intervals are
determined, for example on calculating each single SIS loop in a plant (PFDavg).

6.1 Visual inspection to avoid systematic failure
To avoid systematic failure, inspect the positioner regularly. The frequency and the scope of
the inspection lie within the operator's responsibility. Take application-specific influences into
account, such as:− Dirt blocking the pneumatic connections− Corrosion (destruction primarily of metals due to chemical and physical processes)− Material fatigue− Aging (damage caused to organic materials, e.g. plastics or elastomers, by exposure tolight and heat)− Chemical attack (organic materials, e.g. plastics or elastomer, which swell, leach out or
decompose due to exposure to chemicals)! NOTICE
Risk of malfunction due to the use of unauthorized parts.
Î Only use original parts to replace worn parts.

SH 8387-5 EN13

Proof testing (periodic)

6.2 Function testing
Regularly check the safety function according to the test plan drawn up by the operator.
NoteRecord any positioner faults and e-mail (aftersalesservice@samsongroup.com) them toSAMSON.
Emergency venting by applying a 0 V signal to terminals marked "IEC 61158-2"
1. Supply the positioner with air within the permissible supply pressure range (max. 7 barfor Type 3731-521 and Type 3731-527 or 6 bar for Type 3731-523) which allows thevalve to move to the maximum travel/angle of rotation.
2. Connect the two-wire bus line to the bus connection terminals (marked "IEC 61158-2"),
ensuring that the permissible supply voltage between 9 to 32 V DC (power by the busline) is observed.
3. Switch the positioner to automatic mode (if it has not already been done).
4. Set the input signal over FOUNDATION™ fieldbus (terminals marked "IEC 61158-2) insuch a way that the valve moves to the operating position. Check whether the valve
moves to this position.
Tip
The travel/angle of rotation in automatic mode can be read at the positioner in Code 0.
5. Disconnect the supply voltage to achieve a supply voltage of 0 V at the bus connection
terminals (marked "IEC 61158-2"). This must cause the valve to move to its fail-safe
position.
6. Check whether the actuator is fully vented within the demanded time.
7. Set the input signal over FOUNDATION™ fieldbus (terminals marked "IEC 61158-2") insuch a way that the valve moves to the approx. 50 % of its travel/angle of rotation.
Check whether the valve moved to this position.
8. Disconnect the supply voltage to achieve a supply voltage of 0 V at the bus connection
terminals (marked "IEC 61158-2"). This must cause the valve to move to its fail-safe position.
9. Check whether the actuator is fully vented within the demanded time.

14SH 8387-5 EN

Maintenance and repair

Tip
Connect a pressure gauge to check that the actuator has completely vented.
Proof test
A full stroke test must be performed as the proof test. The following value can be used for
Proof Test Coverage to calculate PFDavg:
PTC (Proof Test Coverage) = 92 % for a proof test

7 Maintenance and repair
Only perform the work on the positioner described in u EB 8387-5.
! NOTICE
Safety function impaired due to incorrect repair.
Î Only allow trained staff to perform service and repair work.
For devices operated in the low demand mode, a useful lifetime of 11 years (plus 1.5 yearsstorage time) is confirmed by TÜV Rheinland® from the date of manufacture while taking into
account the specific conditions of use specified in the Safety Manual and the Mounting andOperating Instructions.
The results of the proof test must be assessed and the maintenance scheduled based on it. In
particular, after changes (e.g. signs of aging in elastomers, changed switching times or leakage etc.), it is essential that the manufacturer performs maintenance or repair work on thedevice.
MTC (Maintenance Coverage) > 99 %SH 8387-5 EN15

Safety-related data and certificates

8 Safety-related data and certificates
PSTC (Partial Stroke Test Coverage)

68 %PTC (Proof Test Coverage)

92 %MTC (Maintenance Coverage)>99 %Further safety-related data are listed in the following certificate.

16SH 8387-5 EN

SH 8387-5 EN

17

18

SH 8387-5 EN

SH 8387-5 EN

19

SAMSON AKTIENGESELLSCHAFT
Weismüllerstraße 3 · 60314 Frankfurt am Main, GermanyPhone: +49 69 4009-0 · Fax: +49 69 4009-1507
samson@samsongroup.com · www.samsongroup.com

2020-08-24 · English

SH 8387-5 EN