Samson 4765 Service manual

Translation of original instructions
EB 8359-1 EN
Edition March 2020
Type4765 Pneumatic Positioner

Note on these mounting and operating instructions
These mounting and operating instructions assist you in mounting and operating the device
safely. The instructions are binding for handling SAMSON devices.
ÎFor the safe and proper use of these instructions, read them carefully and keep them for
later reference.
ÎIf you have any questions about these instructions, contact SAMSON‘s After-sales Service
([e-mail]).
The mounting and operating instructions for the devices are included in
the scope of delivery. The latest documentation is available on our website
at www.samsongroup.com > Service & Support > Downloads >
Documentation.
Denition of signal words
Hazardous situations which, if not avoided,
will result in death or serious injury
Hazardous situations which, if not avoided,
could result in death or serious injury
Property damage message or malfunction
Additional information
Recommended action
DANGER
!
WARNING
!
NOTICE
!
Note
Tip
2 EB 8359-1 EN

Contents
EB 8359-1 EN 3
1 Safety instructions and measures ...................................................................5
1.1 Notes on possible property damage................................................................7
2 Markings on the device .................................................................................7
2.1 Article code...................................................................................................7
3 Design and principle of operation ..................................................................8
3.1 Accessories, mounting parts and conversion kits.............................................10
3.2 Technical data .............................................................................................11
3.3 Dimensions in mm........................................................................................12
4 Measures for preparation............................................................................13
4.1 Unpacking ..................................................................................................13
4.2 Transporting ................................................................................................13
4.3 Storage.......................................................................................................13
5 Mounting and start-up.................................................................................14
5.1 Attachment to valve with cast yoke ................................................................14
5.2 Attachment to valve with rod-type yoke..........................................................14
5.3 Housing cover .............................................................................................14
5.4 Pneumatic connections..................................................................................16
5.4.1 Pressure gauges...........................................................................................16
5.4.2 Supply pressure ...........................................................................................16
6 Operating the positioner..............................................................................17
6.1 Assignment of the positioner and actuator......................................................17
6.1.1 Determining and changing the operating direction .........................................18
6.2 Starting point and reference variable.............................................................20
6.3 Adjustment after mounting the positioner on the valve.....................................20
6.3.1 Setting the air delivery (volume restriction Q) and proportional band Xp..........20
6.3.2 Setting for actuator with fail-safe action “stem extends”...................................22
6.3.3 Setting for actuator version “stem retracts” .....................................................22
6.4 Exchanging the range spring........................................................................23
7 Upgrading the pneumatic positioner ............................................................24
8 Servicing.....................................................................................................26
8.1 Preparation for return shipment.....................................................................26

Contents
4 EB 8359-1 EN
9 Decommissioning and removal ....................................................................27
9.1 Decommissioning.........................................................................................27
9.2 Removing the positioner ...............................................................................27
9.3 Disposal......................................................................................................27
10 Annex.........................................................................................................28
10.1 After-sales service........................................................................................28

EB 8359-1 EN 5
Safety instructions and measures
1 Safety instructions and measures
Intended use
The SAMSON Type4765 Positioner is mounted on pneumatic control valves and used to
assign the valve position to the control signal. The device is designed to operate under
exactly dened conditions (e.g. operating pressure, temperature). Therefore, operators must
ensure that the positioner is only used in applications where the operating conditions
correspond to the technical data. In case operators intend to use the positioner in other
applications or conditions than specied, contact SAMSON.
SAMSON does not assume any liability for damage resulting from the failure to use the
device for its intended purpose or for damage caused by external forces or any other
external factors.
ÎRefer to the technical data for limits and elds of application as well as possible uses.
Reasonably foreseeable misuse
The Type4765 Positioner is not suitable for the following applications:
−Use outside the limits dened during sizing and by the technical data
Furthermore, the following activities do not comply with the intended use:
−Use of non-original spare parts
−Performing maintenance activities not specied by SAMSON
Qualications of operating personnel
The positioner must be mounted, started up and serviced by fully trained and qualied
personnel only; the accepted industry codes and practices must be observed. According to
these mounting and operating instructions, trained personnel refers to individuals who are
able to judge the work they are assigned to and recognize possible hazards due to their
specialized training, their knowledge and experience as well as their knowledge of the
applicable standards.
Personal protective equipment
No personal protective equipment is required for the direct handling of the positioner. Work
on the control valve may be necessary when mounting or removing the device.
ÎObserve the requirements for personal protective equipment specied in the valve docu-
mentation.
ÎCheck with the plant operator for details on further protective equipment.

6 EB 8359-1 EN
Safety instructions and measures
Revisions and other modications
Revisions, conversions or other modications of the product are not authorized by SAMSON.
They are performed at the user's own risk and may lead to safety hazards, for example. Fur-
thermore, the product may no longer meet the requirements for its intended use.
Safety features
Upon failure of the air supply, the positioner vents the actuator, causing the valve to move to
the fail-safe position determined by the actuator.
Warning against residual hazards
The positioner has direct inuence on the control valve. To avoid personal injury or property
damage, plant operators and operating personnel must prevent hazards that could be
caused in the control valve by the process medium, the operating pressure, the signal
pressure or by moving parts by taking appropriate precautions. Plant operators and
operating personnel must observe all hazard statements, warning and caution notes in these
mounting and operating instructions, especially for installation, start-up and service work.
If inadmissible motions or forces are produced in the pneumatic actuator as a result of the
supply pressure, it must be restricted using a suitable supply pressure reducing station.
Responsibilities of the operator
The operator is responsible for proper operation and compliance with the safety regulations.
Operators are obliged to provide these mounting and operating instructions to the operating
personnel and to instruct them in proper operation. Furthermore, the operator must ensure
that operating personnel or third persons are not exposed to any danger.
Responsibilities of operating personnel
Operating personnel must read and understand these mounting and operating instructions as
well as the specied hazard statements, warning and caution notes. Furthermore, the operat-
ing personnel must be familiar with the applicable health, safety and accident prevention
regulations and comply with them.
Referenced documentation
The following documents apply in addition to these mounting and operating instructions:
−The mounting and operating instructions of the components on which the positioner is
mounted (valve, actuator, valve accessories etc.).

EB 8359-1 EN 7
Markings on the device
1.1 Notes on possible property damage
NOTICE
!
Risk of malfunction due to failure to comply with air quality requirements.
ÎOnly use supply air that is dry and free of oil and dust.
ÎRead the maintenance instructions for upstream pressure reducing stations.
ÎBlow through all air pipes and hoses thoroughly before connecting them.
2 Markings on the device
2.1 Article code
Pneumatic positioner Type4765- 0 1 x0 0 x1x0000
Spring
Spring 1, travel = 15 mm 1
Spring 2, travel = 30 mm, split range 15 mm 2
Spring 3, travel = 60 mm, split range 30 mm 3
Pneumatic connections
ISO228/1G¼ 1
¼-18NPT 3
Temperature range
Standard 0
Low temperature down to –50 °C 1

8 EB 8359-1 EN
Design and principle of operation
3 Design and principle of oper-
ation
The pneumatic positioner is used to assign
the valve position (controlled variable) to the
input signal (reference variable). The posi-
tioners compare the control signal of a con-
trol system to the travel of the control valve
and issues a signal pressure (output variable)
for the pneumatic actuator.
The positioner consists of the lever with shaft
and range spring, the measuring diaphragm
and the pneumatic control system with noz-
zle, apper plate and booster. In addition, a
pressure gauge can optionally be attached
for the control signal (input) and the signal
pressure (output signal).
The positioner operates according to the
force-balance principle. In this way, the
motion of the actuator stem or the plug stem
(controlled variable x) is transmitted to the
lever (1) and the range spring (6) over the
plate (20). This action twists the range spring
and varies its spring force.
The reference variable, i.e. the control signal
(pe) of the upstream controller, produces a
force which acts on the surface of the mea-
suring diaphragm (8) and is compared to
the force of the range spring (6). At the same
time, the motion of the measuring dia-
phragm is transferred to the apper plate
(10.2) over the feeler pin (9.1) and the noz-
zle (10.1) releases pressure. The supply air is
fed to the booster (12) and ows through the
Xp restriction (13) and the nozzle (10.1) and
hits the apper plate (10.2).
Any change in the control signal peor the
valve position causes the pressure to change
upstream or downstream of the booster. The
air controlled by the booster (signal pressure
pst) ows through the volume restriction (14)
to the pneumatic actuator, causing the plug
stem to move to a position corresponding to
the reference variable.
The adjustable restrictions (13 and 14) are
used to optimize the positioner control loop.
The range spring (6), which can be ex-
changed, is assigned to both the rated valve
travel and the span of the reference variable.
Legend for Fig.1 and Fig.2
1 Lever for valve travel
1.1 Shaft
2Pin
2.1 Nut
3 Sleeve
4 Zero point adjustment
5 Fastening screw
6 Range spring
6.1 Bracket
7 Fastening screw
8 Measuring diaphragm
9 Diaphragm lever
9.1 Feeler pin
10 Nozzle block
10.1 Nozzle
10.2 Flapper plate
11 Cover plate
12 Booster
13 Xp restriction
14 Volume restriction Q
15 Hole for fastening screw
20 Plate

EB 8359-1 EN 9
Design and principle of operation
10.21314
3
1
15
7
8
45 6.1 6
Output
38
Supply 9Input
Fig.1: Positioner (opened)
1.1 122.1 20
4
6
8
9
9.1
10.2
10
10.1
11
pst
Output 38
Supply 9 pe
Input
6
8
9
9.1
12.2
10.1
10
12
14
13
Travel
Arrangement of nozzle/
apper plate for reverse
<> operating direction
Fig.2: Functional diagram

10 EB 8359-1 EN
Design and principle of operation
3.1 Accessories, mounting parts and conversion kits
Accessories – Mounting parts Ordering number
Range spring 1
Range spring 2
Range spring 3
Lever I
Lever extension
Pressure gauge attachment, up to device index .02
Pressure gauge attachment, device index .03 and higher
Pressure gauge attachment (copper-free), up to device index .02
Pressure gauge attachment (copper-free), device index .03 and higher
1190-0736
1190-0737
1190-0738
1690-6469
1400-6716
1400-6718
1402-0938
1400-6719
1402-0939
Mounting kit for valves with cast yoke according to NAMUR
Valves with rod-type yoke according to NAMUR for 18 to 35mm rod diameter
1400-5745
1400-5745 and
1400-5342
Assortment of spare parts including gaskets and diaphragms 1400-6792
Assortment of spare parts including gaskets, diaphragms and pneumatic parts
(for devices with device index .02 and higher)
1402-0040
Upgrade to degree of protection IP65:
Venting over check valve 1790-7408
Required input signal
(reference variable) Required i/p module
Type (order no.)
Additional conversion kit
(device index .03 and higher)
Order no.
4 to 20 mA
0 to 20 mA
1 to 5 mA
6109-0010
6112-002110
6112-003110
1400-6797
1400-6798
1400-6798

EB 8359-1 EN 11
Design and principle of operation
3.2 Technical data
Controlled variable (travel
range) 7.5 to 60mm, with lever extension: 7.5 to 90mm
Reference variable 0.2 to 1bar (3 to 15psi)
Split-range 0 to 50% or 50 to
100%
reference variable span
(up to 50mm travel)
0.2 to 0.6bar (3 to 9psi) and
0.6 to 1bar (9 to 15psi)
Range spring See Table 1 on page21 for selection
Supply Supply air: 1.4 to 6 bar (20 to 90 psi)
Air quality acc. to ISO8573-1: max. particle size and density:
Class 4 · Oil content: Class 3 · Pressure dew point: Class 3
Signal pressure pst (output) Max. 0 to 6.0bar (0 to 90psi)
Characteristic Linear characteristic
Deviation from terminal-based conformity ≤1.5%
Hysteresis < 0.5%
Sensitivity < 0.1%
Direction of action Reversible
Proportional band Xp (at 1.4bar
supply air)
1 to 3.0% with spring 1
1 to 2.0% with spring 2
1 to 1.5% with spring 3
Air consumption in steady state,
Xp = 1%
With 1.4bar supply air: 0.13 mn³/h
With 6bar supply air: 0.33 mn³/h
Air output At Δp = 1.4bar: 3.0mn³/h · At Δp = 6bar: 8.5mn³/h
Transit time with Type3271
Actuator, “stem extends” 240
 cm² ≤ 1.8  s · 350  cm² ≤ 2.5  s · 700  cm² ≤ 10  s
Perm. ambient temperature1) –20 to +80
 °C
Inuences Temperature: < 0.02%/1K
Supply: < 0.20%/0.1bar
Variable position when turned by 180°: < 3.50%
Degree of protection IP54 · Venting over check valve (1790-7408): IP65
Compliance
Weight Approx. 1.1kg
Materials
Housing Die-cast aluminum, chromated and plastic coated
External parts Stainless steel
1) Extended temperature range on request

12 EB 8359-1 EN
Design and principle of operation
3.3 Dimensions in mm
Output
Input
38
Supply
9
157
114.5
121
131.5
99
27.7 44
79
15
69
28 37
l
G
1
/
8
tapped hole in housing
with G threaded connection or
1
/
8
NPT
In housing with NPT threaded
connection
Useable lever length I: 40 to 127mm (with lever extension 40 to 200mm)
Pneumatic connections: ISO-228/1-G¼ or ¼-18NPT

EB 8359-1 EN 13
Measures for preparation
4 Measures for preparation
After receiving the shipment, proceed as fol-
lows:
1. Check the scope of delivery. Compare
the shipment received with the delivery
note.
2. Check the shipment for transportation
damage. Report any transportation
damage.
4.1 Unpacking
Risk of positioner damage due to foreign
particles entering it.
Do not remove the packaging and protective
lm/protective caps until immediately before
mounting and start-up.
1. Remove the packaging from the position-
er.
2. Dispose of the packaging in accordance
with the valid regulations.
4.2 Transporting
−Protect the positioner against external in-
uences (e.g. impact).
−Protect the positioner against moisture
and dirt.
−Observe transport temperature depend-
ing on the permissible ambient tempera-
ture (see technical data in section3.2).
4.3 Storage
Risk of positioner damage due to improper
storage.
− Observe the storage instructions.
−Avoid long storage times.
−Contact SAMSON in case of different
storage conditions or long storage periods.
Storage instructions
−Protect the positioner against external in-
uences (e.g. impact, shocks, vibration).
−Do not damage the corrosion protection
(coating).
−Protect the positioner against moisture
and dirt. In damp spaces, prevent con-
densation. If necessary, use a drying
agent or heating.
−Observe storage temperature depending
on the permissible ambient temperature
(see technical data in section3.2).
−Store the positioner with the cover
closed.
−Seal the pneumatic connections.
NOTICE
!
NOTICE
!

14 EB 8359-1 EN
Mounting and start-up
5 Mounting and start-up
To attach the positioner to valves with cast
yokes), mounting parts (order no. 1400-
5745) are used. For valves with rod-type
yokes (pillars), the mounting kit (order no.
1400-5745) and additionally the mounting
kit (order no. 1400-5342) are necessary
(see page10).
Since the positioner can be attached on ei-
ther side of the valve, the physical location
(left or right attachment) should be deter-
mined before actual attachment.
ÎSee Fig.5 to Fig.8 on page17.
5.1 Attachment to valve with
cast yoke
1. Fasten the plate (20) to the stem connec-
tor (22) of the valve using the screws
(21).
2. Unscrew the positioner cover and secure
the positioner to the valve yoke using the
fastening screw (15). Make sure that the
pin (2) is inserted through the wire strap
and, as a result, clamped against the
plate (20).
5.2 Attachment to valve with
rod-type yoke
1. Fasten the plate (20), off-centered, to the
travel indicator (24) of the plug stem (23)
using the screws (21).
2. Place both the support (28) and the
clamping plate (26) on the rod (27) and
lightly fasten. Move the support until both
the center of the plate (20) and the sup-
port (28) are aligned when the valve is
at half of the valve travel.
3. Fasten tight the support and the clamp-
ing plate.
4. Mount the positioner to the support using
the fastening screw (15). Make sure that
the pin (2) is inserted through the wire
strap and, as a result, clamped against
the plate (20).
5.3 Housing cover
After attaching the positioner, make sure that
the vent plug of the housing cover faces
downward when the valve is installed.
Legend for Fig.3 and Fig.4
1 Lever
2Pin
2.1 Nut
15 Fastening screw
20 Plate
21 Screw
22 Stem connector
23 Plug stem
24 Travel indicator
26 Clamping plate
27 Rod (pillar)
28 Support

EB 8359-1 EN 15
Mounting and start-up
15 1202 2.1 21 22 23
Fig.3: Attachment to valves with cast yokes (NAMUR rib)
15 128272620 2.1 2212423
Fig.4: Attachment to valves with rod-type yokes

16 EB 8359-1 EN
Mounting and start-up
5.4 Pneumatic connections
The pneumatic connections are optionally
designed as a bore with NPT or ISO288/1-
G thread.
Customary ttings for metal or copper tubing
or plastic hoses can be used.
Risk of malfunction due to failure to comply
with air quality requirements.
− Only use supply air that is dry and free of
oil and dust.
−Read the maintenance instructions for up-
stream pressure reducing stations.
−Blow through all air pipes and hoses thor-
oughly before connecting them.
5.4.1 Pressure gauges
To monitor the positioner, we recommend in-
stalling pressure gauges for the supply air
and signal pressure. The required parts are
listed on page10.
5.4.2 Supply pressure
The required supply air pressure depends on
the bench range and the actuator's direction
of action (fail-safe action).
The bench range is written on the nameplate
either as the bench range or signal pressure
range. The operating direction is marked FA
or FE or by a symbol.
Actuator stem extends (FA)
Fail-close
(for globe and angle valves)
Required supply pressure =
Upper bench range value + 0.2 bar,
minimum 1.4 bar
Actuator stem retracts (FE)
Fail-open
(for globe and angle valves)
For tight-closing valves, the maximum signal
pressure pstmax is roughly estimated as fol-
lows:
pstmax = F + d² · π · ∆p [bar]
4 · A
d = Seat diameter [cm]
∆p = Differential pressure across the valve
[bar]
A = Actuator area [cm²]
F = Upper bench range value of
actuator [bar]
If there are no specications, calculate as
follows:
Required supply pressure =
Upper bench range value + 1bar
The positioner output pressure is routed to
the top or bottom diaphragm case of the
actuator as shown in Fig.5 to Fig.8.
NOTICE
!

EB 8359-1 EN 17
Operating the positioner
6 Operating the positioner
6.1 Assignment of the posi-
tioner and actuator
Arrangement of the actuator, the mounting
position of the positioner, the reference vari-
able and the operating direction:
ÎSee Fig.5 to Fig.8
When any subsequent changes are made,
e.g. reversing the operating direction of the
positioner control loop or changing the actu-
ator fail-safe action from “actuator stem ex-
tends” to “actuator stem retracts” or vice ver-
sa, the positioner's mounting position must
be changed accordingly.
Actuator stem extends (FA)
1
20
pst
w
1
20
pst
w
Lever (1) located at top of plate (20) Lever (1) located at bottom of plate (20)
Fig.5: Operating direction << Left attachment Fig.6: Operating direction <> Right
attachment
Actuator stem retracts (FE)
p
st
w
p
st
w
Fig.7: Operating direction << Right
attachment
Fig.8: Operating direction <> Left attachment

18 EB 8359-1 EN
Operating the positioner
6.1.1 Determining and
changing the operating
direction
For an increasing input signal (reference
variable), the signal pressure pst can either
be increasing (direct action <<) or decreas-
ing (reverse action <>).
Similarly, as the reference variable decreas-
es, the signal pressure can either decrease
(direct action <<) or increase (reverse action
<>).
On the apper plate, the operating direction
is indicated by symbols (direct <<, reverse
<>). Depending on the position of the ap-
per plate, the adjusted operating direction
and the associated symbol is visible.
If the required operating direction does not
correspond to the visible symbol or if the op-
erating direction is to be changed, proceed
as follows:
1. Unscrew both screws on the cover plate
and lift off the nozzle block along with
the cover plate.
2. Reinstall the nozzle block turned by 180°
together with the cover plate and refas-
ten.
Make sure that the nozzle block and apper
plate are correctly located above or below
the feeler pin as shown in Fig.10.
If the operating direction is to be changed
after the initially determined arrangement of
positioner and actuator, note that the posi-
tioner must be mounted in a different loca-
tion and the nozzle block must be turned.
Make sure the location of the lever (1) and
the plate (20), "lever located at top of plate"
or "lever located at bottom of plate" is cor-
rect (Fig.5 to Fig.8).

EB 8359-1 EN 19
Operating the positioner
Fig.10: Position of nozzle block, cover plate removed
Fig.11: Normal operation Fig.12: Split-range operation, two valves operating in
opposing directions
Operating direction increasing/increasing (direct <<)
feeler pin on top of apper plate
Operating direction increasing/decreasing
(reverse <>)
apper plate on top of feeler pin
Range spring
Feeler pin
Cover plate
Nozzle block
Marking Flapper plate
Reference variable
Input signal
Travel
Dead band
Valve 2 Valve 1
Travel

20 EB 8359-1 EN
Operating the positioner
6.2 Starting point and refer-
ence variable
The attached lever and the installed range
spring of the positioner are assigned to the
values of rated valve travel and the reference
variable (input signal) as in Table 1.
In normal operation, the reference variable
span is 100% = 0.8bar. A smaller span of,
for example 50% = 0.4bar is only required
for split-range operation (Fig.12).
The span can be changed by exchanging the
range spring (section6.4).
On making adjustments to the positioner, the
travel must be adapted to the reference vari-
able and vice versa.
With a reference variable, for example 0.2
to 1bar, the valve must move through its en-
tire travel range from 0 to 100%.
The starting point then is 0.2bar and the up-
per range value 1bar.
In split-range operation, the controller output
signal is used to control two control valves,
dividing it such that the valves move through
their entire travel range at half the input sig-
nal range each (e.g. rst valve set to 0.2 to
0.6bar, second valve set to 0.6 to 1bar). To
avoid overlapping, allow for a dead band of
0.05bar as shown in Fig.12.
The starting point (zero) is adjusted at the
screw (4); the reference variable span, i.e.
the upper range value, is adjusted at the pin
(2).
6.3 Adjustment after mounting
the positioner on the valve
Connect the control signal input to a com-
pressed air source of max. 1.5bar using a
remote adjuster and a pressure gauge.
Connect the supply air to the supply input
(supply 9).
6.3.1 Setting the air delivery
(volume restriction Q) and
proportional band Xp
1. Close the volume restriction (14) as far
as the required positioning speed per-
mits.
Check the positioning speed by pushing
the range spring (6) as far it will go.
2. Adjust the reference variable at the input
to approx. 50% of its range. Then, turn
the zero adjustment screw (4) until the
valve is at approximately 50% valve
travel.
On setting the Xp restriction, observe the re-
lationship with the supply pressure as indi-
cated in Fig.9. The preset value of Xp should
be approximately 3%.
3. Check the plug stem's tendency to oscil-
late by pressing the range spring (6)
briey as far as it will go.
The Xp value is to be adjusted to be as
small as possible, without considerable
overshooting occurring.
Additional points that apply concerning
adjustment:
ÎAlways adjust the Xp restriction before
setting the starting point.