Samson 4765 Service manual

Mounting and
Operating Instructions
EB 8359-1 EN
Edition April 2014
Type 4765 Pneumatic Positioner
Type 4765 Pneumatic Positioner

Denition of signal words
DANGER!
Hazardous situations which, if not
avoided, will result in death or seri-
ous injury
WARNING!
Hazardous situations which, if not
avoided, could result in death or seri-
ous injury
NOTICE
Property damage message or mal-
function
Note:
Additional information
Tip:
Recommended action

2 EB 8359-1 EN

Contents
EB 8359-1 EN 3
1 General safety instructions.............................................................................5
2 Article code...................................................................................................6
3 Technical data ...............................................................................................7
4 Design and principle of operation ..................................................................8
5 Attachment .................................................................................................10
5.1 Attachment to valve with cast yoke ................................................................10
5.2 Attachment to valve with rod-type yoke..........................................................10
5.3 Housing cover .............................................................................................10
6 Pneumatic connections.................................................................................12
6.1 Pressure gauge ............................................................................................12
6.2 Supply pressure ...........................................................................................12
7 Operation...................................................................................................13
7.1 Assignment of the positioner and the actuator ................................................13
7.1.1 Determining and changing the operating direction .........................................14
7.2 Starting point and reference variable.............................................................16
7.3 Adjustment after mounting the positioner on the valve.....................................16
7.3.1 Setting the air delivery (volume restriction Q) and proportional band Xp..........16
7.3.2 Setting for actuator with fail-safe action “stem extends”...................................18
7.3.3 Setting for actuator with fail-safe action “stem retracts” ...................................18
7.4 Exchanging the range spring........................................................................19
8 Upgrading the pneumatic positioner ............................................................20
9 Accessories, mounting parts and conversion kits...........................................22
10 Dimensions in mm.......................................................................................23

EB 8359-1 EN 5
General safety instructions
1 General safety instructions
For your own safety, follow these instructions concerning the mounting, start-up and opera-
tion of the positioner:
−The positioner is to be mounted, started up or operated only by trained and experienced
personnel familiar with the product. According to these mounting and operating instruc-
tions, trained personnel refers to individuals who are able to judge the work they are as-
signed to and recognize possible dangers due to their specialized training, their knowl-
edge and experience as well as their knowledge of the applicable standards.
−Any hazards that could be caused in the valve by the process medium and the operating
pressure or by moving parts are to be prevented by taking appropriate precautions.
−If inadmissible motions or forces are produced in the pneumatic actuator as a result of
the supply pressure level, it must be restricted using a suitable supply pressure reducing
station.
To avoid damage to any equipment, the following also applies:
−Proper shipping and storage are assumed.
Note:
Devices with a CE marking fulll the requirements of the Directives 2014/34/EU and
2014/30/EU.
The Declaration of Conformity is available on request.


6 EB 8359-1 EN
Article code
2 Article code
Pneumatic positioner Type 4765- 0 1 x 0 0 x 1 x x x x 0
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
Special version
Without 0 0 0
For oxygen 1) 016
1) Special version suitable for oxygen up to maximum +60°C
(according to AIR LIQUIDE test report no. 2014/R 171a1)

EB 8359-1 EN 7
Technical data
3 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17 for selection
Supply air 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 characteristic according
to terminal point method: ≤ 1.5%
Hysteresis < 0.5%
Sensitivity < 0.1%
Operating direction 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
Permissible ambient temperature1) –20 to 80°C (special version for oxygen: up to max. +60°C)
Inuences Temperature: < 0.02%/1K
Supply air: < 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

8 EB 8359-1 EN
Design and principle of operation
4 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-
tioner compares the control signal issued by
a control 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 mo-
tion 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
Fig.1: Positioner (opened)
1.1 122.1 20
4
6
8
9
9.1
10.2
10
10.1
11
pst
Output 36
Supply 9 pe
Input
27
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
Attachment
5 Attachment
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22).
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13.
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 11
Attachment
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

12 EB 8359-1 EN
Pneumatic connections
6 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.
NOTICE
Risk of malfunction due to failure to
comply with required air quality.
−Only use supply air that is dry and
free of oil and dust.
−Read the maintenance instructions
for upstream pressure reducing sta-
tions.
−Blow through all air pipes and hos-
es thoroughly before connecting
them.
6.1 Pressure gauge
To monitor the positioner, we recommend in-
stalling pressure gauges for the supply air
and signal pressure. The required parts are
listed on page22.
6.2 Supply pressure
The required supply air pressure depends on
the bench range and the actuator's operat-
ing direction (fail-safe action).
The bench range is written on the nameplate
either as the spring 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 diaphragm 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 ac-
tuator as shown in Fig.5 to Fig.8.

EB 8359-1 EN 13
Operation
7 Operation
7.1 Assignment of the posi-
tioner and the 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) on top of plate (20) Plate (20) on top of lever (1)
Fig.5: Operating direction << Left attachment Fig.6: Operating direction <> Right attach-
ment
Actuator stem retracts (FE)
p
st
w
p
st
w
Fig.7: Operating direction << Right attach-
ment
Fig.8: Operating direction <> Left attachment

14 EB 8359-1 EN
Operation
7.1.1 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 become visible.
If the required operating direction does not
correspond to the visible symbol, or if the
operating direction is to be changed, pro-
ceed 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 180° to-
gether with the cover plate, and refasten.
Make sure that the nozzle block and apper
plate are correctly located above or below
the feeler pin as shown in Fig.9.
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 on top of plate" or re-
versed "plate on top of lever" is correct
(Fig.5 to Fig.8).

EB 8359-1 EN 15
Operation
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
Fig.9: Position of nozzle block, cover plate removed
Reference variable
Input signal
Travel
Dead band
Valve 2 Valve 1
Travel
Fig.10: Normal operation Fig.11: Split-range operation, two valves operating in
opposing directions

16 EB 8359-1 EN
Operation
7.2 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.11).
The span can be changed by exchanging the
range spring (section7.4).
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.11.
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).
7.3 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).
7.3.1 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 air pressure as in-
dicated in Fig.12. 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 ad-
justment:
ÎAlways adjust the Xp restriction before
setting the starting point.

EB 8359-1 EN 17
Operation
Table 1: Range springs
Rated travel [mm] Min./max. travel [mm] Reference variable (input signal) Range spring
Standard travels for SAMSON valves with lever l (40 to 127mm in length)
15 7.5 to 15 100%
50%
1
2
30 14 to 32 100%
50%
2
3
60 30 to 70 100% 3
Further travel ranges with lever l and lever extension (40 to 200mm in length)
20 7.5 to 26 100%
50%
1
2
40 14 to 50 100%
50%
2
3
> 60 30 to 90 100% 3
ÎIn case of a zero shift (e.g. due to a sub-
sequent change in the restriction setting
or supply pressure), check the zero set-
ting and readjust it.
ÎThe adjustment range of the Xp restric-
tion is restricted by the pointer and stop
to one turn (Fig.12). Do not remove the
pointer!
Zul. Supply Alim.
Fig.12: Setting the Xp restriction
If the pointer has been removed
unintentionally, an initial setting can be
performed as follows:
1. Close the restriction by turning it clock-
wise until you feel a slight resistance.
2. Based on this position, open the restric-
tion one quarter turn.
3. Press on the plastic ring with the pointer
at the 0° position.
4. Set the restriction in the range between
90° and 180°.
5. Set Xp as described in section7.3.1.

18 EB 8359-1 EN
Operation
7.3.2 Setting for actuator with
fail-safe action “stem ex-
tends”
To ensure that the total closing force of the
actuator acts on the valve, proceed as fol-
lows:
ÎWith direct operating direction <<: ad-
just starting point to 0.23bar (slightly
raised).
ÎWith reverse operating direction <>: ad-
just starting point to 0.97bar (slightly
lowered).
Starting point (zero) e.g. 0.23bar
1. Turn the zero adjustment screw (4) until
the plug stem just starts to move out of its
resting position (observe travel indica-
tor).
2. Reduce the input signal to 0bar and
slowly increase it again. Check whether
the plug stem starts to move at exactly
0.23bar and correct, if necessary.
Upper range value (span) e.g. 1bar
3. Once the starting point has been set, in-
crease the input signal. At exactly 1bar,
the plug stem must stand still, having
moved through 100% travel (watch the
travel indicator at the valve).
If the upper range value is incorrect,
move the pin (2) as follows to correct it:
4. Move towards
Lever end àTo increase the
travel
Fulcrum àTo reduce the
travel
After correcting the input signal, re-ad-
just zero. Then check the upper range
value again.
Repeat the correction procedure until both
values are correct.
If a pressure gauge is available, check
whether the actuator is completely vented at
an input signal of exactly 0.2bar (operating
direction <<) or exactly 1.0bar (operating
direction <>).
7.3.3 Setting for actuator with
fail-safe action “stem re-
tracts”
When using an actuator with "actuator stem
retracts" fail-safe action, the diaphragm
chamber must be pressurized with a signal
pressure that is high enough to tightly close
the valve against the upstream pressure in
the plant.
ÎOperating direction <<: Upper range
value of reference variable 1bar
ÎOperating direction <>: Lower range val-
ue of reference variable 0.2bar
The required signal pressure is either indicat-
ed on the positioner label or the required
supply pressure can be roughly calculated as
described in section6.2.
Starting point (zero) e.g. 1bar
1. Adjust the input signal to 1bar at the
pressure adjuster.
Turn the zero adjustment screw (4) until
the valve just starts to move from its ini-
tial position.

EB 8359-1 EN 19
Operation
2. Increase the input signal and slowly re-
duce it again to 1bar. Check whether
the valve starts to move at exactly
0.1bar.
Correct any deviation at the zero adjust-
ment screw (4).
ÎTurn it counterclockwise to move the
valve earlier from its nal position
ÎTurn it clockwise to move the valve later
from its nal position
Upper range value (span) e.g. 0.2bar
3. Once the starting point has been set, in-
crease the input signal to 0.2bar at the
pressure adjuster.
At exactly 0.2bar, the plug stem must
stand still, having moved through 100%
travel (watch the travel indicator at the
valve).
4. If the upper range value is incorrect,
move the pin (2) to correct it. Readjust
1bar and turn the zero adjustment screw
(4) until the pressure gauge indicates the
required signal pressure (see also 6.2).
If no pressure gauge has been installed,
set the starting point to 0.97bar instead.
7.4 Exchanging the range
spring
If the range is to be altered or changed to
split-range operation, replace the range
spring as shown in Fig.1 as follows:
1. Unscrew screw (7) on the range spring.
Undo hexagon socket screw (5) and pull
out the lever together with shaft.
2. Exchange range spring. Slide lever with
shaft through sleeve (3), positioner hous-
ing and bracket (6.1).
3. Secure range spring with the screw (7).
4. Move bracket and shaft until the screw
(5) sits on the attened part of the shaft.
Tighten screw (5). Allow for a play of
0.05 to 0.15mm between the lever (1)
and the sleeve (3) as well as between the
range spring (6) and the positioner hous-
ing.

20 EB 8359-1 EN
Upgrading the pneumatic positioner
8 Upgrading the pneumatic
positioner
The pneumatic positioner can be converted
into a Type4763 Electropneumatic Position-
er with a conversion kit.
Note:
The version suitable for oxygen of the
Type4765 Pneumatic Positioner can-
not be converted to form a
Type4763 Electropneumatic Position-
er.
Besides the required Type 6109 or
Type6112 i/p module (see Fig.13), the as-
sociated conversion kit (including printed cir-
cuit boards, cable gland and mounting
screws) must be ordered.
Note:
For details on the converted
Type4763 Positioner, refer to Mount-
ing and Operating Instructions
uEB8359-2EN.
With Type 6109:
1. Undo the connecting plate (6) and re-
move along with sealing element (7). Pull
off the hose (5).
2. Unscrew the connecting nipple (4) from
the housing.
3. Push the i/p module over the plug con-
nection onto the printed circuit board.
4. Insert the sealing element (7), on the bot-
tom, into the opening of the printed cir-
cuit board so that the restriction with l-
ter (8) are situated on the right side
above the innermost of the two housing
holes (supply air) when the module
(dashed line in Fig.13) is installed.
5. Secure the module and the printed circuit
board in the housing (two screws for the
module, one screw for the printed circuit
board). Subsequently assemble the cable
gland (1) along with the seal.
With Type 6112:
1. Proceed as described in steps 1 and 2 of
Type6109
2. Place the i/p module on the plug of the
printed circuit board, and tighten the
side terminal screws.
3. Check whether the seals (10, 11) are
properly inserted on the bottom side.
When the module (dashed line in
Fig.13) is installed, the seal with restric-
tion and lter must be situated on the
right side above the innermost of the two
housing holes (supply air).
4. Secure the module and the printed circuit
board in the housing (two screws for the
module, one screw for the printed circuit
board). Subsequently assemble the cable
gland (1) along with the seal.
Legend for Fig.13
1 Cable gland
2 Printed circuit board
3 i/p converter module
4 Connecting nipple
5 Hose
6 Connecting plate
7 Sealing element
8 Restriction
10 Seal
11 Seal with restriction

