Electropneumatic Positioner and

Pneumatic Positioner
Type 3760

Application
Single-acting positioners for direct attachment to pneumatic
control valves. Supplied with an electric input signal of 4 to
20 mA or a pneumatic input signal of 0.2 to 1 bar (3 to 15 psi).
For travels from 5 to 15 mm JIS

The positioners ensure a predetermined assignment of the valve

stem position (controlled variable x) to the control signal (refer-
ence variable w). They compare the control signal issued by a
controller with the travel of the control valve and issue an output
signal pressure pst (output variable y).
The positioners have the following special features: suitable for
normal and split-range operation; reversible operating direc-
tion; excellent dynamic response; low supply air consumption,
insensitive to mechanical vibration; compact, low-maintenance
design; optionally available with inductive limit switch and, on
request, output pressure limiter.
A version for hazardous areas with type of protection "Intrinsic
safety" II 2 G EEx ia IIC T6 according to ATEX is available for
the proximity switch circuit and for the signal circuit of the
electropneumatic positioner (see summary of explosion protec-
tion certificates).
Type of protection EEx d with Type 6116 i/p Converter (Fig. 2) Fig. 1 · Type 3760 Positioner
Direct attachment to Type 3277 Pneumatic Actuators with effec-
tive areas of 120, 240 and 350 cm² (see T 8310-1 EN).
Optionally available with a pressure gauge (scale 0 to 6 bar
and 0 to 90 psi) to monitor the signal pressure. The pressure
gauge housing is made of stainless steel; connection optionally
nickel-plated or completely of stainless steel.

Versions
Type 3760 Electropneumatic Positioner (Fig. 1)
Version suitable for non-hazardous areas. Signal pressure
ranges from 0 to 6 bar (0 to 90 psi); supply air from 1.4 to 6 bar
(20 to 90 psi). Reference variable: standard version 4 to
20 mA.
Type 3760 Electropneumatic Positioner · Same version as
above, except for its use in hazardous areas. Type of protection
II 2 G EEx ia IIC T6 for the signal circuit
Type of protection EEx d with Type 6116 i/p Converter (Fig. 2)
On request, also available with an intrinsically safe inductive
limit switch.
Type 3760 Pneumatic Positioner
Reference variable 0.2 to 1 bar (3 to 15 psi), signal pressure
ranges from 0.2 to approx. 6 bar (3 to approx. 90 psi); supply
air from 1.4 to 6 bar (20 to 90 psi). Fig. 2 · Micro-flow valve with EEx d positioner
On request, also available with an intrinsically safe inductive (Type 3760 with Type 6116 i/p Converter)
limit switch.

Associated Information Sheet T 8350 EN Edition February 2010

Data Sheet T 8385 EN

Principle of operation
The only difference between the positioners is that the elec-
tropneumatic positioner is equipped with an i/p converter (2).
Both positioners ensure a predetermined assignment of the
valve stem position to the control signal. The controlled variable
Travel
x is the valve travel. The reference variable w is either a DC sig-
nal (i) for the electropneumatic positioner (i/p) or a pneumatic 1 2 34 5 6 7
signal (pe) for the pneumatic positioner (p/p). The DC signal Supply air
and the pneumatic signal are both issued by a connected con-
troller. The manipulated variable y is the positioner's output p
e

pressure (pst).
14
The Type 3760 Positioners are designed for direct attachment to
SAMSON Type 3277 Actuators.
In the electropneumatic positioner, the direct current signal i is
transmitted from the controller to the i/p converter (2), where it p
st
is converted into a proportional air pressure pe of 0.2 to 1 bar 13 12 11 10 9 8
Force switch,
or 3 to 15 psi. In the pneumatic positioner, the control signal pe
Direct action >>
provided as air pressure is directly transmitted to the measuring
diaphragm (3).
p
e
The pneumatic control signal pe produces a force at the measur- p
st
ing diaphragm (3) which is compared to the force of the range Force switch,
spring (7). The motion of the measuring diaphragm (3) is trans- Reverse action <>
mitted to the double plug (13) of the force switch (12) via the le- 14
ver (4). As a result, a corresponding signal pressure pst is pro-
duced. Any changes in the control signal pe or the valve stem
position causes changes in the signal pressure pst. Thus, the plug
stem of the valve moves to the position which corresponds to the Legend
reference variable. 1 Pressure regulator 8 Adjustment screw (span)
The positioners can be used for both standard and split-range 2 i/p converter 9 Clamping screw
operation. Note that the signal pressure range (range of the 3 Measuring diaphragm 10 Clamp
output pressure pst) must match the spring range of the actuator. 4 Diaphragm lever 11 Axis of rotation
In split-range operation, the output signal of a control station in- 5 Adjustment screw 12 Force switch
tended to control two control valves is divided in such a way that (zero) 13 Double plug
each actuator passes through its full travel at half the input span. 6 Lever 14 Screw
For a span between 0.2 and 1 bar, for example, the first valve is 7 Range spring
adjusted to the first half (from 0.2 to 0.6 bar), the second is ad-
justed to the second half (from to 0.6 to 1 bar).
The adjustment screws for zero (5) and span (8) are used to set Fig. 3 · Functional diagram of Type 3760 Positioner
the lower and upper range values of the input signal. The range
spring (7) must be chosen to match both the rated travel of the
control valve and the nominal span of the reference variable.

Operating direction
When the pneumatic control signal pe (reference variable) in-
creases, the signal pressure pst can be selected to be increasing
(direct action >>) or decreasing (reverse action <>). The operat-
ing direction is determined by the position of the force switch
(12) and can also be changed on site.

2 T 8385 EN
Table 1 · Technical data
Travel range 5 to 15 mm (see Table 2 for range springs)
Reference variable Pneumatic 0.2 to 1 bar (3 to 15 psi)
Span for split-
Electric 4 to 20 mA (Ex only) · Ri 250 7%
range operation
0 to 50 % or 4 to 20 mA (non-Ex) · Ri 200 7%
50 to 100 % 0 to 20 mA · Ri 200 7%
(Ri = internal resistance at 20 °C) 1 to 5 mA · Ri 880 7%
Supply air 1.4 to 6 bar (20 to 90 psi)
Max. particle size and density: Class 2 · Oil content: Class 3 · Pressure dew point:
Class 3 or at least 10 K below the lowest ambient temperature to be expected
Signal pressure pst (output) Max. 0 to 6 bar (0 to 90 psi)
Characteristic Linear, deviation from terminal-based conformity 1.5 %
Hysteresis 0.5 %
Sensitivity < 0.1 %
Operating direction Reversible
Air consumption in steady state At 0.6 bar signal pressure and supply pressure up to 6 bar 100 In/h
Air output capacity At p = 1.4 bar 1600 In/h · At p = 6 bar 5000 In/h
Transit times with Type 3277 Actuator
120 cm²: 2 s · 240 cm²: 6 s · 350 cm²: 8 s
(15 mm travel, 0.2 to 1 bar signal pressure)
Permissible ambient temperature –20 to +70 °C
(Note the limits in the EC Type Down to –30 °C with metal cable gland
Examination Certificate) Down to –40 °C with metal cable gland and Type 6112 i/p Converter
The limits in the EC Type Examination Certificate additionally apply for explosion-
protected versions
–40 to 70 °C with Type 3760 used as pneumatic positioner without proximity switches
Influences Temperature (zero) 0.03 %/°C
Span 0.03 %/°C
Vibrations Between 5 to 120 Hz and 2 g 0.5 %
Supply air 1 % between 1.4 and 6 bar
Variable position when turned 180° < 3.5 %
Degree of protection IP 54 (IP 65 special version)
Materials Housing: Polyamide · External parts: Stainless steel 1.4571 and 1.4104
Measuring diaphragm: Fluorosilicone rubber · Cable gland: Polyamide, M20 x 1.5
Weight 0.6 kg
Additional equipment
Inductive limit switch Type SJ2 - SN
Control current circuit Values corresponding to the downstream transistor relay
Hysteresis at rated travel 1%

.
Table 2 Range springs
Range
Reference variable (%) Travel (mm)
spring

0 to 100 12/15
1
Split-range 0 to 50 or 50 to 100 6/7.5

2 0 to 100 6/7.5

3 Split-range 0 to 50 12/15

4 Split-range 50 to 100 12/15

5 0 to 100 5

6 0 to 100 20

7 Split-range 0 to 50 or 50 to 100 5

3 T 8385 EN
Positioner attachment
The positioners are designed for direct attachment to Type 3277
Actuators with effective areas 350 cm² and smaller. They are Actuator stem extends
secured directly to the actuator yoke using two screws.
No external piping is necessary for actuators with effective are-
as of 120 cm². The signal pressure pst from the positioner is
transmitted to the desired diaphragm chamber via a switchover
plate and internal air ducts.

Combination of positioner and actuator

Fig. 4 illustrates the different types of attachment. The specifica- Direct >> Reverse <>
Left attachment Right attachment
tions "left attachment" or "right attachment" apply when look-
ing onto the switchover plate and the signal pressure connec-
tion. Depending on the intended attachment, the positioner is to Actuator stem retracts
be secured on either the right or the left side of the yoke.
Subsequent conversion, such as reversing the operating direc-
tion of the positioner control loop or modifying the actuator's
fail-safe action, is possible. In this case, note that the positioner
must also be attached in a different position.
Reverse <> Direct >>
Fail-safe action Left attachment Right attachment
The Type 3277 Pneumatic Actuator has the two fail-safe actions
which move the valve stem to the predetermined position when-
ever the signal pressure decreases or the air supply fails.
Actuator stem extends:
Whenever the pressure acting on the surface of the diaphragm Fig. 4 · Attachment position
decreases or the air supply fails, the force of the compression
springs in the actuator causes the actuator stem to extend.
Actuator stem retracts:
Whenever the pressure acting on the surface of the diaphragm
decreases or the air supply fails, the force of the compression
springs in the actuator causes the actuator stem to retract.
Further details can be found in Data Sheet T 8310-1 EN.

Summary of explosion protection certificates for Type 3760

Type of approval Certificate number Date Comments

EC Type Examination Certificate PTB 02 ATEX 2076 2002-07-18 II 2 G EEx ia IIC T6;
Inductive limit switches PTB 99 ATEX 2219 X; Type 3760-1

Statement of Conformity PTB 03 ATEX 2181 X 2003-09-30 II 3 G EEx nA II T6; Zone 2; Type 3760-8

CSA approval LR 54227-23 1996-04-22 Class 1, Div. 1; Groups A, B, C, D

NLRC approval also valid in USA
Addendum 2005-09-16 Class I, Groups A, B, C, D
LR 54227-32 1999-10-14 Encl. 3; Inductive limit switches; Type 3760-3

FM approval 3020228 2005-02-28 Classes I, II, III; Div 1; Groups A, B, C, D, E, F, G

Revision Class I, Zone 0 AEx ia IIC T6;
Class I; Div. 2; Groups A, B, C, D
Class II; Div. 2; Groups F, G; Cl. III
NEMA 3R
With inductive limit switch; Type 6109 and Type 6112 i/p Module;
Type 3760-3

Refer to Data Sheet T 6116 EN for EEx d certificates for Type 6116 i/p Converter.

4 T 8385 EN
 Electrical connections Dimensions in mm

Pneumatic version
Limit switch

+ _
Switching amplifier
110 29
acc. to EN 60947-5-6

"A" M20 x 1.5

Ø40
Output Supply air

Electropneumatic version Pressure

With mA signal Limit switch
gauge for
Output
36 output
+11 _12 + _
Switching amplifier 35
acc. to EN 60947-5-6

Control signal i

38
Output Supply air

Connection with cable socket Connector

(DIN 43650) acc. to
DIN 43650
4

1
2
128
3

Cable socket Terminal

1 + 11 i/p converter
2 - 12
3 + Limit switch View as seen from “A”
4 -
27 input signal
121 (3760–...00)
36

84

17
9 supply
48

1 1
Pneumatic connections G 8 or 8 NPT

5 T 8385 EN
Article code

Positioner Type 3760- x x x x x x 0 0 0 0 0 0

Explosion protection
Without 0 2/3
II 2 G EEx ia IIC T6 acc. to ATEX 1 0
FM/CSA intrinsically safe/non incendive 3 0
II 3 G EEx nA II T6 acc. to ATEX 8 0
Limit switches
Without 0
1 x inductive, SJ2 SN 1
Pneumatic connection
1
ISO 228/1 - G 8 1
1
8 - 27 NPT 2
Electrical connection
Without 0 0 0
Cable gland M20 x 1.5, blue (plastic) 1
Cable gland M20 x 1.5, black (plastic) 2
Connector DIN 43650-AF3-PG11 3
i/p module
Without 0 0
Type 6109 1 1
Type 6112 2 1/2/3
Reference variable
0.2 ... 1.0 bar / 3 ... 15 psi 0
4 ... 20 mA 1
0 ... 20 mA 2
1 ... 5 mA 3

Accessories
Adapter ½ NPT for electrical connections

Additional specifications
Range spring 1/ ... 7/
Pressure gauge Without/with
Gauge housing CrNiMo steel,
Connection optionally nickel-plated/completely CrNiMo steel

Specifications subject to change without notice.

SAMSON AG · MESS- UND REGELTECHNIK

Weismüllerstraße 3 · 60314 Frankfurt am Main · Germany
2010-02

Phone: +49 69 4009-0 · Fax: +49 69 4009-1507

Internet: http://www.samson.de T 8385 EN