Samson 3768 Service manual

Mounting and
Operating Instructions
EB 8356 EN
Edition February 2013
Type3768 Inductive Limit Switch

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 8356 EN
Note on these mounting and operating instructions
These mounting and operating instructions (EB) assist you in mounting and operating the de-
vice 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 additional questions not related to the contents of these instructions, con-
tact SAMSON's After-sales Service department (aftersalesser[email protected]).
The mounting and operating instructions for all supplied devices are
included in the delivery. The latest versions of the documents are available
on our website at www.samson.de > Product documentation. You can
enter the document number or type number in the [Find:] eld to look for
a document.
Referenced documentation
The documents for the devices used in combination with the limit switch apply in addition to
these mounting and operating instructions.

Contents
EB 8356 EN 3
1 General safety instructions.............................................................................5
2 Design and principle of operation ..................................................................6
2.1 Technical data ...............................................................................................7
2.2 Versions and article code................................................................................8
2.3 Summary of explosion protection approvals.....................................................9
3 Attachment to the valve ...............................................................................10
3.1 Direct attachment.........................................................................................10
3.1.1 Attachment of version with solenoid valve ......................................................10
3.2 Attachment according to IEC60534-6...........................................................12
3.2.1 Mounting sequence......................................................................................12
3.2.2 Initial adjustment of travel.............................................................................14
3.3 Attachment to rotary actuators ......................................................................14
3.3.1 Mounting the lever with feeler roll..................................................................14
3.3.2 Mounting the intermediate piece ...................................................................14
3.3.3 Aligning the cam disk...................................................................................16
3.3.4 Reversing amplier for double-acting actuators ..............................................18
4 Electrical connections...................................................................................24
4.1 Pneumatic connections for version with solenoid valve.....................................27
5 Operation – Adjusting the limit contacts .......................................................28
6 Servicing explosion-protected devices ..........................................................30
7 Maintenance and calibration .......................................................................30
8 Dimensions in mm.......................................................................................31

EB 8356 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 device:
−The device 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.
−Explosion-protected versions of this device are to be operated only by personnel who has
undergone special training or instructions or who is authorized to work on explosion-pro-
tected devices in hazardous areas. See section6.
−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 in-
admissible 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 sta-
tion.
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 Directive 2014/34/EU and
the Directive 2014/30/EU. The declaration of conformity is included at the end of
these instructions.


6 EB 8356 EN
Design and principle of operation
2 Design and principle of oper-
ation
The Type3768 Limit Switch is designed for
attachment to pneumatic control valves. It is
tted with inductive contact limits that issue a
limit signal whenever the valve travel ex-
ceeds or falls below a certain preset limit, es-
pecially when the valve has reached one of
its end positions. The limit signal is transmit-
ted to alarm or indicating equipment.
The limit switch can also available be tted
with a solenoid valve to move the valve to its
fail-safe position.
The limit switch is designed either for direct
attachment to SAMSON Type3277 Actua-
tors or for attachment to actuators according
to IEC60534-6 (NAMUR) using an adapter
housing.
The valve travel is transmitted by the pin
(1.1) to the lever (1) and converted into a ro-
tary motion. The shaft (2) transfers this rota-
ry motion to two adjustable metal tags (4)
which operate the associated proximity
switches (5).
The operation of the inductive limit switches
requires switching ampliers to be connected
in the output circuit (see section4).
Version with solenoid valve
When tted with a solenoid valve, the con-
trol valve can be moved to the fail-safe posi-
tion, regardless of the control signal issued
by the control equipment. If a control signal
corresponding to the binary signal '0' (OFF)
is applied to the input, the signal pressure pst
is shut off and the actuator is vented. The ac-
tuator springs move the valve to its fail-safe
position.
When a control signal corresponding to the
binary signal '1' (ON) is applied to the in-
put, the signal pressure pst is applied to the
actuator, allowing the valve to move accord-
ing to the input signal issued by the control
equipment.
46
5
3211.1
7
supply
u[V]
pst
1Lever
1.1 Coupling pin
2 Shaft
3 Spring
4Metal tag
5Proximity switch
6Adjustment screw
7 Pressure regulator
Fig. 1: Functional diagram

EB 8356 EN 7
Design and principle of operation
2.1 Technical data
Travel range Direct attachment to Type3277 Actuator: 7.5 to 30mm
Attachment according to IEC60534 (NAMUR):
7.5 to 120mm
Inductive proximity switches 2x SJ2-SN
Control circuit Specications corresponding to connected switching
amplier
Hysteresis at rated travel ≤1%
Permissible ambient temperature –20 to +80°C with plastic cable gland
–40 to +80°C with metal cable gland
Special version down to –45°C
The limits in the type examination certicate additionally
apply to explosion-protected versions.
Solenoid valve
Supply air Supply air: 1.4 to 6bar (20 to 90psi)
Input Binary DC voltage signal
Nominal signal 6V DC 12VDC 24VDC
Signal '0' (no response) 1) ≤ 1.2V ≤ 2.4V ≤ 4.7V
Signal '1' (response) 2) ≥ 5.4V ≥ 9.6V ≥ 18.0V
Coil resistance Ri at 20°C 2909Ω 5832Ω 11714Ω
KV coefcient 0.14m³/h
Air consumption 'OFF' ≤60ln/h · 'ON' ≤10ln/h
Closing time with Type3277 Actuator 240cm² 350cm² 700cm²
For rated travel with
bench range
0.2 to 1bar ≤1s ≤1.5s ≤4s
0.4 to 2bar ≤2s ≤2.5s ≤8s
0.6 to 3bar ≤1s ≤1.5s ≤5s
Degree protection
without/with solenoid
valve
Without IP65
With IP65 (IP65 and NEMA 4X, lter check valve,
see Table4 on page22)
Compliance ·
Materials
Housing Die-cast aluminum, chromated and plastic coated
External parts Stainless steel 1.4571 and 1.4104
1) DC voltage signal at –20°C
2) DC voltage signal at +80°C

8 EB 8356 EN
Design and principle of operation
2.2 Versions and article code
Limit switch Type3768- x 2x0 0 xxxx0x x 0
Explosion protection
Without 0 2/7
II 2G Ex ia IIC T6 acc. to ATEX 1
CSA/FM intrinsically safe/non incendive 3
II 3G Ex nA II T6 acc. to ATEX 82/7
Solenoid valve
Without 0
6V DC 2
12V DC 3
24VDC 4
Pneumatic connections
Without 0 0
¼-18NPT 1
ISO221/1-G¼ 2
Electrical connection
Plastic cable gland M20x1.5, blue 1 0
Plastic cable gland M20x1.5, black 2 0
Cable gland M20x1.5, nickel-plated brass 7 2
Body version
Aluminum 0
CrNiMo steel 2
Temperature range
Standard 0
–45 to 80°C 2
Special versions
On request x x x x

EB 8356 EN 9
Design and principle of operation
2.3 Summary of explosion protection approvals
Type Certication Type of protection
3768-1
Number GYJ15.1218X
Ex ia IIC T4...T6 GbDate 2015-06-16
Valid until 2020-06-15
No. PTB 02 ATEX 2077
II 2G Ex ia IIC T6
Date 2002-07-19
EC type examination
certicate
3768-3
Number 1607265 Ex ia IIC T6; Class I Zone 0;
Class I, II, Div. 1, Groups A, B, C, D, E, F,
G;
Class I, II, Div. 2, Groups A, B, C, D, E, F,
G;
Date 2005-06-19
No. 3020228 Class I, Zone 0 AEx ia IIC
Class I, II, III, Div. 1, Groups A, B, C, D, E,
F, G
Class I, Div. 2, Groups A, B, C, D;
Class II, Div. 2 Groups F, G; Class III
Date 2005-02-28
3768-8
Number GYJ15.1219X
Ex ic IIC T4...T6 Gc
Ex nA IIC T4...T6 Gc
Date 2015-06-16
Valid until 2020-06-15
Number PTB 03 ATEX 2182 X
II 3G Ex nA II T6
Date 2003-09-30
Statement of
conformity
3768-9
Number RU C-DE08.B.00199 1Ex ia IIC T6/T5/T4 Gb X
Ex tb IIIC T80°C Db X
2Ex nA IIC T6/T5/T4 Gc X
2Exic IIC T6/T5/T4 Gc X
Ex tc IIIC T80°C Dc X
Date 2014-02-14
Valid until 2019-02-13

10 EB 8356 EN
Attachment to the valve
3 Attachment to the valve
The limit switch can be mounted either di-
rectly to SAMSON Type3277 Actuator or to
valves with cast yokes or rod-type yokes ac-
cording to IEC60534-6 (NAMUR).
Combined with an intermediate piece, the
limit switch can also be mounted on rotary
actuators.
The standard limit switch is delivered without
accessories. Any additionally required ac-
cessories are listed together with their order
numbers in the tables on page20 on-
wards.
The limit switch may be mounted on the
right-hand or left-hand side of the valve.
Any subsequent changes to the mounting
position cause the switching function of the
limit switch to change as well. See section5.
3.1 Direct attachment
1. Fasten the clamp (1.2) to the actuator
stem, making sure that the fastening
screw rests in the groove of the actuator
stem.
2. Fasten the associated lever D1 or D2 to
the lever of the limit switch.
3. Secure the intermediate plate (15) with
the gasket facing towards the yoke.
4. Position and fasten the limit switch onto
the intermediate plate, making sure that
the lever D1 or D2 slides in line over the
pin(1.1) of the clamp (1.2).
5. Mount cover (18).
6. Mount the vent plug suitable for the cor-
responding degree of protection on the
cover (18).
3.1.1 Attachment of version
with solenoid valve
To establish the signal pressure connection to
the actuator, use a connection block or swi-
tchover plate listed in the tables in
page20 onwards. An M3 screw plug is
located on the back of this device version.
Actuators with 240 to 700cm² effective
areas
1. Make sure that the tip of the gasket(16)
projecting from the side of the connec-
tion block (Fig. 2, middle) is positioned
to match the actuator symbol for the ac-
tuator's fail-safe action "actuator stem
extends" or "actuator stem retracts".
If this is not the case, unscrew the three
fastening screws and lift off the cover.
Turn the gasket (16) by 180° and re-in-
sert it.
The old connection block version requires
the switch plate (13) to be turned to align
the actuator symbol with the arrow mark-
ing.
2. Place the connection block with the asso-
ciated gaskets against the limit switch
and the yoke. Fasten it using the screw.
For actuators with fail-safe action "actua-
tor stem retracts", additionally mount the
external signal pressure pipe.
SUPPLY
1.2
18
D2
D1
15
15
Type3277
Connection block
only for version with
solenoid valve
Switchover plate
only for version with solenoid valve
Type3277-5 with 120cm²
View onto the signal pressure connection
< Left attachment Right attachment >
Actuator stem
< extends retracts >
Signal pressure connection
< internal over pipe connection >
With switch plate (old)
Switch plate (13)
Marking
Marking
Actuator stem
retracts
Symbol for
actuator stem
retracts
Symbol for
actuator stem
retracts
Signal pressure
input for left
attachment
Signal pressure
input for right
attachment
Tip of gasket
(16)
extends
extends
Clamp
extends
Cover
Side view of
connection block
with gaskets (new)
Fig. 2: Direct attachment · Mounting of the clamp and signal pressure connection for version with
solenoid valve