Pneumatic or Electropneumatic Positioner for Rotary Actuators Type 3761 Fig. 1 Type 3761 Positioner Mounting and Operating Instructions EB 8386 EN Edition June 2004
Contents Contents Page 1 Design and principle of operation...................... 4 1.1 Technical data................................ 6 2 Attachment to rotary actuators....................... 7 2.1 Adjusting the operating direction....................... 9 2.2 Selecting and aligning the cam disc...................... 10 3 Connections................................. 13 3.1 Pneumatic connections............................ 13 3.1.1 Pressure gauges............................... 13 3.2 Electrical connections............................ 14 4 Operation Adjustment........................... 16 4.1 Starting point and reference variable..................... 16 4.2 Adjustment................................. 17 4.2.1 Actuator version: Valve closed without supply air............... 17 4.2.2 Actuator version: Valve open without supply air................ 18 4.2.3 Double-acting actuator: Valve opens counterclockwise and valve opens clockwise............................ 18 5 Adjusting the limit switch.......................... 20 6 Servicing explosion-protected devices.................... 21 7 Dimensions in mm.............................. 22 Test certificate................................ 23 Note: Devices with a CE marking fulfill the requirements of the Directive 94/9/EC as well as the Directive 89/336/EEC. The Declaration of Conformity can be viewed and downloaded from the Internet under http://www.samson.de. 2 EB 8386 EN
Safety instructions Versions Assembly, start-up and operation of the device may only be performed by trained and experienced personnel familiar with this product. According to these mounting and operating instructions, trained personnel is referred to persons who are able to judge the work they are assigned to and recognize possible dangers due to their specialized training, their knowledge and experience as well as their knowledge of the relevant standards. Explosion-protected versions of this device may only be operated by personnel who have undergone special training or instructions or who are authorized to work on explosion-protected devices in hazardous areas. Any hazard which could be caused by the process medium, the signal pressure and moving parts of the control valve are to be prevented by means of appropriate measures. If inadmissible motions or forces are produced in the pneumatic actuator as a result of the level of the supply air pressure, this must be restricted by means of a suitable pressure reducing station. Proper shipping and appropriate storage of the device are assumed. Positioner versions Type 3761- X X X X X X Explosion protection Without EEx ia IIC T6 0 1 Design Pneumatic Electropneumatic Tight-closing function Without At a reference variable of 0 % At a reference variable of 100 % Type of function Single output Double output Accessories Without electric limit switch With electric limit switch Pneumat. connections ISO-228/1 G 1/4 1/4-18 NPT 0 0 1 2 0 0 1 2 1 2 0 1 1 2 EB 8386 EN 3
Design and principle of operation 1 Design and principle of operation The pneumatic or electropneumatic positioner ensures the assignment of the valve position (controlled variable) to the control signal (reference variable). The input signal received from a control unit is compared to the control valve s angle of rotation, and a corresponding pneumatic signal pressure (output variable) is produced. The positioner mainly consists of a pneumatic unit including a tension spring (4), diaphragm lever (5) and the amplifier (8) with double plug (7). The electropneumatic positioner is additionally equipped with an electropneumatic converter (10). Any change of the valve position (controlled variable) is carried over as a rotary motion via cam disc (2) and from there via pick-up lever (1) as well as the tension spring (4) to the pneumatic system. The control signal (input signal of positioner) from the control unit is, if it is a pneumatic signal, applied as pressure signal p e directly to the measuring diaphragm (6). Whereas a dc current input signal in the range of, for example, 4 to 20 ma, is directly passed on to the electropneumatic converter (i/p converter) where it is converted into a proportional pressure signal p e. The pressure signal p e creates a force on the measuring diaphragm (6), which is balanced by the force of the tension spring (4). The movement of the measuring diaphragm is passed on to the double plug (7) of the amplifier (8) through the lever (5) so that a respective signal pressure p st is produced. The positioner s principle of operation is determined by equipping it either with one (single-acting) or two (double-acting) amplifiers. The operating direction of the signal pressure with increasing << or decreasing <> input signal, can be changed for single-acting positioners by relocating the amplifier. With the double-acting version, you are required to reverse the signal pressure connections. Zero is corrected via an adjustment screw, angle of rotation is given by the cam disc. Tight-closing function: For electropneumatic positioners with tightclosing function, the rotary actuator is completely vented or filled (depending on the operating direction) as soon as the reference variable falls below or exceeds a given value. For Type 3761-x21x, the deactivate function is initiated when the switching point of 4.08 ma is not reached. The actuator is maximum vented. For Type 3761-x22x, the activate function is initiated when 19.92 ma are exceeded. The actuator is filled to its maximum. 4 EB 8386 EN
Design and principle of operation 4 3 Fitting position marked 5 p e 1 I 6 p st2 Output 238 N A 2 Position 2 Output 238 Position 1 Output 138 p st1 Output 138 p i i Input 27 7 8 9 10 Supply 9 Fig. 2 Functional diagram 1 Pick-up lever 7 Double plug 2 Cam disc 8 Amplifier 3 Zero point adjuster 9 Fastening screw 4 Tension spring 10 i/p converter 5 Diaphragm lever (for electropneum. versions) 6 Measuring diaphragm EB 8386 EN 5
Technical data 1.1 Technical data Type 3761 Positioner Angle of rotation 55 /70 /75 /90 Reference variable Electric 4 to 20 ma (min. current 3.6 ma), may only be operated from a current source, Load: 300 Ω at 20 ma (350 Ω at 20 ma with tight-closing function and explosion-protected version) Reverse polarity protection, static destruction limit 60 ma or 6.4 V (without explosion protection) or 7.6 V (explosion-protected version) Pneumatic 0.2 to 1.0 bar (3 to 15 psi) Supply air pressure 1.4 to 6 bar (20 to 90 psi) Signal pressure 0 to 6 bar (0 to 90 psi) Characteristic Linear, deviation from terminal-based conformity 2 % Cam discs 90 linear standard, other see table on page 10 Operating direction Reversible Principle of operation Single-acting or double-acting Hysteresis 1 % Variable position 7 % Tight-closing function (can be deactivated) Type 3761-x21x: Type 3761-x22x: Deactivation when reference variable 4.08 ma Activation when reference variable 19.92 ma Air consumption in steady state Supply air 1.4 bar 6 bar Single-acting Double-acting 80 ln/h 150 ln/h 200 ln/h 350 ln/h Air supply 3000 ln/h at 2 bar 6000 ln/h at 6 bar Permissible ambient temperature 20 to +70 C, with metal cable entry 30 to +70 C For explosion-protected devices: values of certificate apply additionally Degree of protection IP 54 (IP 65 optional) Weight Approx. 0.9 kg Additional electrical equipment (optional) Electric limit switch (microswitch with gold-plated contact, SPDT) 250 V AC, 3 A 6 EB 8386 EN
Attachment to rotary actuators 2 Attachment to rotary actuators Accessories Mounting kit VDI/VDE 3845, additionally a bracket (2) included in the scope of actuator delivery is required Mounting kit for SAMSON Type 3278 incl. bracket Order no. 1400-7595 160 cm 2 1400-7615 320 cm 2 1400-7616 The mounting kit consists of a follower plate, coupling wheel, scale plate and coupling lever as well as a hose clamp and a clamping screw. For SAMSON Type 3278 Rotary Actuators, you must first mount the spacer delivered with the actuator to the free shaft end of the rotary actuator. 1. Screw mounting bracket (2) to the positioner using 4 screws (2.1). 2. Push follower plate (5) on the slotted actuator shaft or the spacer (7). 3. Push coupling wheel (4) with flat side facing the actuator on the follower plate (5). Make sure that you position the oblong hole of the coupling wheel in such a manner that the clamping screw (3.1) of the coupling lever (3) can easily be accessed when the valve is in closing position. 4. Screw coupling wheel and follower plate firmly to the actuator shaft using the slotted pan head screw (6) and disc spring (6.1). 1 6 6.1 5 2 2.1 3.1 3 4 7.1 7 1 Positioner 2 Mounting bracket 2.1 Fastening screw 3 Coupling lever Fig. 3 Attachment to rotary actuator 3.1 Clamping screw 4 Coupling wheel 4.1 Scale plate 5 Follower plate 6 Slotted pan head screw 6.1 Disc spring 7 Actuator shaft/spacer 7.1 Screws EB 8386 EN 7
Attachment to rotary actuators 5. Place coupling lever (3) including hose clamp and clamping screw (3.1) loosely on the coupling wheel (4) so that its contact stud slides into the oblong hole (3.2). 6. Place positioner with mounted bracket (2) carefully on the rotary actuator, ensuring that the positioner axis slides in the coupling lever (3). Note the direction for arranging the connections. 7. Screw the mounting bracket (2) to the rotary actuator using 4 screws (7.1). 8. Attach the adhesive scale plate (4.1) to the coupling wheel so that the arrow tip points to the closing position and can be easily identified when the valve is installed (see Fig. 4). 9. Before you fasten the coupling lever (3) with the clamping screw (3.1), you are required to adjust the cam disc (see section 2.2, page 10). After that, the lever can be clamped on the positioner axis. Control valve opens counterclockwise Control valve opens clockwise 4 3.1 3.2 3 4.1 4 3 Coupling lever 3.1 Clamping screw 3.2 Oblong hole 4 Coupling wheel 4.1 Adhesive scale plate Fig. 4 Aligning the scale plate 4 4 3.1 3.2 3 4.1 8 EB 8386 EN
Attachment to rotary actuators 2.1 Adjusting the operating direction Important! The positioner version with either single- or double-acting output is pre-determined and cannot be changed by adding or removing an amplifier. Single-acting positioner: The operating direction of the positioner is determined by the mounting position of the amplifier. When the input signal (reference variable) increases, the signal pressure p st may either increase (direct operating direction) or decrease (reverse operating direction). The same applies when the input signal decreases. For "direct operating direction", the signal pressure decreases, whereas for "reverse operating direction", it increases. For "direct operating direction", the amplifier must be screwed in mounting position 1 (Fig. 2) and for "reverse operating direction" in mounting position 2. The cover plate must be screwed on the unoccupied position so that the associated supply air bore is sealed. Double-acting positioner: The operating direction is determined by the assignment of the signal pressure outputs 138 and 238 to the two connections (y1 and y2) of the rotary actuator. Note! The designation of the signal pressure connections on the rotary actuator varies depending on the manufacturer. In Figs. 5 and 6, y1 and y2 have been assigned the following function: Single-acting actuator Increasing signal pressure at y1 opens the valve if the closure member rotates counterclockwise. Double-acting actuator Increasing signal pressure at y1 and decreasing pressure at y2 opens the valve if the closure member rotates counterclockwise, or increasing signal pressure at y2 and decreasing pressure at y1 opens the valve if the closure member rotates clockwise. Important! When you relocate the amplifiers, make absolutely sure that both O-rings remain in the base of the housing. EB 8386 EN 9
Attachment to rotary actuators 2.2 Selecting and aligning the cam disc The positioner is supplied with a cam disc version "90 linear ". In case you require a different control characteristic, you have to replace the existing cam disc with a cam disc as listed in the table below. The default setting of the cam disc depends on the control valve version (butterfly valve, ball valve, etc.) and the rotary actuator version used. For the proper assignment, refer to Figs. 5 and 6 below. Fig. 5 shows how to adjust the cam disc for control valves with rotary actuators that are equipped with a spring-return mechanism. The fail-safe action of the control valve "Closed without supply air" or "Open without supply air", is determined by the way the actuator is attached to the valve. For instance, the SAMSON Type 3278 Actuator can be equipped with a butterfly valve with the shaft attached to either the left or the right actuator flange. Fig. 6 shows how to adjust the cam disc when a double-acting springless rotary actuator is used. The direction of rotation, either counterclockwise or clockwise (view from the positioner onto the actuator shaft), depends on how the rotary actuator is mounted to the control valve and how the two signal pressure outputs 138 and 238 are assigned to the connections (y1 or y2) of the rotary actuator. Depending on the rotary actuator s direction of rotation, counterclockwise or clockwise, the starting point of the cam section that must be passed through is on the front side A or the back side B of the cam disc. Table: Cam discs Order no. Linear cam disc 90 0050-0093 Equal percentage cam disc 90 0050-0095 Linear cam disc 70 for butterfly valves 0050-0108 Equal percentage cam disc 70 for butterfly valves 0050-0110 Linear cam disc 75 for Vetec rotary plug valves 0050-0102 Equal percentage cam disc 75 for Vetec rotary plug valves 0050-0104 Linear cam disc 90 for Type 3310 Segmented Ball Valve 0050-0114 Equal percentage cam disc 90 for Type 3310 Segmented Ball Valve 0050-0116 Linear cam disc 70 for Type 3310 Segmented Ball Valve with reverse flow 0050-0126 Equal percentage cam disc 70 for Type 3310 Segmented Ball Valve with reverse flow 0050-0128 Linear cam disc 55 for Type 3310 Segmented Ball Valve, reduced opening angle 0050-0118 Equal percentage cam disc 55 for Type 3310 Segmented Ball Valve, reduced opening angle 0050-0120 10 EB 8386 EN
I I Attachment to rotary actuators Single-acting rotary actuator with spring-return mechanism Control valve opens counterclockwise, cam disc linear (standard) Fail-safe position: Valve closed without supply pressure Orientation of cam disc when control valve closed Direct operating direction Connection: Output 138 Reverse operating direction Connection: Output 238 Refer. variable Sig. press. Valve Cam Refer. variable Sig. press. Valve Cam Increases Increases Opens A Decreases Increases Opens B N B A N Cover plate I Cover plate Pin Pos.2 Starting position N Pos.1 Pin Pos.2 Starting position I Pos.1 Fail-safe position: Valve open without supply pressure Orientation of cam disc when control valve closed, additionally apply actuator with maximum signal pressure Direct operating direction Connection: Output 138 Reverse operating direction Connection: Output 238 Refer. variable Sig. press. Valve Cam Refer. variable Sig. press. Valve Cam Decreases Decreases Opens B Increases Decreases Opens A N B I Cover plate A N Cover plate Pos.2 Pos.1 Pos.2 Pos.1 Pin Starting position I Pin Starting position N Fig. 5 Aligning the cam disc for single-acting rotary actuators with spring return mechanism EB 8386 EN 11
I N I Attachment to rotary actuators Double-acting rotary actuator with spring-return mechanism Cam disc linear (standard) Orientation of cam disc when control valve closed, additionally apply actuator with maximum signal pressure Control valve opens counterclockwise (increasing pressure to y1, decreasing pressure to y2) Direct operating direction Reverse operating direction Refer. variable Signal pressure Valve Cam Refer. variable Signal pressure Valve Cam Increases Output 138 to y1 Output 238 to y2 Opens A Decreases Output 138 to y2 Output 238 to y1 Opens B N B A N I Pin Starting position N Pin Starting position I Control valve opens clockwise (increasing pressure to y2, decreasing pressure to y1) Direct operating direction Reverse operating direction Refer. variable Signal pressure Valve Cam Refer. variable Signal pressure Valve Cam Increases Output 138 to y2 Output 238 to y1 Opens B Decreases Output 138 to y1 Output 238 to y2 Opens A A N N B I Pin Starting position N Fig. 6 Aligning the cam disc for double-acting actuators Pin Starting position I 12 EB 8386 EN
Attachment to rotary actuators Aligning the cam disc: Important! For the alignment of the cam disc according to Figs. 5 and 6, the valve must be closed! For actuators with fail-safe action "Valve OPEN without supply pressure" and for springless actuators, the actuator must therefore be loaded with max. signal pressure prior to aligning the cam disc so that the control valve moves to closing position. Loosen clamping screw (3.1, Fig. 4) of the coupling lever (3) a little so that the cam disc can be rotated together with the positioner shaft. Turn cam disc including the selected cam A or B such that the fulcrum of the cam disc, the marking point and the black pin are aligned (Figs. 5 and 6). Hold cam disc firmly and tighten the clamping screw (3.1). To turn the cam disc over, insert an Allen key into the positioner shaft for counterhold, so that the fastening nut is loosened and removed together with the cam disc. Subsequently, remount the cam disc with its backside. Default setting is shown in Figs. 5 and 6 on the top left: valve closed in fail-safe position, opens counterclockwise and closes clockwise. 3 Connections 3.1 Pneumatic connections Depending on the cover plate, the pneumatic connections are either 1/4-18 NPT or ISO 228/1- G 1/4 tapped holes. The supply input Supply 9 is equipped with a sintered metal filter (Order no.: 1400-6897), the other connections are equipped with sieves (Order no. 0550-0213) to prevent dirt collecting in the device. To clean or replace them (if necessary), remove the cover plate. For the connection, you can use commonly available male connections for metal and copper tubing or plastic tubes. Caution! The supply air must be dry and free of oil and dust. Always observe the maintenance instructions applying to the upstream pressure reducing stations. Thoroughly purge all pneumatic lines before you connect them. Important! The supply air pressure should be set to 0.2 bar above the upper bench range value of the actuator (see nameplate). 3.1.1 Pressure gauges Besides pressure gauges, you require a gauge mounting block to control the supply air (Supply) and signal pressure (Output). The existing connecting plate must be replaced with the gauge mounting block. EB 8386 EN 13
Attachment to rotary actuators Accessories Gauge mounting block: G 1/4 NPT 1/4 Pressure gauge (SS/Brass): 1x Supply, 1x Output for single-acting 1x Supply, 2x Output for double-acting Order no. 1400-7611 1400-7612 1400-6950 1400-7613 3.2 Electrical connections Electropneumatic positioner: The reference variable transmission lines must be connected to case terminals +11 and 12 via the cable gland. For versions with limit switch, you must additionally connect their wires to the terminals 41, 42 and 43. For electrical installations, you are required to observe the relevant electrotechnical regulations and the accident prevention regulations of the country in which the instrument is to be used. In Germany, these are the VDE regulations and the accident prevention regulations of the employers liability insurance. For installation in hazardous areas, EN 60079-14:1997 and VDE 0165 Part 1/8.98 apply. For connection of the intrinsically safe circuits, the data specified in the Certificate of Conformity or the EC Type Examination Certificate applies. Warning! If you change the electrical connections between control signal and limit switch, explosion protection can no longer be guaranteed. Do not loosen screws sealed with paint inside or outside the housing. 14 EB 8386 EN
Attachment to rotary actuators Note for selecting the cables and lines: If you are routing several intrinsically safe circuits in one multi-core cable, you are required to observe paragraph 12 of EN 60079-14 and VDE 0165/8.98. Note especially that for commonly used insulation materials, such as polyethylene, the radial thickness of the conductor insulation must be minimum 0.2 mm. The diameter of a single wire of a flexible conductor must not be smaller than 0.1 mm. The conductor ends must be protected against unlaying, e.g. by using wire end ferrules. When two separate cables are used for connection, an additional cable gland can be installed. Unused cable entries must be sealed with caps. Accessories Cable gland M20 x 1.5 Black Blue Order no. 1400-6985 1400-6986 Adapter M20 x 1.5 to 1/2 NPT: Powder-coated aluminum 0310-2149 Metal cable gland for temperature below 20 C 1890-4875 Plug connector according to DIN 43650: for reference variable for microswitch 1400-7603 1400-7603 Limit switch (retrofit kit) 1400-7602 Conversion kit to IP 65 1790-7408 +11-12 41 42 43 Control signal 4 to 20 ma only electropn. version Optional limit switch Fig. 7 Electrical connection EB 8386 EN 15
I I Operation Adjustment 4Operation Adjustment 4.1 Starting point and reference variable Note! The positioner is delivered already set by the manufacturer. The pre-determined fitting position of the tension spring (4) is marked by a spot of paint and should not be changed. Note! Electropneumatic positioners with tight-closing function are equipped with a slide switch on the printed input circuit board to activate/deactivate this function. Important! The activate and deactivate function must be switched off while zero is adjusted. Only after zero has been adjusted can the relevant function be activated on the switch. If the reference variable is, e.g. 4 to 20 ma (0.2 to 1 bar), the required rotary angle for opening or closing the control valve determined by the cam disc must travel through its full range. The starting point is then 4 ma (0.2 bar) and the final value is 20 ma (1 bar). Version without tight-closing function Potentiometer span Important! The adjustment of zero is always referred to the closing position of the valve. Therefore, it depends on the version of the actuator used how zero is adjusted, e.g. for a version with reverse operating direction, the zero point is set to 20 ma (1 bar) instead of 4 ma (0.2 bar). The exact starting point is adjusted via the zero adjuster (3) (Fig. 2). The upper range value results from the angle of rotation of the cam disc automatically. If, however, a correction of the upper range value should be necessary, it can only be altered slightly via the potentiometer span of the electropneumatic positioner. Turn it counterclockwise to reduce the span and turn it clockwise to increase the span. Version with tight-closing function Potentiometer span Fig. 8 Adjuster A A N N OFF ON 16 EB 8386 EN
Operation Adjustment Connection With electropneumatic positioners, connect an ammeter to the terminals +11 and 12. With pneumatic positioners, connect an air pressure source providing max. 1.4 bar to the control signal input (input 27) via a pressure transducer and a pressure gauge. Connect compressed air to the supply input (Supply 9). 4.2 Adjustment 4.2.1 Actuator version: Valve closed without supply air Important! To ensure that the entire closing force can be effective in the control valve, the actuator must be completely vented when reaching the lower (direct operating direction) and the upper (reverse operating direction) range value of the reference variable. Therefore, set input signal to a slightly increased starting point of approx. 4.5 ma (0.225 bar) when the operating direction is direct, and to a slightly lowered starting point of 19.5 ma (0.975 bar) when the output signal is limited to a range of 4 to 20 ma. This applies in particular to controllers and control systems whose output signal is limited to 4 to 20 ma. For electropneumatic positioners with tightclosing function, the lower and upper range value can be set to 4 respectively 20 ma. The activate/deactivate function ensure the closing position. Example: When the operating direction is direct, the control valve must pass through an opening angle of 90 (90 -cam disc must be installed) with a reference variable of 4 to 20 ma (0.2 to 1 bar). The valve opens as the reference variable increases. Starting point (zero) 4 ma (0.2 bar) 1. Set input signal to 4.5 ma using the ammeter (or the pressure adjuster to 0.225 bar). 2. Turn the zero adjustment screw (3) until the plug stem of the valve just begins to move from the resting position. 3. Decrease input signal and increase again slowly. Check whether the plug stem starts moving at a starting point of 4.5 ma (0.225 bar). 4. Correct any deviations by turning the zero adjustment screw (3). NOTE for adjustment with reverse operating direction: For reverse operating direction (Fig. 5 top right), the zero point (Valve closed) must be adjusted at 20 ma (1 bar). The upper range value (Valve open) will then be 4 ma (0.2 bar). EB 8386 EN 17
Operation Adjustment 4.2.2 Spring-return actuator version: Valve open without supply air Important! In this fail-safe position, the actuator must be loaded with a signal pressure that is high enough to tightly close the valve, even when upstream pressure of the plant does prevail. The upper range value of the reference variable must be 20 ma or 1 bar (direct operating direction) or the lower range value 4 ma or 0.2 bar (reverse operating direction). The required signal pressure should be approx. 1 bar above the upper bench range value of the actuator. Example: When the operating direction is direct, the control valve must pass through an opening angle of 90 (90 -cam disc must be installed) with a reference variable of 4 to 20 ma (0.2 to 1 bar). The valve closes as the reference variable increases. Starting point (zero point) 20 ma (1 bar) 1. Adjust input signal to 20 ma (1 bar) using the ammeter or pressure adjuster. 2. Turn the zero adjustment screw (3) until the plug stem just begins to move from its initial position. 3. Increase input signal, then slowly decrease and check whether the control valve starts moving at 20 ma (1 bar). 4. Correct any deviations at the zero point adjustment screw (3). NOTE for adjustment with reverse operating direction: For reverse operating direction (Fig. 5 bottom right), the zero point (Valve closed) must be adjusted at 4.5 ma (0.225 bar). The upper range value (Valve open) will then be 20 ma (1 bar). 4.2.3 Double-acting actuator: Valve opens counterclockwise and valve opens clockwise Example: When the operating direction is direct, the control valve must pass through an opening angle of 90 (90 -cam disc must be installed) with a reference variable of 4 to 20 ma (0.2 to 1 bar). The valve opens as the reference variable increases. Starting point (zero point) 4 ma (0.2 bar) 1. Set input signal with ammeter to 4.5 ma (or pressure adjuster to 0.2 bar). 2. Turn zero adjustment screw (3) until the plug stem just begins to move from the resting position. 3. Decrease input signal and increase again slowly. Check whether the plug stem starts moving at a starting point of 4.5 ma (0.225 bar). 4. Correct any deviations by turning the zero adjustment screw (3). 18 EB 8386 EN
Operation Adjustment NOTE for adjustment with reverse operating direction: For reverse operating direction (Fig. 6 on right), the zero point (Valve closed) must be adjusted at 19.5 ma (1 bar). The upper range value (Valve open) will then be 4 ma (0.2 bar). Important! After adjustment of the positioner, close it by reattaching the cover. Make sure that the vent plug in the case cover faces downwards when the control valve is installed in the plant. This helps to prevent condensed water from collecting in the positioner. EB 8386 EN 19
I Adjusting the limit switch 5 Adjusting the limit switch Versions equipped with a limit switch can issue signals to indicate the travel end position. The rotary movement of the plug stem is transmitted via actuator, positioner axis and cam disc (1) to the limit switch. The limit switch can be adjusted to provide a signal when the valve has reached one of its end positions (closing or opening position). Adjusting the switching point: Prior to adjusting the limit switch, the starting point and the upper range value of the positioner need to be adjusted. 1. Move valve to the desired end position where the switching function is to be activated. 2. Loosen screw (3) and turn plate (2) so that the roll (4) of the limit switch (5) releases the switching contact at the respective cam (1.1) of the cam disc. 3. Tighten screw (3) and check switching point once again. 1 Cam disc 1.1 Switching cams 2 Plate 3 Screw 4 Roll 5 Limit switch 1 1.1 2 A N 41 42 43 Switching contact 3 4 5 41 42 43 Fig. 9 Limit switch operation via the cam disc 20 EB 8386 EN
Servicing explosion-protected devices 6 Servicing explosion-protected devices In the event that a positioner s part on which the explosion protection is based must be serviced, the positioner must not be taken into operation again, unless an expert has inspected the device according to the explosion protection requirements, has issued a certificate stating this, or has equipped the device with his mark of conformity. Inspection by an expert does not have to be carried out, if the manufacturer performs a routine check test on the device prior to taking it into operation again, and the success of the routine check test is documented by attaching a mark of conformity to the device. Explosion-protected components must only be replaced by original manufacturer components which were subjected to a routine check test. EB 8386 EN 21
Dimensions in mm 7 Dimensions in mm M20x1.5 129 88 15 28 28 28 Supply Input Output 2 Output 1 Pneumatic connections G1/4 or NPT 1/4 22 EB 8386 EN
EB 8386 EN 23
24 EB 8386 EN
EB 8386 EN 25
26 EB 8386 EN
EB 8386 EN 27
SAMSON AG MESS- UND REGELTECHNIK Weismüllerstraße 3 60314 Frankfurt am Main Germany Phone +49 69 40 09-0 Fax +49 69 40 09-15 07 Internet: http://www.samson.de EB 8386 EN S/Z 2004-07