[No 732 INSTRUCTION 1988) [ Book f NS-732 AUTOMATIC INDICATING CONTROLLER NAKAKITA1. Outline This controller can be applied to all possible fields of process control such as pressure, diferential Dressure, temperature liquid level, flow rate, viscosity ete. when used in combination with diaphragm control valves at the operating end. It is a pneumatic controller which can automaticaly regulate various process conditions at the optimum level, {t's constructed compactly and weight light, incorporating least possible number of parts. Its control, handling and maintenance is therefore simple and yet it hat considerable durability. It is an inswes ment most sutsble not only for fixing on graphic panel but algo for local control, having usages in versatile felds, For vious warsmites and For direct temperature direct presuredetartion getction Stesita ee fps” ate Model nS P732 Mosel NS TM 722 2. Construction and specification 1. Construction Specifications 1) Control air pressure output): 0.2~1. Oke/an* 2) Supply sir press 1. dkg/en? 3) Control operation Proportional band : 10 250% Reset time 20 ~0.1 Min. (std) Rate tim 10 ~ 0.06 Min, 4) Both direct and reverse action are avilable 5) Accuracy: Within 1% of full seale 6) Method of fixing: Panel mount or wall mount Type. 7) Casing: _Drip-proof and dust-proof type 8) Weight: ca. Skg. (When detecting ment is thermo bulb,ca. kg) 9) Airconsumption: Normal: 1N@/min. Maximum : 30N€ /min. 10) Connection for control and supply air: PT 1/4 11) Pressure measuring connection: PT 1/43. Performance 1. Reaction When measured value becomes higher than the set value (deviation), the upper end of proportional lever shifts to the right. Thus the flapperapproachesto the nozzle and the back prossure of nozzle ie, the pressuce charged upon pilot realy, increases. Consequently valve in pilot relay opens end supply pressure flows into control side to ineresse the pressure. At the same time, this pressure in charged upon propertional bellow and lifts up proportional lever Prop. a and thus flappe is detatced from the rozze nd contol Risction. pressure is set in proportion to such deflection. All of the Moreid sections ocsure smuitancousy in the sctual i droraon “hen to cron ove lator") contro! pressure becomes Jem? (intermediate point KS trol pressure becomes 0.6 ka/em2 (intermediate point of 0.21.0 kalem2) Flapper: nozzle Feedback sprin Proplover cae Pilot relay Diaphragm Pilot valve VO \ Noritice 2.1. action Orifice cleaning push button Assurming that the controller js acting properly and measured value and set value are in equilibrium, (that is, the deviation ie “O”), and the same pressure as control pressure is sealed in the proportional bellows andt-reset bellows. If messured value bacomes too high as in the above cas, Paction Immediate: ly takes place and control pressure increases. Thus control pressure flows into the reset bellows ‘through reset throttle valve. [As the pressure inside raset bellows increases, proportional lever comes down and flapper approaches 10 the nozzle and back pressure increases. Conseauently pilot relay valve in opens 10 Increase the control pressure and the increasing pressure inside pro- portional bellows lifts up the pro- portional lever and causes the Tapper to detatch from the nozzle ‘again, This resetting etect con ‘inues until control pressure in creases to such extent that the control valve opening enables the reversion of measured value to the FI#PPer— Reset chamber sot value (that is, until deviation nozzle ‘becomes ero} Pressure of propertional bellows | = -Exhaust hole ‘and reset bellows thus balances and the original balance condition Is established. Pilot relay Prop. lever | f 7 oe valve Orifice cleaning push button3.P.LDaction Rate throttle valve and rate bellows chamber are connected in parallel between the pilot relay and Proportional bellows. In the aforesaid , end PI. action, the inside pressure of proportional bellows is In proportion to the amount of deviation. Therefore, when the measured value changes, control Dressure flows in or out with the speed corresponding to such changes, o that the pressure inside the Proportional bellows will synchronize with the change of measured value, Since the pressure reduction taking place as it passes through the rate throttle valve is in proportion to the speed of fluctuation of measured value, pilot relay output ie., control pressure also becomes larger or smaller than the Internal pressure of proportional bellows to the oxtent of the differential pressure at the rate throttle vale. Rate bellows chamber is provided to transmit contro! presure to the proportional bellows utilizing ‘the volume change of rete bellows caused by its elasticity and to give stability the system, Therefore, when rate action is utilized, control valve opening can be adjusted more quickly and it Certainly gives convenience especially to the process where time lag is great. Daaction Reset time dial Indicating Setting knob Rate time dial woanSienn GS (2) Sit ballon chantar est Exhaut hole cy yn Reset chamber ) Prop. _Measating pointer (Black) lever 1@ Mesturing pressure Spiral Bouldon tube Air supply = 2 Indicating scale Control pressure Two elements CsuP/conT»e.s. /4, Installation 1. Controller Please install i at the place where it is least affected by temperature, humisity, dust and vibration. ‘When it ig installed at the place where vibration is unavoidable such 2s in 8 ship, vibration should be within such tolerance that the total amplitude of measuring pointer and two slements (sup/eont) pressure gauge pointer are within 1 graduation of the scale. 2, Pressure leakage of air piping and joints When ther i leakage at the connecting jaints of the piping, perfect regulation is not possible. Therefore sfter completion of piping, conduct complete leakage test. Especially make striet checking ofthe joint between controller and control valve 3, Measuring unit “The temperature of detecting fluid comes to this measuring unit should not exceed 80°C. In the case of steam, provice a siphon tube in order to lead the cooled drain to the controller. When pressure pulsates, provide noise damper or noise dampner and when detecting piping vibrates, provide ‘exible tube in the detecting pipe. 4, Temperature measuring unit (Thermo Element) 1) Do not install the thermo bulb in the pipe line of which has high speed of flu. If the flow Is too fast, It gives undue stress on the mechanical strength of the measuring part. “Therefore ordinary piping flow rate is appropriate. Effective length of insertion must be more then 70%. 2) Pleave be care not to twist or pull capillary tube or it it against hard object when it is installed. To turn the connecting screw, loosen the union nut first. Do not twist the capillary tube when connecting serew is turned. install capillary tube at a safe place so that it does not get damaged. Moreover, capillary tube should be installed firmly without any needless trembles (Method of fixing temp. measuring unit Screw type Flange type Effective length of insertion = more than 70% of total length 7 Connection sre capitiary tube ne SS CHT ES cI ( Union nut Thermo Well5. Air supply and connection N Air supply main pipe 00 6 cur : | eae supine J) tee sal A contoter 87706 Fer reguletor \ | To control valve 1. Supoly air source Pressure of supply air should be 3- 1Okg/em®? and air should be free from scales and oliness. In eny {ason of at any time of the day there should be no drain in the pipe. For piping, use white gee poe o- copper pipe. Stop valve must be BC stop valve. Install supply air main pipe as close oe posible to the controller. Before connecting it to the controller, pas air of about 2kg/em? through the pipe to reams scale and drain, Signal control circuit O20 (6 * It copper pipe is usually used. When corrosion resistance and seamless pipe are required, vinyl oF polyethylene or nylon tube are applied. But since these plastic tubes lack heat resstanoe end ‘mechanical strength, provide appropriate protection. Piping should be install for the shortest distance in prinetple Use long pine and minimize joints so that maintenance and inspection are eaty. Leakage will affect securacy of control. Therefore prevent leakage by all means. Leakage test 's conducted by setting filter regulator at 1 kg/cm? and pressurize the entire circu and check each connection with soap water 3. Connection of controlter (Back side) Pressure measuring unit Temperature mesturing unit, ‘Measuring Connecting terminal PT 1/4 Measuring Air supaly Control press (Out Pur)6. Preparation for operation Check again if the adjusting devices are properly installed according to the plan. Also check if they function properly. To change it into automatic control from manual control, be care not to disturb the process. 1.Steps for change over from “Manual” to “Auto” 1) Fully close front and rear stop valves of the control valve and by-pass valve. 2) Sand supply air to the controller. +3) Gredually open the by-pass valve and while watching the movement of pointer of the controller, bring the measuring pointer closer to the setting point. 4) Fully open a rear stop valve of the control valve. 5) While watching the action of control valve, gradually open the front valve and simulteneousty close the by-pass valve. If valve opening is changed too radically, balance of the process is distrubed and it ean not be stabilized. 2. NS743"Auto/Manual selector ‘Auto/manual selector is attached below the NS 732 Indicating controler. It is used for the manual control atthe start of the operation or for checking of controller or for repsiring. I-can be adjusted manually without stopping the operation of the control valve. 1) Control of change-over cock (Auto- Manual Selector) AUTO (Automatic control) ‘Controt pressure coming from controller is charged upon the control valve through the change-over cock. It is adjusted automatically MANUAL (Manus! control) Control pressure which was set by the filter regulator at an optional position will remoteccontrol the opening of control valve through this change-over cock. In the ectual operation, adjust the ragulator while watching the measuring pointer of the controller so that the objective value can be maintained Control valve becomes fully open —~ fully close in accordance with the movement of SUP/CONT. pressure for the span of 0.2 1.0 kg/em? and 50% opening is obtained at the indication (of 0.8 kg/em2, 3) Control of AUTO and MANUAL ‘Transition from manual control to automatic control. A. The pointer of AUTO of two elements (SUP/CONT) pressure gauge starts to move when the measuring pointer of the controller is made to overlaps the setting pointer by manual control. 1B. Then gradually it shifts in the same direction as AUTO pointer and at the instance when the latter matches with the MANUAL pointer set the change over cock to AUTO. Transition from automatic control to manual controt Match the MANUAL pointer with AUTO pointer of two elements (SUP/CONT) pressure gauge ‘by operating the regulator for manual control and then set the changeover cock to MANUAL. Note: Before changing over from MANUAL to AUTO or from AUTO to MANUAL, be sure to control the change-over cock to that the pointers of AUTO and MANUAL of two elements (SUP/ CONT) pressure gauge will overap. If this ie not done beforehand the operating of the pointer may cause temporary disturbance ofthe process. 2 AUTO MANUAL, 8132 Indicating Controller ‘Two elements (SUP/CONT) To control valve ‘pressure gauge ‘connecting thread PT 1/4 female, @ form control pressure of controller. to control valve © Supply air7. Adjustment for operation 1. How to do adjustment ‘8: Proportional band control dial Ci Rett time dial Remarks: In case no rate function is provided, ‘apply the plug at the rate time dia A. Setting knob ‘Sot the setting pointer (red) to the desied graduation on the scale by setting knob. 8. Proportional band control dial ‘The smaller the value on the dial (.., Proportional band becomes narrower), it bacomes sensitive. But if it becomes too sharp, hunting occurs. When the value on the dial becomes too large (pre, Portional band becomes wider), sensitivity becomes dull, If it becomes too dull, devietion of ‘measured value from the set value, in the ease of load change, becomes excessive: CC. Reset time dial \When reset time is shortened, the time required for balance point is shortened, But when it becomes {00 short, stability is lost end it apts to cause hunting. When reset time is made too long, it consurmes too long time before balance is established at the set value. ©. Rate time dial (This dial isnot given in the case of proportional +intogral ection) {is used for the process which involves much time lag. It controls the process ahead of the control sction of the system in order to off-set the time lag (delay). When rate time is made too long {to ‘much lead) it causes hunting. Whereas if ft is too short, satisfactory effect is not obtained. . Change over of direct-everse action Direction of operation of control valve is determined by the nature of the process. It is determined by whether the control valve is a direct operation or a reverse, For example, in the case of the above Photograph, it acts in Reverse. To change the set up into Direct action (i.e. the action where increase of input causes increase of outputl, turn the proportional dial to the right for 3/4 turns 2. Adjustinent The optimum adjustment of controller can be obtained by the following steps, 1) Set the reset time dial at max. (20 min.) and when there isa rate time cial, so at minimum value 2) Starting from 250%; gradually reduce the proportional dial rom 250% to 10%, while checking the Fesult of adjustment, It eauses hunting when it comes toa certain proportional zone, The optimum Value is at 2- 4 times of such proportional zone 5} Gradually reduce the reset time by turning reset time dial. When it becomes les than the marginal value, it causes hunting, So reverse it slightly from such point and then fix It 4) Fix the rate time gil at about 1/4 of the ukimate reset time or about 1/2 of the time delay of the Process and control devies. In this case, proportional zone can be made ightly smaller8, Maintenance When the controller is installed properly, perform the following maintenance periodically accordingtoa preset program. TT Remove drain deposited in the air supply tube by loosening the drain plug et the bottom of filter regulator. 2. Be. care to maintain the supply alr pressure always at 1.4 kg/em2g. When the performance of filter regulator is unstable, pair or replace It {3 According to the conditions of supply air, inspect the orifice holes of nozzle Detoile of Pilot Relay cf plot relay. Push button for orifice cleaning ,Orifice (rote hele 0.2mm) 1) ln case when orifice is clogged. Press the orifice cleaning push button to clean it. When it is necessary to take out orifice out of pilot relay, disassemble It according to the follow ing procedures. a. Stop sir supply to the controler bi, Carefully remove the entire orifice at the left end of the pilot relay by a spanner. ce. After taking off the orifice, clean the surface with thinner etc. if ol! (oF grease in sticking to it. Dry thus disassembled orifice and then re: came \denifcation mark for ossembling -2}When the nozzle in clogged, disassem- bile and clean according to the follow ing procedures. @, Same as 1) 8. above. '. Carefully disassemble nozzle clean- ing plug of proportional dial by a driver. , Clean the nozzle with a wire having ‘thickness of less than 0.4mm. d. Clean dusts ete. deposited on the flapper surface (to which the nozzle is contacting). Exhowst Control pressure Details of Nozzle and Flopper Proportional band del Nozzle back presure None (htile hole Om) Flapper9. Troubles, investigation of causes and counter-measures {or tubes) inside the con- troller. Troubles Causes Countor measures ‘When it does not increase. (1) Supply alr pressure is ab- | (1) Adjust it into normal con: normal ditions. (2) Orifice of pilot reley is | (2) Press the cleaning push clogged. button, (3) Leakage at the air piping | (3) Adjust it into normal éon- Sat output side (due to ditions. cracking), oF leakage at soldered joints or damage of iaphragm of control valve, (4) Inferior connection (or dis-| (4) Adjust it into normal con- connection) of link systems ditions (CONTROLLER! inside the controller. Output air pressure of con-| (5) Leakage of various pipings | (5) Replace the tube. troller does not increase or (tubes) inside the controtler, decrease inspite of the change | (6) Damage of element at (of detection input, rmeasureing part. (6) Replace element. When it does not descrease, (1) Nozzle at the flapper is | (1) Clean it with a wire of clogged. less than 0.4mm. (2) Clogging of piping from | (2) Adjust it into normal con- pllotelay to nozzle (break ditions down of tube). {3) Loosening of pilot relay | (3) Retighten it. orifice. (4) inferior connection (or ais-| (4) Adjust It into normal con- connection) of link mech- ditions, ‘anism inside the controller. (5) Leakage at various pipings | (5) Replace the tube. (CONTROL VALVE) Control valve lift does not change due to the increase ‘or decrease of ouput pressure of controtier o 2 Sticking of valve guide and valve stem, When positioner is provided sticking of positioner pilot. Disconnection of diaphragm] stem and positioner. Inspeetion by disassembly. When welding so foreign matters are caught into the repair any posible damage. a 2) oF other Parts, remove them and Repair the damage caused Dy sticking using Fine mesh, grinding paper or file, Adjust it into normal eon ditions. (FILTER REGULATOR) Pressure does not increase ‘even when setting knob is turned to increase pressure. Or pressure increase is abnor: mal or pressure does not go down. When pressure doas not increase, (1) ang (2) Replace the parts (1) Damage of diaphragm. | (3) Repair the damage caused (2) Damage of setting spring. by sticking using fine mesh (3) Sticking of pilot valve grinding paper or fie (4) Leakage at sir piping at | (4) Adjust it into normal | secondary side conditions. When pressure does not come down (1) Sticking of pilot valve (1) Repair the damage coused by sticking using fir (2) Clogging of exhaust hole grinding paper or file, lof the cover (2) Clean it.10. Correction of measuring link Measuring pointer is driven by the link connected to the measuring element. Before beginning correction, check if the moving parts of this unit move smoothly and lightly m 1. Thee basic adjustment. (1) Zero adjustment: Shift the entire scale by the same band, It means that the point of ‘origin is changed but inclination and shape of the curve do not change. (2) Adjustment of amplification ratio: It changes the slope angle of the ‘curve without changing the shape or point of origin of the curve. (3) Angle adjustment: Point of origin is unchanged but the shape of the curve is changed. That ‘means the change of indication at both tends of the scale is made steeper or flat. « eaing of control inant ° True value 00% (1) Zero point adjustment This Is the most common adjustment which is performed by fine tuning screw (B) of measuring. element. (2) Adjustment of amplification ratio Ratio of length of (C) and (0) levers is changed, In the actual practise, itis performed by the fine tuning screw on the (C) lever. (3) Angle adjustment The length of the link, (B) & (6) is adjusted by loosening the set screw (F), so that the (C), (D) levers and measuring link (E) make right angle at the median point of the full scale Procedures of correction 1, Conduct anget adjustment (3) by calculating the measured value corresponding to the median reading ofthe scale. 2, Conduct zero adjustment (1) by calculating the measured value corresponding to the reading of scale. 3, Conduct amplification ratio adjustment (2) by calculating the measured value corresponding to the ‘maximum reading ofthe scale 44, Repeat the steps 1, 2 and 3 above until satisfactory result is obtained. 5. Check the values at serveral readings of the scale. Do angle adjustment if necessary, but iti rarely needed C710.11. Adjustment of controller ‘Since the adjustment of controler i accurately done at the manufacturing plant when it is essembled, 40 not touch adjusting screw of respective link and lever unless it is absolutely necessary. Disassembly ‘of proportional and reset bellows should be absolutely refrained from, Hereunder are given the procedures of on the spot adjustment and checking of this Instrument. The purpose of this adjustment is to bring the function pin (2) on the proportional lever (1) on the tame vertical plane with the nozzle flapper setting shaft (3) (proportional dial shaft), so that control presture ‘does not change even when proportional band is altered when the controller Is operating in equiliarium conditions (ie., when control pressure i stabllized). |. Set the supply air pressure at 1.4 ka/em2. 2. When control valve is not connected the CONTROL side, apply PT 1/4 plug to the connection hole. When ithas NS 743 Auto/Manusal selector, set it to MANUAL, 3. Loosen the adjusting screw (4) of mesuring link and retighten the measuring pointer at the central position of indiesting dia 4, Turn the setting knob (5) to make the sotting pointer overlap with the measuring politer at the center of indicating scale, By turning the fine tuning knob (10), make the pointer set plates (6) and (7) completely overiap with restitution levers (8) and (9) when they are viewed from the front, and the pointer of restitution lover becomes roughly vertical atthe center of the scale, ‘5 Turn the reset cial to the right unti it hits the stopper and then looten the set serew iat the center of dial for 3- 4 turns, ‘Then draw out the knob straight forward, turn it to the left for 90° and tighten the screw again, 6. Tur the reset dial anti-clockwise until it hits the stopper. When it has the rate dial, turn it to the left until the stopper is engaged. 7, Disassemble the stopper (11) of proportional band. 8, Set the proportional dial at around 60%, and turn the setting knob to the right and left and maintain ‘the control pressure at 0.6 kg/em2. Then loave it for sometime to see how it setties and repeat adjustment until equilibrium is established, When reset dial is turned to the right under such con: ditions, reset valve will fully close before it hits the stopper because itis in the course of shifting according to step 5) above. In such case only lightly tighten it by finger tip. By this adjustment, (0.6 kglem? air is sealed into the reset bellows and it functions in the same way as P.action. When ‘the system performs Praction only, (When it has no reset) the aforesaid adjustment is not necessary. . Sot the mark at the center of the dial of proportional band to indicator (12), then the proportional cm.10, nh 12. 13, bband becomes infinitely large and even when setting pointer is shifted for full scale by turning the setting knob, variation of control pressure shall remain to be minimum. The system is so adjusted a8 above at the plant, But just for confirmation sake, try it again to see if itis s0 set, under such Conditions, turn the fine tuning ssrew (13) on the proportional lever to set the control pressure at 0.6 kg/om2, Make both pointers completely agree at the center of the indicating dial. (If possible fix them by Celophane tape, ete.) Then turn the proportions dial to the right and left and adjust it with fine ‘tuning screw (14) in such way that the control pressure indication moves to both tides of the mark for even distance; for example, at Direct 10% control pressure becomes 0.3 kg/em? and at reverse 10% it also becomes 0.3 kg/em2, [Adjust the fine tuning serew (13) located at the mark of proportional lever to set the control pressure at 0.6 ka/em2, Then at 10% position (either Direct or Reverse, in the case of Reverse, driver shal ‘ot fit in unless itis at around 25%) set the control pressure at 0.6 kg/cm? also by using fine tuning Screw of the flapper (3). Repeat this procedure until the control pressure becomes 0.6 kg * 0.035 fem? at any point of the ial This will completes the adjustment. But once again check it by the steps from 6 to 11. Lastly return the reset dial to the original positon, ‘Turn the reset dial to the left until ithits the stopper and loosen the set screw and draw out the dial. Then pick up the reset dial shaft by finger and turn it to the right until it stops end turn it back 4 little. The point where the set mark of the shaft mests the set mark on the circumference, Is the point of longest reset time (20 min.). So set the dial eccordingto theindication.12. Order of disassembly If by any chance this instrument should be damaged, you can disassemble the unit and repair or ex chenge the damaged parts as far as such damage occurs to the following 2 parts, If trouble occurs to the parts other than these three, please do not disassemble or repair it by yourself but inquire our ‘company about it or send it to us for repair or repair it under the presence of our service engineer. When Bouldon tube is damaged. 1) Stop the air supply to the controller. 2) a. Close the main valve of the instrument when damage occurs to the pressure controller. b, Remove temperature measuring terminals when damage occurs to the temperature controller. 3) Open the cover of the unit and remove two screws and dismount the scale plate. 4) Confirm that at left underneath of the instrument is the mechanism shown in Fig, 1 oF 2. Fig. 1 Pressure controller Fig. 2 Temperature controller 5) a. When it Is the pressure controller, disconnect the joint of “a” ink, by removing the locking band. ‘Then remove 2 screws “b" and “” by a driver. Then Bouldon tube can be easly removed. b. In the case of temperature controller, disassemble the connection of “a” link by removing locking bband, Then you can see the terminals of 4 seraws b. Remove these screws from the back side lof the casing. Then you can eatily dismount the Bouldon tube. 6) Fx anew Bouldon tube in the reverse order of the above, 7) Perform the adjustment of scale plate according to the procedures described in “Item 10. Correction of Measuring Link”.2. When two elements (SUP/CONT) air pressure gauce is damaged. 1) Reduce the supply air pressure to O kg/cm? by the filter regulator. 2) 2, In the case of the temperature controller, disconnect the joint of air pipe at the back of the casing. b. In the case of the pressure controller, first close the pressure detecting main valve end them disconnect the air pipe joint and presture detecting pipe joint at the back side of the casing. 3) Open the cover of the instrument, remove 2 screws and disassemble the scale pl 4) Confirm that at right underneath ‘the instrument is the mechanism 2s shown in Fig. 3. 5) Take off the two clips which Is fixing the black hyparon tube ‘and disconnect the joint of the ‘tubs. At this time pay attention ‘not to damage the elasticity of the clip, Then remove 4 screws “al” and lift the pressure gauge straight upward, then it comes off easly 6) Fix the new pressure gauge in the reverse order of the above. 3. When the diaphragm inside of the pilot relay is damaged, 1) Stop air supply to the eontrolie. 2) Open the cover of the instrument and confirm that the mechanism shown in Fig. 4 exists atthe right center ofthe instrument. 3} Remove 2 screws "A’ 4) Thea itis possible te dismount the unit of pilot relay from the reversing mechanism as shown in Fig. 5 5} Pilot out as lay unit ean be take lustrated in Fig 6, when "shown in Fig. 5 two screws are removed, 6) Assembly is done in the reversed order of the above,