Series MP Mini-Photohelic® Differential Pressure
Contents
1. Series MP Mini Photohelic Differential Pressure Switch Gage Specifications Installation and Operating Instructions Bulletin B 37 A l 5 PI Wig LOW PRESSURE PORT o SERAN E joja 112 Ol ne 92 19 32 amp e 9 65 88 bd bes 3 1 16 v O i O Nc 1125 4 177 79 fe HIGH PRESSURE PORT 1 Ti l l 4 3 1 32 77 00 ely TEL 4 INCHES WC The Series MP Mini Photohelic differential pres sure switch gage combines the time proven Minihelic ll differential pressure gage with two SPDT switching setpoints The Mini Photohelic Switch Gage is designed to measure and control positive negative or differential pressures consisting of non com bustible and non corrosive gases Gage reading is independent of switch operation Switching status is visible by LED indicators located on the front and rear of the gage DWYER INSTRUMENTS INC P O BOX 373 MICHIGAN CITY INDIANA 46361 U S A 3 1 2 77 00 3 1316 96 84 H 9 32 7 134 SPECIFICATIONS GAGE SPECIFICATIONS Service Air and non combustible compatible gases Wetted Materials Consult factory Accuracy 5 of full scale 70 F 21 1 C Gage face mounted in vertical position Pressure Limits 30 psig 2 067 bar Temperature Limits2. 1 24 kPa or equivalent should be used only in the vertical position unless special calibra tion was specified when ordering Mounting The Mini Photohelic Switch Gage is normally mounted before making electrical connections Terminal blocks are located on the rear of the gage for electrical connections A Panel Mounting Standard installation for the Mini Photohelic Switch Gage mounting is flush through a panel Allow approximately 1 clearance for pressure tubing and electrical wiring cut a 2 5 8 66 68 mm diameter hole in the panel Insert the Mini Photohelic Switch Gage into the panel thread 6 mounting screws into the mounting lugs and tighten Fig A LOW PRESSURE PORT 2 19 32 id 65 88 q 3 1 16 1 na ays HIGH PRESSURE PORT 5 32 397 60 33 MOUNTING HOL TYP 4 PLACES 2 276 57 81 TYP be tase H114 2 11 16 68 26 SQ 49 21 4 37 Fig B AST NX 8 VA 1 0 4 Zeroing Before installation the Mini Photohelic Switch Gage may need to be zeroed before placing into operation If zeroing is required you must first remove the locking clip located near the bottom face of the gage refer to Fig B Use a small blade screwdriver or the allen wrench supplied with the Mini Photohelic Switch Gage to remove the clip The clip is attached with a hinge design so it will not get lost after removal After removing t
3. require the SP1 relay to energize Press pushbutton marked SP1 on the rear of the instrument SP1 LED located on the front and rear of the instrument will flash several times When LED stops flashing calibration is complete Repeat the same steps above for SP2 relay 8 Circuit Style The Mini Photohelic Switch Gage is available with several factory installed optional circuits They are identified by the label shown in Fig D This label is mounted on the upper side of the main pressure housing The letter H denotes a circuit in which the relay can be made to latch or remain energized after pressure increases above its setpoint The letter L denotes a circuit in which the relay can be made to latch or remain de energized after pressure decreases below its setpoint Two letters are required to fully identify a dual setpoint unit Thus circuit style HH which is standard is a dual setpoint circuit which has provisions for latching on pressure increase to either setpoint Circuit styles may be used with either setpoint stated above Fig D Dwyer MINI PHOTOHELIC MP CIRCUIT US POWER SUPPLY 24 VDC 24 VAC 50 60 HZ 4 WATTS lt A CONTACT RATING 5A 30 VDC 120 240 VAC 6 IND CONT EQ CAUTION PRESSURE M gt PSIG 207 kPa MADE IN U S A 9 Dual Setpoint Automatic Reset Circuit style HH is used for simple on off switching applications To place in service connect load circuits to the appropriate ter min
4. 20 to 120 F 6 7 to 49 C Process Connections Barbed for 3 16 D tubing STD 1 8 male NPT optional Size 4 1 8 104 78 mm depth x 3 1 16 77 79 mm diameter Weight 23 oz 652 g SWITCH SPECIFICATIONS Switch Type 2 SPDT relays Electrical Rating 5A 120 240 VAC Resistive 5A 30 VDC Electrical Connections Screw Type Terminal Block Accepts 22 12 AWG wire Power Requirements 24 VDC 24 VAC 50 60 Hz 4 watts Mounting Orientation Gage face in vertical position Set Point Adjustment Push Buttons Standard Accessories 2 mounting screws 1 050 hex allen wrench Agency Approvals UL cUL Phone 219 879 8000 Fax 219 872 9057 www dwyer inst com e mail info dwyer inst com INSTALLATION 1 Location Select a location free from excessive vibration and where ambient temperature will be between 20 to 120 F 6 7 to 49 C Pressure sensing lines may be any length necessary without affecting accuracy However long runs of tubing will dampen readings slightly and cause an increase in response time If pulsing pressure or vibration cause excessive pointer oscillation please con tact factory for ways to provide additional damping Position The Mini Photohelic Switch Gage is calibrated and zeroed with gage face in the vertical position at the factory If the gage is used in any other position it must be re zeroed each time the position is changed Gages with ranges under 5 in w c
5. als in Section C Fig C for SP1 relay and SP2 relay No connections are required in Section A 10 Dual Setpoint Manual Reset Circuit style HH may also be used for manual reset applications where it is required to maintain contact on either relay following pressure increase above its setpoint Load or signal con nections are made to the appropriate terminals in Section C as in step 8 Connect terminals in Section A through normally closed switches or pushbuttons as shown in Fig E Use dry circuit tyoe switches such as Dwyer Part No A 601 with palladium gold etc or rotary wiping action type contacts is recommended Fig E Circuit style LL is used for manual reset applications where it is required to maintain contact on either relay fol lowing pressure decrease below the setpoint Load or signal connections are made to the appropriate terminals in section C as in step 8 A normally open type manual reset switch such as Dwyer Instruments Inc Part No A 601 is connected to the terminals in Section A The cir cuit must be armed by momentarily energizing the switch while the pointer is to the right of the setpoint From that point on the circuit will latch on pressure decrease below the setpoint and remain latched on pressure increase until manually reset with the optional switch 1 High Low Limit Control Dual Setpoin
6. ge S17 SP1 Reset Terminal Do not apply power Section S17 SP1 Reset Terminal Do not apply power A S27 SP2 Reset Terminal Do not apply power S2 SP2 Reset Terminal Do not apply power Section Vs 24 VDC 24 VAC 50 60 HZ B Vs 24 VDC 24 VAC 50 60 HZ NO1 SP1 Relay N O Contact Ci SP1 Relay Common Contact Section NC1 SP1 Relay N C Contact C NO2 SP2 Relay N O Contact C2 SP2 Relay Common Contact NC2 SP2 Relay N C Contact a SECTION A a L SECTION C SECTION BH bg O o Cocood o O bocooo aE O Section A contains external connections to the holding cir cuit for manual reset applications The function and use of these connections varies somewhat depending on the cir cuit style of the instrument See steps 7 and 9 for details Caution Do not apply electrical current to terminals in Section A Section B contains the power connections for the control unit Standard unit is designed to operate on 24 VDC 24 VAC 50 60 HZ Caution Do not apply 120 240 VAC to the power connections Section C contains connections for SP1 and SP2 relays Connections are marked on the rear of the instrument 7 Setpoint Calibration Setpoint calibration is easily attained by actuating the pushbuttons located on the rear of the instrument Pushbuttons are labeled SP1 and SP2 To set the setpoint SP1 apply pressure where you
7. he clip firmly hold the case of the gage assembly be careful not to twist the electrical unit with one hand and rotate the front cover in the counter clockwise direction with the palm of the other hand The Mini Photohelic Switch Gage utilizes a bayonet locking design The cover will rotate approximately 9 degrees then stop and can be removed Caution When remov ing the cover be careful to slowly pull the cover straight off the gage housing Damage can occur to the scale if the cover is pulled off on an angle If difficult to loosen cover place a small sheet of rubber between the cover and the palm of the hand The zero adjust screw is located below the scale at the zero label near the base of the pointer Use the hex allen wrench supplied and adjust until the pointer is on zero This must be done with both pressure connections vented to atmosphere and the gage oriented in the final mounting position Replace cover 5 Pneumatic Connections To measure positive pres sure connect tubing to port marked and vent port to atmosphere For negative pressure vacuum connect to port marked and vent port to atmos phere If gage is supplied with 1 8 male NPT connec tions careful attention must be made not to over tighten fittings to avoid damage to the gage PANEL MOUNTED 6 Electrical Connections Refer to Fig C for electrical connections located on rear on Mini Photohelic Switch Ga
8. t Standard circuit style HH may be used to control various fans dampers pumps etc between the setpoints of a Mini Photohelic Switch Gage To accomplish this use one setpoint relay to reset the other as shown in the wiring diagram Fig F In this typical application the load would be connected to the N C contacts NC2 of the right set point relay SP2 The N O contacts of SP1 relay would be connected to the S2 reset terminals on the rear of the instrument On pressure rise to the right setpoint relay SP2 the relay would pull in and hold even though the pressure might fall below that setpoint If the pressure continued to fall to the left of setpoint SP1 then SP2 relay would be automatically DE ENERGIZED returning to its normal position and in so doing open the reset ter minal S2 The right setpoint relay SP2 would thus be reset and the cycle could repeat Copyright 2007 Dwyer Instruments Inc DWYER INSTRUMENTS INC P O BOX 373 MICHIGAN CITY INDIANA 46361 U S A Printed in U S A 2 07 Fig F SPI Wrep O 0 B s O OJ N s O Ol Hoste terol 5 o J LOAD O Ol O 12 Dual Setpoint Special Purpose Circuits Circuit Style LL may be used where manual reset following main tained contact on pressure decrease to either setpoint is required Circuit HL and LH are combination units For special combina
9. tions of features and special units con sult factory 13 Failure Mode The Mini Photohelic Switch Gage cir cuit design provides certain protection in the event of a loss of electrical power Both relays will de energize upon loss of power MAINTENANCE AND SERVICE The Mini Photohelic Switch Gages are precision instru ments expertly assembled and calibrated at the factory They require no lubrication or periodic servicing If the interi or is protected from dust dirt corrosive gases and fluids years of trouble free service may be expected Zero adjust ment should be checked and reset occasionally to maintain accuracy Upon final installation of the Series MP Mini Photohelic Differential Pressure Switch Gage and the companion receiver no routine maintenance is required A periodic check of the system calibration is recommended The Series MP is not field serviceable and should be returned if repair is needed field repair should not be attempted and may void warranty Be sure to include a brief description of the problem plus any relevant application notes Contact customer service to receive a return goods authorization number before shipping FR 14 443249 10 Rev 3 Phone 219 879 8000 Fax 219 872 9057 www dwyer inst com e mail info dwyer inst com
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