Model Series 661 Amplifying Relays with Bias

Transcription

1 Siemens Energy & Automation INSTALLATION AND SERVICE INSTRUCTION INTRODUCTION Model Series 661 Amplifying Relays with Bias SD661 Rev 8 February 2006 Supersedes Rev 7 The Model 661 is a force-balance instrument that amplifies a pneumatic instrument signal. The output of the relay can be either direct or reverse acting, depending on the unit supplied (see Model Designation). The output is proportional to the input by the gain factor (e.g. 2:1, 1:2). Biasing is accomplished by setting the adjusting screw at the top of the instrument. This instruction has seven major sections: Introduction, Installation, Principle of Operation, Calibration, Maintenance, Warranty, and Parts List. Model Designation Model Series Amplification Gain Factor (Input-to-Output Ratio) Action 2-1:2, Model 661A2 2:1, Model 661R2R 3-1:3, Model 661A3 3:1, Model 661R3R R Reverse Action Blank Direct Action 661 A 2 R 4-1:4, Model 661A4 4:1, Model 661R4R 6-1:6, Model 661A6 6:1, Model 661A6R Specifications Supply Pressure Normal psig Minimum... 1 psig above maximum required output Maximum psig Range Limits Direct Acting psig output Reverse Acting psig input Overrange Limits psig to any connection Bias Range Direct Acting psi to + 30 psi Reverse Acting psi to psi Output Pressure, Minimum*... Less than 0.1 psig Ratio Accuracy*... Within 1% of nominal ratio Linearity*... ±1% of output span

2 Response Level* inh 2 O Reproducibility*... Within 0.1% of output span Flow Capacity, Minimum* SCFM Air Consumption, Maximum* SCFM Ambient Temperature Limits to +180 F (-40 to +82 C) 20 psig supply pressure INSTALLATION Shipping and Storage If the relay is to be stocked, stored, or shipped to another location prior to piping, make sure that the factory installed plastic plugs are in the ports to prevent entry of moisture, dirt, or other contaminants. Mounting The relay may be bracket or panel mounted. It can be panel mounted by removing the standard mounting bracket. A 25/32" diameter hole is required for panel mounting. Refer to Figure 1 for mounting dimensions. The relay may be mounted in any position, in any reasonably vibration-free location. Figure 1 Installation 2

3 PNEUMATIC CONNECTIONS Refer to Figures 1 and 2 for the pneumatic connections. All connections are 1/4" NPT except the reverse acting relay input which is 1/8" NPT. Recommended piping is 1/4" O.D. tubing, although any scale-free piping may be used. 1. Blow out all piping before connections are made to prevent the possibility of dirt or chips entering the relay. 2. Use pipe sealant sparingly, and then only on the male threads. A non-hardening sealant is strongly recommended. 3. Connect the relay to a source of clean, dry, oil-free relay air. See Instrument Air Requirements. CAUTION Exceeding the specified ambient temperature limits can adversely affect performance and may cause damage to the relay. Pressures in excess of those stated in the Specifications section may cause damage to the relay. Instrument Air Requirements Connect the instrument (i.e. relay) to a source of clean, dry, oil-free instrument air. Failure to do so will increase the possibility of a malfunction or a deviation from specified performance. CAUTION Use of process fluids other than instrument air is not recommended. No claim is made as to the suitability of this product for use with other process fluids, such as hazardous gases, except as listed on the appropriate certificate. Non-approved instruments are suitable for use with instrument air only. Optional features and modifications such as tapped exhaust do not imply suitability for use with hazardous gases except as listed on the approval certificate. There are many types of synthetic compressor lubricants. Some may not be compatible with the materials used in construction of the instrument. Wetting of these materials by such an oil mist or vapor, etc., may cause them to deteriorate. This may ultimately result in failure of the instrument. The following materials are in contact with the instrument air: Direct Acting Models: ALUMINUM, BRASS, CHROMED NICKEL PLATED BRASS, NICKEL PLATED BRASS, BUNA-N, CORPRENE, NEOPRENE, NYLON, HARDENED STEEL, and STAINLESS STEEL Reverse Acting Models: ALUMINUM, BRASS, NICKEL PLATED BRASS, FAIRPRENE, NEOPRENE, NYLON, HARDENED STEEL, and STAINLESS STEEL CAUTION Synthetic compressor lubricants in the air stream at the instrument may cause it to fail. The requirements for a quality instrument air supply can be found in the Instrument Society of America's "Quality Standard for Instrument Air" (ISA-S7.3). Basically, this standard calls for the following: Particle Size Maximum particle size in the air stream at the instrument should be no larger than 3 microns. Dew Point The dew point, at line pressure, should be at least 10 C (18 F) below the minimum temperature to which any part of the instrument air system is exposed at any season of the year. Under no circumstances should the dew point, at line pressure, exceed 2 C (35.6 F). Oil Content Maximum total oil or hydrocarbon content, exclusive of non-condensable, should not exceed 1 ppm under normal operating conditions. 3

4 PRINCIPLE OF OPERATION Refer to Figure 2 and Table 1 as needed while reading the following. DIRECT ACTING Input pressure force is exerted over the effective area of the top diaphragm and is balanced by the force of the output pressure exerted on the effective area of the lower diaphragm combined with the constant force of the lower spring. The amplifying ratio is fixed by the ratio of the input-to-output diaphragm areas. An increase in the input pressure will unbalance the opposing forces causing the diaphragm section to move downward. This downward movement closes the exhaust port and moves the pilot plunger off the supply port seat. Thus supply air is admitted, increasing the output pressure until a balance of forces is obtained. A decrease in the input pressure unbalances the diaphragm section upward, closing the supply port and opening the exhaust. Output pressure is exhausted until a balance of forces is obtained. Plus or minus biasing of the input signal, with an adjustment range equivalent to -15 to +30 psi, is accomplished by changing the setting of the upper biasing spring, which alters the net spring force on the diaphragm assembly. This setting is made by turning the slotted bias-adjustment screw at the top of the instrument. REVERSE ACTING Input pressure force is exerted under the top diaphragm which acts against the biasing spring. When the input pressure increases, an unbalance in opposing forces results and the diaphragm assembly moves up. This upward movement closes the supply port and opens the exhaust. The output pressure will exhaust until a balance of forces is obtained. A decrease of input pressure forces the diaphragm assembly down, closing the exhaust and opening the supply. Supply air is admitted, increasing the output pressure until a balance of forces is obtained. Positive biasing, with an adjustment range equivalent to 0 to psi, is accomplished by adjusting the slotted bias adjust screw at the top of the instrument. Table 1 Model vs. Gain and Functional Equations Direct Action Model No. 661A2 661A3 661A4 661A6 Functional Equation: P OUT = G (P IN ± K) Where: P IN = input pressure P OUT = output pressure G = gain Gain Reverse Action Model No. 661A2R 661A3R 661A4R 661A6R Functional Equation: P OUT = G (K - P IN ) K = bias (adjustable) Direct: -15 to +30 psi Reverse: to psi Gain

5 Figure 2 Schematics CALIBRATION The only internal adjustment is the adjustable exhaust seat which sets the input-output ratio. This is factory set for optimum performance. If the relay is rebuilt, or if the diaphragms are changed for a different ratio, the span may be set as follows: 1. Connect an air supply to the supply connection of the relay. 2. Connect an adjustable air supply with an accurate gauge into the input connection of the relay. 3. Connect the relay output to an accurate gauge. 4. With supply air on, exercise the relay by applying minimum to maximum input several times. Check for leaks in output piping. 5. Check the output span. If the span is too great, turn the exhaust seat clockwise. If the span is too small, turn the exhaust seat counterclockwise. NOTE The exhaust seat is accessible for adjustment by removing the retaining nut, valve spring, and valve plunger. Insert a 1/16" hex wrench through the bottom into the seat. Be careful when inserting the wrench to avoid damage to the seat. To set the proper bias, follow the first three steps above. Then, with supply air turned on, apply an input pressure within the operating range for which the unit is to be used. Turn the bias adjust screw until the output pressure increases or decreases to the desired bias pressure. 5

6 MAINTENANCE Most problems associated with pneumatic instruments can be prevented by providing clean, dry, oil-free instrument air (see Instrument Air Requirements). CAUTION Before disassembling the instrument, turn off supply air pressure to the instrument. Periodic opening of the blow-off valve in the filter dripwell will keep the regulated air supply free from dirt, oil, or other impurities. It will also prevent clogging of the plunger valve or the automatic bleed, in the relay. If the relay does not reduce the output pressure, it is evident that the plunger valve is not seating properly, due to dirt, or the automatic bleed may be clogged. 1. Remove the retaining nut on the bottom casting using care not to lose the valve plunger or spring which will drop out. 2. The pilot plunger must be clean on both seating surfaces. If necessary, use solvent to clean. 3. Clean the valve plunger seats using an ordinary smoking pipe cleaner and solvent. 4. Reassemble the pilot plunger, conical end toward the diaphragm and spring on the blunt end. 5. Replace and tighten retaining nut. If the relay does not increase the output pressure, the supply pressure may be too low. Excessive exhaust from the diaphragm ring during stable operation indicates a ruptured diaphragm or dirt on the pilot valve. The exhaust slots in the exhaust diaphragm must be kept open. If they become blocked, the relay must be disassembled. Product Support This section provides the Internet site address, address, telephone numbers, and related information for customers to access Siemens product support. When contacting Siemens for support: Please have complete product information at hand: For hardware, this information is provided on the product nameplate (part number or model number, serial number, and/or version). For most software, this information is given in the Help > About screen. If there is a problem with product operation: Is the problem intermittent or repeatable? What symptoms have been observed? What steps, configuration changes, loop modifications, etc. were performed before the problem occurred? What status messages, error messages, or LED indications are displayed? What troubleshooting steps have been performed? Is the installation environment (e.g. temperature, humidity) within the product s specified operating parameters? For software, does the PC meet or exceed the minimum requirements (e.g. processor, memory, operating system)? 6

7 A copy of the product Service Instruction, User s Manual or other technical literature should be at hand. The Siemens public Internet site (see the table) has current revisions of technical literature, in Portable Document Format, for downloading. To send an instrument to Siemens for repair, request a Return Material Authorization (RMA). SD661 IMPORTANT An instrument must be thoroughly cleaned (decontaminated) to remove any process materials, hazardous materials, or blood born pathogens prior to return for repair. Read and complete the Siemens RMA form(s). Contact Information United States of America Telephone , option 2 for Siemens and Moore brand instruments Fax PITechSupp@sea.siemens.com Hours of Operation 8 a.m. to 4:45 p.m. eastern time Monday Friday (except holidays) Public Internet Site Repair Service extension 3187 For contact information outside of the U.S.A., visit the Siemens public Internet site (see the above table for the URL), locate Customer Support Process Instrumentation, and click on the Contact Tech Support link to access the Global Support link. WARRANTY (a) Seller warrants that on the date of shipment the goods are of the kind and quality described herein and are free of non-conformities in workmanship and material. This warranty does not apply to goods delivered by Seller but manufactured by others. (b) Buyer's exclusive remedy for a nonconformity in any item of the goods shall be the repair or the replacement (at Seller's option) of the item and any affected part of the goods. Seller s obligation to repair or replace shall be in effect for a period of one (1) year from initial operation of the goods but not more than eighteen (18) months from Seller s shipment of the goods, provided Buyer has sent written notice within that period of time to Seller that the goods do not conform to the above warranty. Repaired and replacement parts shall be warranted for the remainder of the original period of notification set forth above, but in no event less than 12 months from repair or replacement. At its expense, Buyer shall remove and ship to Seller any such nonconforming items and shall reinstall the repaired or replaced parts. Buyer shall grant Seller access to the goods at all reasonable times in order for Seller to determine any nonconformity in the goods. Seller shall have the right of disposal of items replaced by it. If Seller is unable or unwilling to repair or replace, or if repair or replacement does not remedy the nonconformity, Seller and Buyer shall negotiate an equitable adjustment in the contract price, which may include a full refund of the contract price for the nonconforming goods. (c) SELLER HEREBY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, EXCEPT THAT OF TITLE. SPECIFICALLY, IT DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, COURSE OF DEALING AND USAGE OF TRADE. 7

8 (d) Buyer and successors of Buyer are limited to the remedies specified in this article and shall have no others for a nonconformity in the goods. Buyer agrees that these remedies provide Buyer and its successors with a minimum adequate remedy and are their exclusive remedies, whether Buyer's or its successors remedies are based on contract, warranty, tort (including negligence), strict liability, indemnity, or any other legal theory, and whether arising out of warranties, representations, instructions, installations, or nonconformities from any cause. (e) Note: The above does not apply to any software which may be furnished by Seller. In such cases, the attached Software License Addendum applies. All product designations may be trademarks or product names of Siemens Energy & Automation, Inc. or other supplier companies whose use by third parties for their own purposes could violate the rights of the owners. Siemens Energy & Automation, Inc. assumes no liability for errors or omissions in this document or for the application and use of information in this document. The information herein is subject to change without notice. Procedures in this document have been reviewed for compliance with applicable approval agency requirements and are considered sound practice. Neither Siemens Energy & Automation, Inc. nor these agencies are responsible for repairs made by the user. 8

9 PARTS LIST Siemens Model Series 661A Direct Acting Amplifying Relays with (±) Bias SD661 Drawing 14412PL Rev 9/81 IMPORTANT Service Parts Kits are available for servicing the instrument. Contact Siemens for available kits; refer to the Product Support section of this instruction. Some parts in this Parts List may not be available for separate purchase. 9

10 PARTS LIST Siemens Model Series 661A_R Reverse Acting Amplifying Relays with (+) Bias Drawing 14495PL Rev 9/81 IMPORTANT Service Parts Kits are available for servicing the instrument. Contact Siemens for available kits; refer to the Product Support section of this instruction. Some parts in this Parts List may not be available for separate purchase. 10