Frequency Output Depth and Pressure Transducers. Seismic Stuff Technology Pte. Ltd.

Transcription

1 Frequency Output Depth and Pressure Transducers Seismic Stuff Technology Pte. Ltd. Revision 1.12 Date 10 th August 2010

2 COPYRIGHT & DISCLAIMER NOTICE All information and material within this document are subject to copyrights owned by Seismic Stuff Technology Pte Ltd. (SST) and other individuals or entities. Any reproduction, retransmission, republication, or other use of all or part this document is expressly prohibited, unless prior written permission has been granted by SST, or the appropriate copyright owner. All other rights reserved. The names, logos and service marks of SST that appear in this document may not be used in any advertising, publicity, promotion, or in any other manner implying SST endorsement, sponsorship of, or affiliation with any product or service, without prior express written permission from SST. Although this document includes links to documents and/or Internet sites, SST takes no responsibility for the content or information contained on/in those other documents and Internet sites, nor does it exert any editorial or other control over the content contained within. In the preparation of the information contained on these pages, SST has endeavored to ensure that information is as accurate and current as possible. However, inadvertent errors can occur. Therefore, the information within this document is provided "as is," without any guarantee or warranty of any kind, express or implied. Copyright Seismic Stuff Technology Pte. Ltd. All rights reserved. Seismic Stuff Technology Pte. Ltd. 11 Changi North St. 1 #02-03 Changi North Industrial Estate Singapore Co.Reg R Tel. : Fax. : info@seismicstuff.com Website : Date: 10 th August 2010 Page 2 Revision 1.12

3 Introduction Seismic Stuff Technology's Frequency Output Depth Transducers are used to monitor the depth of the seismic source during operations. The Pressure Transducers are used to monitor the high pressure air supply to the source. By using miniaturization made possible with modern SMT electronics and the latest sensing technologies SST's transducers are less than half the size of traditional alternatives providing more options when mounting the device on the array. By using proprietary internal pressure filtering, the transducer is able to operate on shallow sources with close proximity to the individual guns without damaging the sensor. The transducers are connected via a two wire interface which allows the gun controller to supply power to the transducers. The transducer modulates the input current with a frequency proportional to the depth or pressure that the device is measuring. This modulated frequency is measured by the gun controller allowing it to recover the depth and pressure readings. Operation The transducers arrive factory calibrated and will function with all GCS90 compatible gun controllers. After connecting the device, a zeroing operation should be carried out on the gun controller with the transducer on deck at atmospheric pressure. Maintenance The transducers should provide years of reliable service but, depending on areas of operation, it may be necessary to service the internal filter assembly should it become blocked or clogged. Fig. 1 Internal Components Date: 10 th August 2010 Page 3 Revision 1.12

4 The internal components of the transducer are shown in Fig. 1 above. All models are similar and include the following components: - either: Machined AGP 2702F or Machined AGM 1704M Electronics Module Brass Compression Ring either: Low Pressure Transducer (DT) or High Pressure Transducer (PT) Possible configurations of the above parts: Depth Transducer Assembly with AGP2702F * Depth Transducer Assembly with AGM1704M * Pressure Transducer Assembly with AGP2702F * Pressure Transducer Assembly with AGM1704M * Also shown in Fig Transducer O-Ring (x2) * Machined Maze Filter Disc * Machined Blank Filter Disc * Face Seal O-Ring * * indicates replacement parts that can be ordered separately The procedure to disassemble the transducer for servicing is shown below: Remove the transducer from the array. Remove any fitting from the pressure sensing orifice. Clean the transducer and drain any water and deposits from the sensing orifice. Using a 36mm ring spanner for the connector and 36mm OE spanner on the flats on the main body, carefully loosen the connector 1 full turn. Using a wooden dowel or similar through the 1/4 NPT orifice push the internal components out of the main body while unscrewing the connector the remaining 2 ½ turns. Carefully set the transducer assembly to one side. Remove the two filter discs and compression o-ring from inside the main body. Carefully clean the filter discs, o-ring and the housing components with a soft toothbrush or similar and fresh water to remove any deposits. Date: 10 th August 2010 Page 4 Revision 1.12

5 Fig. 2 Stacked Components Prior to Assembly When the device is ready to be assembled, the components should be stacked as shown in Fig. 2 above. The order of the components from bottom to top is: - 1. Depth Transducer Assembly (connector, brass compression ring and transducer). The wires must be coiled loosely inside the brass compression ring so they are not pinched during the assembly process. 2. Machined Maze Filter Disc with the circular machined pattern facing upwards. This should be clean of any deposits, growth or deep scratches. This item can be cleaned with a soft bristled toothbrush if required. Spare discs can be ordered separately. 3. Machined Blank Filter Disc. This should be clean of any deposits, growth or deep scratches. This item can be cleaned with a soft bristled toothbrush if required. Spare discs can be ordered separately. 4. Face Seal O-Ring. This should be clean and undamaged. Spare O-Rings can be ordered separately. To prevent possible seizing of the connector threads inside the main housing, a very small amount of copper slip should be wiped onto the connector thread before assembly. Date: 10 th August 2010 Page 5 Revision 1.12

6 Fig. 3 Main Body Lowered Over Stacked Components Before assembly the housing of the transducer should be inspected for scratches or damage to the internal bore which could cause the o-rings to leak. Before assembly a small amount of silicone lubricant should be sprayed into the main body to allow the o-rings to slide smoothly during assembly. The body can then be lowered over the stacked components, as shown in Fig. 3, and pressed down in one motion without rotation until the body rests on the threads. The main body should then be rotated slowly anti-clockwise two full rotations before it is finally screwed clockwise to tighten to the connector to 289 ft/lb or 392 N/m. This two rotation anticlockwise action is required to minimize the amount of twisting in the wires between the electronics and the transducer. The assembled device should be checked after reassembly by connecting to the gun controller and applying known reference pressures to ensure the correct readings are given. Recalibration Each device is factory calibrated with the coefficients stored electronically within the device itself. Under most circumstances the device should provide years of reliable service. If it is determined that the transducer does require field recalibration please contact SST for further information. The procedure is reasonably straightforward and is conducted on the complete assembled transducers using a SST proprietary programming module available separately. Note: suitable reference pressures need to be available for this operation. Date: 10 th August 2010 Page 6 Revision 1.12

7 Specifications Ordering Information: Depth Transducer AGP2702F Pressure Transducer AGP2702F Depth Transducer AGM1704M Pressure Transducer AGM1704M Operational Performance: Depth Transducer Operating Range Scale Accuracy Pressure Transducer Operating Range Scale Accuracy 0 to 40 m 0.00 m 2000 Hz m 6000 Hz 1 Hz / cm of seawater +/- 0.1m (0-20m) 0 to 3000 PSI 0 PSI 2000 Hz 3000 PSI 5000 Hz 1 Hz / PSI +/ PSI ( PSI) Electrical Specification: Supply Voltage 15 to 35 Vdc Current 16 ma nominal Operating Temperature -20 ºC to +60 ºC External Connections: Electrical Connector or optionally Pressure Connector Pressure Filter AGP 2702F Pin 1 + Pin 2 - AGM 1704M Pin 1 + Pin 2 No Connection Pin 3 - Pin 4 No Connection 1/4 NPT Internal (field serviceable) Output: Pulse Width 26 µs Polarity Negative Physical Statistics: Length 118 mm (4 5/8 ) Diameter 44 mm (1 3/4 ) Weight 955 g (2 lbs) Material Stainless Steel 316 Date: 10 th August 2010 Page 7 Revision 1.12