How to Read a Telemetry Signal With O-scope

TRANSDUCERS AND Data ACQUISITION

RICHARD HATHAWAY , KAH WAH LONG , in Fatigue Testing and Assay, 2005

one.xiv.2 TELEMETRY SYSTEMS

Telemetry systems are an alternative method of transmitting data from the rotating associates to the stationary data acquisition arrangement. Basic telemetry systems consist of a modulator, a voltage-controlled oscillator (VCO), and a power supply for the strain gage bridge. The indicate from the strain gage bridge is used to pulse attune a abiding-amplitude square wave. The output pulse width is proportional to the voltage from the bridge. This foursquare moving ridge serves to vary the frequency of the voltage-controlled oscillator, which has a eye frequency ( f _c). The VCO signal is transmitted by an antenna mounted on the rotating shaft and is received past a stationary loop antenna, which encircles the shaft. Later the signal is received, it is demodulated, filtered, and amplified before recording. Near of the transmitting unit of measurement of a telemetry SYSTEM is completely self-contained. The power supply to the components on the rotating shaft is obtained by inductively coupling the power supply through the stationary loop antenna. Effigy 1.54 is a schematic diagram of the operating principle of a typical single channel telemetry arrangement.

Figure 1.54. Schematic diagram of a simplified telemetry arrangement.

When more than one channel is to be transmitted, two different methods can exist used: frequency-partition multiplexing and time-division multiplexing. In addition to more VCOs, the frequency-segmentation multiplexing uses multiplexing equipment to adhere specific channel data to specific frequencies before transmitting. The VCO is designed and so that the VCO output frequency range of each channel is not overlapped. At the receiving cease, demultiplexing equipment is required to carve up the frequencies and then that the data in each channel are restored.

In fourth dimension-division multiplexing, all the channels utilise the same frequency spectrum, merely at unlike times. Each aqueduct is sampled in a repeated sequence by a commuter edifice a composite point containing the time-spaced signals from each aqueduct. A decommuter, operating at the aforementioned frequency as that of the driver, separates the channels at the receiving end. Because the channels are not monitored continuously, the sample rate must be sufficient to ensure that the signal amplitude does not alter appreciably during the time between samples. Most telemetry systems employ sample rates at to the lowest degree five times higher than the highest expected frequency.

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Analog forepart-cease and telemetry systems

Darrin J. Young , in Implantable Biomedical Microsystems, 2015

iii.5 Telemetry System Introduction

Telemetry system is a critical part of a bioimplantable systems design. The organisation not just needs to receive external command to control the operation of an implant but besides receives external power to energize an implant in a bombardment-less manner or to recharge an implanted battery. Diverse techniques based on RF and ultrasound take been demonstrated. The RF approach tin can couple an appreciable amount of power to an implanted antenna positioned relatively shut to the peel surface, while the ultrasound ways tin transfer power deeper into the tissue merely deserves a conscientious consideration of impedance matching betwixt an ultrasound transceiver and the surrounding tissue. In this chapter, the RF approach will be chosen equally the focus for word. Due to implant size and weight constraints, the telemetry system needs to be highly miniaturized, thus presenting a pattern challenge for achieving an efficient operation. Too receiving external control and ability, the organisation is also responsible for wirelessly transmitting data to an external receiver. Various design requirements, for example, manual distance, data rate, and ability dissipation, phone call for an optimized design in terms of telemetry topology and implementation trade-offs.

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Collection OF Data

D.J. HARRIS , ... D. NUTTALL , in Coal, Gas and Electricity, 1980

3.three.two Periodicity of Meter Readings

Although telemetry systems enable the gas taken past some big industrial consumers to exist recorded daily, most meters are read quarterly over a cycle. This ways that the precise amount of gas used by consumers in a given calendar period is subject to estimate since the meter registrations would ordinarily include consumption from a previous menstruation. The Institution of Gas Engineers published a method of dealing with the calculation of gas quantities as part of an investigation into unaccounted for gas which began in 1938 [ B 88]. In recent years the British Gas Corporation has instituted a standard method for estimating unread gas which has regard to:

(a)

the consumption levels of individual consumers;

(b)

the number of days for which an estimate is required for each consumer;

(c)

an observed human relationship between temperature and gas consumption levels obtained from a linear regression.

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Volume 3

Sarah Audet , ... Glen Vaughn , in Comprehensive Microsystems, 2008

3.14.two.iv Communication Technologies for Medical Applications

Wireless biomedical telemetry is used in hospitals, clinics, homes, ambulances, and other healthcare institutions. This telemetry is typically function of an external biomedical monitoring and diagnostic arrangement, a torso-worn device, or an implantable medical device designed to get together information, administer therapy, and perhaps provide therapy adjustment for the patient. These devices exchange data with a system designed for medical professional apply, or with the patient. Typically, biomedical telemetry is administered, or prescribed for use by a healthcare professional.

Originally the term wireless telemetry was divers as the transmission and measurement of data from remote sources by radio. This definition has expanded to include telecommand that involves the control/reprogramming of devices, and additionally, has expanded across radio to include infrared and ultrasonic communications.

Electric current wireless biomedical telemetry systems can be very sophisticated, are primarily radio-based, and can exist divided into the following three general classes of devices:

•

Healthcare facility-based wireless (i.e., EKG and pulse oximetry transmitters that allow a patient'southward mobility well-nigh most of one hospital floor while being continuously monitored).

•

Implanted and body-worn telemetry systems that are function of portable therapeutic and monitoring systems can be controlled and read past both healthcare professionals with physician-programming devices and past patients with handheld devices. These can exist used both in wellness care facilities and in dwelling house use environments.

•

Personal health assistant devices. These can be blood glucose monitors, pulse rate, claret pressure level monitors, or weight scales. These tin be nonprescribed consumer electronics. Use of these types of devices in healthcare management systems is condign more than prevalent.

Wired biomedical telemetry systems, typically hospital-based and connected to the hospital computer network, are quite common. While non covered hither, it is worth noting that these systems can automatically measure out claret force per unit area, heart charge per unit, arterial oxygen saturation levels, respiration rate, and permit manual data input for managing hospitalized patients. Wireless systems permit patient mobility to the bathroom, exercise, and allow for general patient example of mobility and comfort. They can also provide increased patient safe due to the continuous monitoring attribute of wireless telemetry.

Wireless biomedical telemetry systems are regulated by both the U.s. Federal Communications Committee (FCC) and the FDA. The FCC defines the RFs allowed for use in transmitting biomedical data, and the power levels allowed. The FDA defines electromagnetic interference (EMI) immunity and safety requirements of therapeutic devices and the associated telemetry interaction at the system level. The frequencies and power levels are important parameters when designing a biomedical telemetry arrangement. The number of users and their power levels, along with human-made noise, can cause significant interference to certain frequency bands. This is ane reason why the FCC has created protected frequency bands specifically for biomedical telemetry. These include the wireless medical telemetry system (WMTS) for in-hospital utilise and the medical implant communications service (MICS) for implantable use. Nonlife disquisitional telemetry ofttimes uses the nonprotected industrial, scientific and medical (ISM) bands. The medical portion of the ISM ring is related to radio diathermy and other noncommunications utilise of RF. At that place are many industrial, commercial, scientific, and home uses of the ISM band, which tin can lead to meaning noise and interference levels on the bands (i.due east., cordless phones, WiFi, Bluetooth).

Hospital-based wireless EKG telemetry systems are ubiquitous. Currently manufactured systems employ the WMTS frequency band. The post-obit paragraph is an excerpt from the FCC WMTS website that describes the creation of this frequency ring quite well:

Prior to the establishment of the WMTS, medical telemetry devices generally could be operated on an unlicensed basis on vacant television set channels 7–13 (174–216   MHz) and xiv–46 (470–668   MHz) or on a licensed but secondary footing to private land mobile radio operations in the 450- to 470-MHz frequency band. This meant that wireless medical telemetry operations had to take interference from the primary users of these frequency bands, i.e., the television broadcasters and private country mobile radio licensees. Further, if a wireless medical telemetry operation caused interference to television or private state mobile radio transmissions, the user of the wireless medical telemetry equipment would exist responsible for rectifying the problem, even if that meant shutting down the medical telemetry operation.

The FCC was concerned that certain regulatory developments, including the advent of digital television (DTV) service, would result in more intensive utilize of these frequencies by the primary services, subjecting wireless medical telemetry operations to greater interference than before and perhaps precluding such operations entirely in many instances. To ensure that wireless medical telemetry devices tin operate free of harmful interference, the FCC decided to establish the WMTS, in a Report and Club released on June 12, 2000 (FCC 2006).

The impetus for alter occurred in mid-2000, following an incident at Baylor Academy Medical Heart where a HDTV broadcast interrupted medical telemetry in part of the hospital for a brusk time (Baker 2002). This incident led to WMTS being created by the FCC, and older systems being phased out via attrition. Frequency assignment to channels in the WMTS band are all the same handled past a frequency coordinator to ensure that multiple uses of the frequency band within the hospital do not interfere with each other.

On the implantable side of wireless biomedical telemetry óne of the earliest uses of implantable telemetry involved the control of the pacing rate of implantable cardiac pacemakers. Originally, the control of the outset pacemakers involved piercing the pare of the patient with a custom-sharpened screwdriver to accommodate a pocket-size potentiometer encased in a waterproof silicone condom seal. Much to the patients' please, a simple inductively coupled 160–190-kHz two-style telemetry system replaced the screwdriver and allowed painless aligning of the pacemaker'southward pacing rate. This telemetry organization, which operates over a short range of just a few inches, was originally used by Medtronic Inc., starting time in the 1960s. Many medical implant manufacturers are still using these curt-range inductively coupled systems.

Implantable telemetry systems currently in use today are evolving into longer-range telemetry, which includes the use of the MICS band from 402 to 405   MHz (nearly worldwide allotment), the 902–928-MHz ISM bands in the Us, and the 433 and 868   MHz bands in Europe.

The MICS ring is an ultra-low-power band designed to be shared between conditions balloons (Meteorological Aids) and medical implantable devices. This ring provides licensing by rule, and protection confronting interference from nonlicensed interferers. The ISM bands allow the use of higher ability levels, but must share the use of the frequency bands with other devices operating with much more than efficient antennas and much college power than implanted battery-operated systems. Due to body losses and express battery power, implanted transmitters are typically the weakest link in the telemetry link and require a tranquillity, protected frequency band to operate consistently and effectively. The FCC created MICS to provide this.

For external to external and body-worn to external medical telemetry communications that are intended to operate outside healthcare facilities, the options are more than limited. Primarily FCC Part 15 and the ISM bands provide the frequency solutions. Using these frequency bands is complicated by the different international radio regulations that have different frequencies and ability levels between the United States and Europe. This makes a mutual worldwide solution very difficult. Unlike products often need to be designed for dissimilar countries.

The future of wireless biomedical telemetry will require systems that operate on common worldwide frequency bands to accommodate travelers. Ameliorate use of frequency spectrum and abstention of interferers volition also be necessary every bit wireless devices proliferate. Clear channel access protocol, and mind-earlier-talk protocols forth with cognitive radio concepts and automatic frequency agility tin be utilized to mitigate interference and channel-loading concerns.

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A Case Study of Reuse and Conservation of Water during Resource Management

Joel Kimmelshue , in Sustainable Land Evolution and Restoration, 2010

18.7.one Overview of Telemetry System

An automated remote telemetry system volition be used to measure, store, and transmit sampling data. The components of the system are as follows:

1.

Water flow for treated RCM water is measured at the water treatment facility (WTF) and pumping station.

2.

Treated RCM water quality (temperature, TDS, pH) is measured via sondes at the WTF and pumping station, and downstream of the pumping station.

3.

CAP water quality data is obtained from a water quality sensor (sonde) upstream of the pumping station.

four.

H2o quality sondes send data to a data logger for storage.

5.

The data logger sends data (via cellular modem) to the information-housing software at RCM for data management.

6.

The NMIDD enters a daily water order (CAP quantity) into data-housing software.

seven.

The data-housing software evaluates water quality (RCM and CAP) and quantity data (CAP) to automatically calculate the book of treated RCM h2o needed to fulfill the NMIDD need.

8.

The data-housing software sends an eastward-mail alarm to the WTF operator and pertinent project cooperators and then WTF pumps can be adjusted, if needed.

9.

Field sampling staff enter manual sampling information (soil, tissue, water) into the data-housing software.

10.

The data-housing software sends information to the Web Information Eye Spider web site for project cooperator and grower access.

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Sensor Theory

Robert D. Christ , Robert L. WernliSr., in The ROV Manual (2nd Edition), 2014

12.1.6 Systems

A sensor system comprises all aspects of the sensor from the initial sensing unit to the ultimate capture and disposition of the information (Figure 12.13). In Affiliate 13, the transmission protocols volition be discussed in more depth. For this department, a simple description is in order.

Figure 12.xiii. Simplified model of a sensor organization.

For sensor transmission, the data tin either be channeled through the vehicle's telemetry system as a advice channel or information technology may be completely separated into its own transmission conduit. A typical manufacture standard ROV telemetry system will have equally standard equipment a number of serial communication channels. Equally an case, a common mid-sized cobweb-based ROV system (in this instance, a Sub-Atlantic Mohican) has the post-obit data channels provided through the telemetry system:

•

3×RS-232

•

1×RS-485

•

1×Unmarried Mode Cobweb

A typical ROV umbilical–tether system combination volition provide one or more fibers along with spares encased inside a metal or plastic tube embedded in the umbilical/tether. As an culling to use of the vehicle'due south telemetry system (due, perhaps, to the sensor data requirement exceeding the capacity of the vehicle's telemetry aqueduct), one of the spare fibers can exist cleaved out from the cobweb bundle for routing to the sensor parcel. The benefit is a clean and articulate line for the sensor. The cost is the requirement for a fiber-optic multiplexer on both the vehicle and the surface for transmit and receive (TX/RX) functions on the spare fiber as well as the requirement for another pass on the fiber-optic rotary joint (FORJ or "slip ring").

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Wireless information communication for ECoG implants

Sohmyung Ha , ... Gert Cauwenberghs , in High-Density Integrated Electrocortical Neural Interfaces, 2019

7.four System implementation

For the experimental validation a prototype Cook modulation IC and board-level telemetry system were implemented as shown in Fig. 7.vii. The IC integrates a full-wave rectifier, clock recovery comparator, phase-locked loop (PLL), bias blocks, switch for data modulation, and auxiliary circuitry for data manual and organization control, equally highlighted in the dashed box in Fig. seven.7. Outside the IC, the secondary side includes a parallel LC tank ( ${\mathrm{50}}_2$ and $C_2$ ), a load capacitor $C_L$ , and a load resistor $R_L$ for modeling load current. On the primary side, a series LC tank ( ${\mathrm{50}}_1$ and $C_1$ ) is located concentric to the parallel LC tank of the secondary side for ability and data transfer. Measured geometries and parameters of the principal and secondary coils are equally follows: $L_1=5.27\mu$ H, $R_1=\mathrm{v.92}\mathrm{\Omega }$ , $Q_1=75.85$ , $D_1=\mathrm{vi.5}$ cm, $N_1=6$ , ${\mathrm{50}}_2=2.47\mu$ H, $R_{\mathrm{ii}}=\mathrm{two.79}\mathrm{\Omega }$ , $Q_2=75.43$ , $D_2=\mathrm{four.ii}$ cm, and ${\mathrm{Northward}}_2=8$ where $L_{1,2}$ represent the inductances, $R_{1,\mathrm{two}}$ the parasitic resistances, $Q_{1,2}$ the quality factors, $D_{\mathrm{i},\mathrm{ii}}$ the diameters, and $N_{\mathrm{ane},\mathrm{ii}}$ the numbers of windings for the primary and secondary coils, respectively, for each link. Values of the external surface-mount device (SMD) chip capacitors ( $C_1$ and $C_{\mathrm{two}}$ ) were called for 13.56-MHz resonance on both sides. For precise control of distance betwixt the coils, plastic spacers of calibrated lengths were inserted in-between. Data bit streams were generated in field-programmable gate-array (FPGA) on the secondary-side lath, and were fed to the telemetry IC capturing the information bit stream and producing the data pulse (Information) to drive the modulation switch beyond the coil accordingly. On the primary side, a signal generator generated a 13.56-MHz sine moving ridge input to the primary LC tank. The voltage $V_{\mathrm{Fifty}1}$ beyond the primary coil was sampled with an oscilloscope and decoded in Matlab to determine bit error rates.

Figure 7.7. Block diagram of the implemented system for power and data telemetry.

Detailed excursion diagrams of major system blocks are depicted in Figs. 7.eight and 7.10. As shown on the left side in Fig. 7.8(A), the mutual-gate comparator detects the timing when the voltage beyond the tank is zero for generation of synchronized single-cycle shortings by comparison the ii tank voltages $V_{\text{LL}}$ and $5_{\text{RR}}$ . While comparators in conventional rectifiers compare curl voltages with ${\mathrm{Five}}_{\text{DD}}$ to directly generate switch signals for rectification, the comparator in this work is used for clock recovery as reference to a PLL generating the switching signals instead, lowering the comparator power consumption and blueprint complexity.

Figure 7.8. Circuit diagrams of (A) the comparator, PLL and pulse and clock generation blocks and (B) voltage-controlled oscillator (VCO).

The recovered clock from the comparator ${\mathrm{Five}}_{\text{REF}}$ is fed equally the reference clock to the 22-phase frequency-doubling type-2 PLL shown in Fig. 7.viii(A). Its voltage-controlled oscillator (VCO) consists of xi filibuster cell stages as depicted in Fig. 7.8(B). Currents to the delay cells are controlled through both pMOS and nMOS electric current sources for balancing the voltage range of the delay cell outputs. For differential performance, cross-coupled nMOS differential pairs are inserted across the differential outputs in each cell.

The PLL directly controls the timing of the data pulse (Data) shorting the LC tank for data transmission. Hence PLL timing accuracy is critically important for maintaining low BER and high energy efficiency in data transmission. At the same time, the power consumption of the PLL should exist contained to minimize the total ability for overall free energy efficiency. Simulations of the trade-off between LC tank power loss and VCO ability consumption as a function of RMS VCO jitter in Fig. seven.9 demonstrate minimal bear upon on information transmission efficacy and overall energy efficiency for VCO jitter less than 1 ns. The measured jitter of 440 ps (Fig. seven.15(B)) is about the optimal trade-off bespeak in Fig. 7.9.

Figure seven.ix. LC tank ability loss and VCO power consumption every bit a function of the PLL RMS menstruation jitter. The LC link was simulated in Cadence to obtain power loss of the secondary LC tank by varying the jitter. The PLL jitter was imitation using a behavioral simulator (CppSim [56]).

The PLL and the rectifier pulse generator produce the phase-tuned pulses $P_{\text{INL}}$ and $P_{\text{INR}}$ gating the pMOS switches of the total-wave rectifier shown in Fig. 7.10(A). During data transmission, the clocks to the PLL phase-frequency detector (PFD) are blocked by a mask signal not to disturb the PLL locking.

Effigy 7.10. Circuit diagrams of (A) full-wave rectifier with data modulation switch across the LC tank, and (B) information chip synchronization and PLL/rectifier mask generation timing circuits.

Equally illustrated in Fig. 7.11, the 22 phases of the VCO are aligned over each half-cycle of the resonant tank. Amidst the 22 phases, ane is selected to generate $P_{\text{INL}}$ and $P_{\text{INR}}$ for total-moving ridge rectification, alternating betwixt $5_{\text{LL}}$ -active and $V_{\text{RR}}$ -agile one-half-cycles. Hence, whatsoever delay in the clock recovery due to the comparator can be compensated by selecting a shifted stage signal in the PLL feedback $V_{\text{FD}\mathrm{\_}\mathrm{two}\times }$ to align the PFD feedback $5_{\text{FD}}$ to the delayed recovered clock $V_{\text{REF}}$ . As a event, design requirements on comparator delay tin be relaxed to minimize power consumption.

Effigy 7.eleven. Timing diagram of the multiple phases of the PLL aligning with the LC tank signals Five _LL and 5 _RR, the switching signals for rectifier P _INL and P _INR, and the PLL input and feedback signals V _REF, V _{FD_2×} and V _FD. Comparing filibuster of the clock recovery comparator shown in 5 _REF is compensated by feeding a delayed stage back to the PLL look.

The schematic of the total-wave rectifier with two cantankerous coupled nMOS transistors and 2 pMOS switches driven by buffered phase pulses $P_{\text{INL}}$ and $P_{\text{INR}}$ is shown in Fig. 7.10(A). An additional nMOS switch beyond $V_{\text{LL}}$ and $5_{\text{RR}}$ is provided for Melt synchronous shorting by the buffered Information signal during data manual. While the body terminals of the nMOS transistors connect to the grounded substrate, the body terminals of the pMOS transistors share an north-well connected to a three-fashion dynamic body bias generator shown in the inset of Fig. 7.x(A). The dynamic body bias generator tracks the highest voltage amid the iii source/drain voltages: ${\mathrm{Five}}_{\text{LL}}$ , $V_{\text{RR}}$ , and $5_{\text{DD}}$ .

Equally shown in Fig. 7.10(B), the data fleck synchronization excursion receives external data $.25 (DIN) to generate the shorting signal (DATA), which drives the switch across the LC tank. As depicted in Fig. 7.12, this circuit synchronizes the data indicate with $F_{TXI}$ , generated from the PLL and transmitter clock generator as shown in Fig. seven.eight(A).

Figure 7.12. Timing diagram of data fleck reception and synchronization (DIN and Data), and mask signal generation for stable PLL and rectifier functioning. By masking V _REF and 5 _FD during data bit transmission, clock edge misalignment and edge missing issues are resolved in the masked signals $5_{\text{REF}\mathrm{\_}\text{M}}$ and $V_{\text{FD}\mathrm{\_}\text{M}}$ .

Shorting of the LC tank signals ( $V_{\text{LL}}$ and $V_{\text{RR}}$ ) for data manual may atomic number 82 to missed clock recovery, the disturbance of the PLL loop, and current leakage in the rectifier. These potential problems are avoided in this design by generating a mask signal MASK in the excursion shown on the bottom of Fig. 7.10(B). As shown in Fig. seven.12, the recovered clock from the comparator serving as the PLL reference clock $V_{\text{REF}}$ rises too early during the short, and misses the next rising edge afterward the short. Past applying the MASK point, ${\mathrm{Five}}_{\text{REF}\mathrm{\_}\text{M}}$ and $V_{\text{FD}\mathrm{\_}\text{K}}$ are free of imitation and missing clock edges into the PLL. Similarly, the mask signal is as well applied to the rectifier to preclude any opposite current leakage during the shorts.

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Mobile and Stationary Damage Monitoring

Thomas Merkle M. Eng. Dipl.-Ing. (FH) , in Damages on Pumps and Systems, 2014

Telemetric Transmission

As already mentioned above, the readings can be transferred wireless with the help of a telemetry system. The sensors deliver coordinating readings to the fastened transmitting station, which is mounted near the pump. Earlier the telemetric transmission occurs, the analogous measuring signals are digitized and transferred in the MHz tape (megahertz) to the receiver. The telemetry receiver station is located at the measuring PC or at the PC-control station. The transferred digital readings are at first converted for the further processing and so written into a file or deposited in an allocated RAM retention. [12]

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Pipe-in-pipe and Package Systems

Yong Bai , Qiang Bai , in Subsea Pipelines and Risers, 2005

Launch

Upon completion of fabrication and testing, the bundle will be outfitted for tow and installation with ballast concatenation, telemetry system and other installation aids. Breakout and pull forces during various stages of the launch shall exist calculated and assessed for the bundle system.

Pre-tow preparation

The pre-tow preparation volition commence with the activities including towhead inspection, trimming, bundle submerged weight check and tow training.

Tow to field

The bundle system will exist towed to the field by use of CDTM forth a pre-surveyed route. During tow, the drag on the anchor chain creates a 'lift force", so reduces the bundle submerged weight. This elevator force will result in a complete lift off from the seabed into CDTM mode. When the two arrives virtually the field, the parcel will be lowered to the seabed in the designated parking surface area situated in front of the bundle installation area.

Infield installation

The infield installation of the package system will exist carried out by remote intervention, which will be carried out directly by ROV.

The bundle will be towed at a irksome speed in off-lesser way into the installation area. After calculation weight to the bundle, the off-bottom tow can embark. During the off-bottom tow the bundle position must exist monitored at all times.

The packet will be pulled in at a straight line. A temporary target box will be determined for the leading towhead.

When the towheads and packet position have been confirmed, flooding down of the bundle can embark.

CDTM involves the transportation of prefabricated and fully tested flowlines, command lines and umbilicals in a bundle configuration suspended between two tugs. A further vessel accompanies the tow as a patrol/survey vessel. To maintain control during tow, the bundle is designed and constructed within specified tolerances with respect to its submerged weight.

The package is designed to have buoyancy, this being achieved by encasing the bundled pipelines, command lines, umbilicals etc. within a carrier piping. Anchor bondage are attached to the carrier piping at regular intervals forth its length to overcome the buoyancy and provide the desired submerged weight.

The tow speed has a directly elevator and straightening effect on the bundle. By controlling the tow speed in combination with the tension exerted by the tugs the packet tow characteristics and deflections are maintained.

The tow is controlled by adjustment of the tow wire length, tow wire tension, tow speed and the tug's relative positions. In this manner the tow depth, ambit shape, stresses and movement are kept inside specified operational limits under given ecology weather condition.

During tow the bundle is kept well clear of the seabed to enable a safe and unobstructed passage. The towheads are kept beneath the surface to minimize the effect of surface waves. The towhead depth is commonly about 30m below the surface but this controlled depth can exist increased or reduced by adjustment of the tow wire lengths.

On arrival in the field the bundle is gradually lowered past aligning of the controlling parameters (tow wire length, frontwards speed and tension) and the package settles in a position of equilibrium above the seabed with the lower portion of the chains resting on the seabed. Once in this position the bundle can easily be maneuvered in the off-lesser mode to its concluding position and the towheads located in the required target areas. The carrier annulus is flooded with inhibited seawater and the bundle settles on the seabed.

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Piping-in-Pipe and Package Systems

Qiang Bai , Yong Bai , in Subsea Pipeline Design, Assay, and Installation, 2014

Package Installation by CDTM

The most feasible and reliable way of bundle installation is past use of controlled-depth tow method, which is a subsea pipeline installation arrangement.

The principle of the CDTM involves the transportation of the packet towed between two lead tugs and i trail tug. By decision-making the tow speed in combination with the tension maintained past the abaft tug and the trailing towhead, the package configuration and its deflections are kept nether command during the tow. The essential parameters are continuously monitored during the tow and adjusting if necessary to maintain the desired bundle configuration well articulate of the seabed; its nominal position during tow is some 30 m below bounding main surface.

The complete installation of bundle organisation includes the following main activities.

Launch

On completion of fabrication and testing, the bundle is outfitted for tow and installation with a anchor chain, telemetry systems, and other installation aids. Breakout and pull forces during diverse stages of the launch should be calculated and assessed for the package organization.

Pretow Preparation

The pretow preparation commences with the activities including towhead inspection, trimming, parcel submerged weight check, and tow training.

Tow to Field

The parcel system is towed to the field by use of CDTM along a presurveyed route. During towing, the drag on the ballast chain creates a "lift forcefulness", and so reduces the packet submerged weight. This lift strength results in a consummate lift off from the seabed into CDTM mode. When the tow arrives about the field, the bundle is lowered to the seabed in the designated parking area, situated in front of the bundle installation area.

In-Field Installation

The in-field installation of the bundle system is carried out by remote intervention, which is carried out directly by ROV (remotely operated vehicles). The package is towed at a boring speed in off-bottom mode into the installation area. After calculation weight to the bundle, the off-bottom tow can commence. During the off-bottom tow, the bundle position must be monitored at all times. The packet is pulled in at a straight line. A temporary target box is determined for the leading towhead. When the towheads and parcel position have been confirmed, flooding down of the bundle can embark.

CDTM involves the transportation of prefabricated and fully tested flowlines, command lines, and umbilicals in a bundle configuration suspended between ii tugs. A further vessel accompanies the tow as a patrol or survey vessel. To maintain control during towing, the bundle is designed and constructed within specified tolerances with respect to its submerged weight.

The bundle is designed to have buoyancy, this existence achieved by encasing the bundled pipelines, control lines, umbilicals, and so forth inside a carrier pipe. Ballast bondage are attached to the carrier pipe at regular intervals along its length to overcome the buoyancy and provide the desired submerged weight, as shown in Figure 17.11. The carrier pipe is sized and then that the bundle is slightly positively buoyant, then chains are attached to the underside. The bundle is next towed out into a sheltered bay. Being positively buoyant, the carrier pipe rises from the seabed and lifts the chain until enough links are suspended to annul buoyancy. Chains can be easily cutting by ROV to trim bundle for tow, if required.

Figure 17.xi. Control depth tow method.

Source: Watson and Walker [three].

The tow speed has a direct lift and straightening effect on the bundle. By controlling the tow speed in combination with the tension exerted past the tugs, the bundle tow characteristics and deflections are maintained.

The tow is controlled by adjustment of the tow wire length, tow wire tension, tow speed, and the tug'south relative positions. In this fashion, the tow depth, ambit shape, stresses, and motility are kept within specified operational limits under given ecology conditions. During towing, the parcel is kept well clear of the seabed to enable a safe and unobstructed passage. The towheads are kept below the surface to minimize the result of surface waves. The towhead depth is usually about thirty chiliad below the surface, but this controlled depth can exist increased or reduced by adjustment of the tow wire lengths.

On arrival in the field, the bundle is gradually lowered past aligning of the decision-making parameters (tow wire length, forward speed, and tension), and the packet settles in a position of equilibrium above the seabed with the lower portion of the chains resting on the seabed. In one case in this position the bundle can easily be maneuvered in the off-bottom mode to its final position and the towheads located in the required target areas. The carrier annulus is flooded with inhibited seawater, and the bundle settles on the seabed.

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https://world wide web.sciencedirect.com/science/article/pii/B9780123868886000171

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Source: https://www.sciencedirect.com/topics/engineering/telemetry-system

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