Monitoring transmitter units

A factor which previously limited installation of automatic corrosion monitoring systems was the cost of cabling between sensors and control room instrumentation-this was particularly relevant to the electrical resistance (ER) systems. Developments to overcome this have included transmitter units at the probe location providing the standard 4-20 mA output (allowing use of standard cable) for onward transmission to data systems or the use of radio linkage which has been successfully used for other process-plant instrumentation. 

A complete range of instrumentation is available from portable units to automatic systems utilising many probes. Transmitter units are available which can be located at the probe and transmit ER data into the 4-20 mA standard instrument signal. Radio linkage from transmitter to control room or nearby offshore platform is available commercially. A satellite link has been used to monitor offshore platform ER probes at the onshore base in a Norwegian oilfield. 

Computers dedicated to corrosion monitoring may be used to receive data from corrosion probes, either via transmitter units or multiplexers. The computer facilities enable selection of recording... 

To obtain the benefits of this seal, it is necessary to install a gauge indicating the actual seal chamber pressure. Sensors and transmitters can be used to monitor and act on a pressure change. One of the two seals can fail without product loss or fugitive emissions. This seal would be connected to a pumping unit seen later in this chapter. 

In an effort to reduce the noise problems often encountered during in vivo type measurements (which limit the reliability of the final determination), telemetry-type systems have been proposed (Bl). In this approach the implanted catheter is connected to a miniature radio transmitter which transmits the in vivo ISE cell potentials to a receiving unit placed far from the patient or animal. By replacing the wires normally required to transmit the potential information to the external instrument, far less interference from environmental and electrical noise normally found in rooms used for surgical procedures occurs. This approach appears to hold great promise for the future of in vivo ion and gas monitoring with ISEs. 

It has been possible to interface such systems to the main production OCS for awhile, but this has been achieved via de facto standards that have made it difficult or even impossible to exchange additional information beyond the basic controlled parameters. For example, although the humidity and temperature of the production area ambient air could be measured and recorded within the OCS (via serial interface or hardwired transmitters, for instance), it has not been possible to monitor the load, temperature or efficiency of the main air-conditioning unit fans. 

Fig.9. a) Schematic diagram of the measurement unit 1. solution dispensers, 2. measuring cell, 3. inner cell, 4. membrane, 5. combination glass electrode, 6. reference filling solution, 7. temperature sensor, b) 1. Block diagram of the pH monitor 1. measurement unit, 2. buffer I, 3. buffer II, 4. rinsing solution, 5. local control, 6. preamplifier, 7. readout / transmitter. 

The widest field of battery application both in the number of batteries and in their diversity is that of portable units and domestic appliances. Typically this involves batteries of low and medium capacity from 0.01 to 100 Ah. Battery-powered electrical units include various radio sets, tape recorders, cell phones, TV sets, audio and video players, radio transmitters for civil and military use, portable flashlights for underground and other use, miniaturized devices electronic watches, hearing aids, pocket calculators, toys, some household appliances (electric shavers, measuring instruments including testers, radiation monitoring instruments, etc.), and various medical devices (cardiac pacemakers). 

Fig. lA-D. Immunofractionation of chromatin digested by micrococcal nuclease for various extents of time on an anti-poly(ADP-ribose) Sepharose column. HeLa nuclei from 10 cells were digested with micrococcal nuclease [50 units/10 nuclei at 37°C for 1 min (A), 5 min (B), 10 min (C), and 20 min (D)]. Soluble chromatin was subsequently prepared and immunofractionated on an anti-poly(ADP-ribose) Sepharose column. The columns were loaded and washed with phosphate buffered saline. Transmittance at 254 nm was continuously monitored. When no further UV-absorbing material was eluted, 6 M guanidinium hydrochloride was added to elute-bound material. The insets in each panel represent 1/50 of the DNA extracted from the pooled unbound U) and bound (B) peak fractions subjected to electrophoresis on 1.5% agarose. The gel was stained with ethidium bromide. (Taken from [10])... 

Figure 28.4 Conceptual TDLAS set-up strategies, utilizing open-path configurations (with or without retro-reflector) or closed path (with single-point or multi-point sampling, annotated as POINT and DUCT monitors in the figure). The transmitter and receiver units may include beam guiding/forming elements, such as optical fibres, telescopes, multipath reflectors, etc. The set-up also indicates the option of simultaneous calibration to a reference standard...

Simply put, instead of turning handwheels as is required by conventional machines the CNC machine control unit (MCU) sends a motion signal via a controller board to a servo motor attached to each machine axis. This causes the servo motor to rotate a ballscrew attached to the table, cross-slide or column, causing it to move. The actual position of the axis is continuously monitored and compared to the commanded position with feedback from a transmitter attached to the ballscrew. The ballscrews have almost no backlash, so when the servo reverses direction there is almost no lag between a commanded reversing motion and corresponding change in slide direction. 

Y. A. Woo, Y. Terazawa, J. Y. Chen, C. lyo, F. Terada, S. Kawano. Development of a new measurement unit (MilkSpec-1) for rapid determination of fat, lactose, and protein in raw milk using near-infrared transmittance spectroscopy. Appl Spectrosc 56(5) 599-604,2002. C. Cimander, M. Carlsson, C. F. Mandenius. Sensor fusion for on-line monitoring of yoghurt fermentation. / Sioiec 99(3) 237-248, 2002. 

An end-to-end type detector has separate transmitter and receiver units, mounted at either end of the area to be protected. A beam of infrared light is projected from the transmitter towards the receiver, and the signal strength received is monitored. End-to End type detectors require power to be supplied both to the transmitter and the receiver ends of the detector. This leads to longer wiring runs and thus greater installation costs than the reflective type device. 

A waUcover system consists of a transmitter, receiver, and a remote monitor. A battery-powered transmitter is located in the bottom hole assanbly near the front of the driU string and emits a continuous magnetic signal. The receiver is a portable, hand held unit, which measures the strength of the signal sent by the... 

A typical open-path Fourier transform infrared system for remote monitoring of air pollutants uses a single unit (telescope) that functions as both a transmitter and receiver of infrared radiation (Figure 26.7). The radiation is generated by a silicon... 

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