Better by design What You Get        Sensor The VTX423 sensor has a vibrating cantilever beam sensing head mounted on a 1" NPT male thread for direct insertion into a process line.  Electronics to power the sensor and process the response is in the attached housing.  The tank version VTX423T has an additional bulkhead flange that enables direct insertion into a tank.  It is available with stem lengths suitable for most tank sizes.              Display [optional] The model D422 is a 1/4 DIN desk top or panel mount display with high intensity, four digit, seven segment indications of viscosity and temperature.  24Vdc power for the display and sensor is created by a universal mains adaptor [provided].  A DB9 serial port interface enables computer data logging and sensor configuration.  The display face is sealed against water and dust.  The body is extruded aluminum.  The face is 0.25 inch thick acrylic with an HB flame rating face. If the display is not used, it is up to the user to provide clean 24Vdc power to the sensor.        How it Works        Vibrating Cantilever Beam The operating principle of the VTX423 sensor involves dynamically squeezing the measurement fluid between the tip of a vibrating cantilever beam and a rigid surface.       The advantage of this patented "pinch" technique is that the decay of the beam vibration is determined by the viscosity of the fluid in the gap, even if the fluid is not very viscous.  Using this pinch amplification we can make the beam tip small, increase accuracy, and reduce costs. There are no shuttle bobbins to jam, no motors with rotating seals, no lead-based piezoelectric materials, and no rare earth magnets.  Just a coil, a platinum RTD for temperature detection, and a magnetic circuit.  The simplicity and elegance of the design means more reliability, smaller size and less cost. Fourth generation devices have all welded construction and only two corrosion resistant wetted materials, 316SS and mumetal.  Excitation of the beam and detection of its oscillation and decay is all done electromagnetically using variable reluctance techniques implemented with high reliability surface mount integrated circuitry. For additional details refer to U.S. Patent 6,668,621.   Installation        In-Line Sensor The tip of the sensor has a 1" NPT pipe thread for direct insertion into a one inch bypass line.  In most cases it's advisable to add shut off valves for ease of service.       We want good flow through the bypass, so choose a location where there is a significant pressure drop,  such as across a restriction or elbow.    If the process line can be periodically shut down,  then the sensor can be installed directly into the line using a 1" NPT weld saddle. A reducing Tee can also be used for lines which are not one-inch but close, for example, 1.5" up to 3" [30-60mm].       Tank Installation The VTX423T configuration has a flange on the base of the housing for insertion into a 1 5/8" access hole.  The flange has a sealing gasket.  The internal length can be 5", 7", 9", 11",15", 21", 27" [13, 18, 23, 30, 38, 53, 69 cm].        Display Panel Mount The D422 display is a 1/4 DIN configuration.  To mount it in a panel, first cut a 92mm x 92mm access hole.   Next remove the side rails, insert the panel from the front, and then restore the side rails. Wiring         Sensor, Display, Power and Serial Port Interconnect requires a six conductor shielded cable, 20-24 AWG stranded, with the shield runner connected to the ground wire on both ends. With the cover open, there is a 1x6 interconnect header.   Reading from top to bottom in the illustration, the connections are  Ground,  Rx,  Tx, ViscoMa, TempMa, and 24Vdc. On the other end, connections to the display are the same sequence. In this case, Green, Brn, Blu,Blk, Wh, and Red respectively. On the display there are also four independent connections for the sourced 4-20ma output corresponding to viscosity and temperature.  Connect them to a current meter or a precision reisistor across the input of a high impedance voltage detector.  Limit the loop resistance to 300 ohm or less. If you have a clean, reliable ground, connect it to the ground lug.  This ground will be carried to the sensor body.       If you want to isolate the sensor body from the display ground, cut the grounding jumper on the circuit card upper right corner in this view. To run the sensor and display connect the ac adaptor provided with the display to a 90-240Vac power source then plug the 2.5mm plug into the "24Vdc" jack on the back.  To connect a computer for data logging or sensor configuration adjustments, connect the serial port to the "RS232" 9-pin connector.  See Technical Notes 11168 "Config- uring Hyperterminal" and 10354 "Serial Port Com" fo details. Ordering, Evaluation Period and Payment Terms  Based on passing a simple credit check or a past payment history, our terms are 60 days.  During that time you can evaluate the system in your application. We will work with you to assist in that process. After sixty days you can either return the system or submit your payment. To receive a formal quote either click on the "contact" link above and fill out the inquiry form, or call the factory at 781-933-6116, fax us at 781-305-3736 or email us at  Our prices are available by clicking the "Prices" link above. If you have any questions regarding use of the system, prices, or terms, be sure to contact the factory.