Standard 1. Mine Safety and Health Admin 1. Legacy Part Number, 33 ft Cable 1. Lightening Protected Amplifier Housing 1. Legacy Part Number 1. Trim Pots 1. Rangeable 1. Pressure Type. Gauge Absolute Sealed Gauge Differential Vacuum Compound Gauge Barometric 8. Not Applicable 1. Electrical Output. USB 5. Selectable 4. RS 2. Data 1. Cable MILI P Mini DIN C M12 Conduit Terminal Block Submersible Cable 7. Hermetic Pin Termination 6.
Submersible Cable with Conduit 4. Pins 4. DIN A 3. Cable with Conduit 2. MILI P 1. Internal Screw Terminals 1. Internal Terminal Strip 1. Conduit with Cable 1. T 1. Bad part number 1. Pressure Port Type. NPT Male NPT Female BSPP Male High Pressure FC 7. UNF Male 7. BSPP Female 7. Barbed Fitting 7. NPT MxF 5. UNF Female 4. Tube 5. Tri-Clamp 3. Submersible 5. Flush 3. ISO Male 1. ISO Female 1. High Pressure NS-2 1.
Output Signal. Current Voltage Digital 6. When installing transducers, refer to standard industry torque data for thread size and material type. Multiple transducers can be excited from one power supply. The number of transducers that can be used is simply determined by the current draw of each transducer and the current capacity of the supply source.
The sum of the current draw of the transducers can not exceed the total current capacity of the supply. For example, if you have 50 transducers drawing 13 milliamps, you will need a power supply having at least milliamps 50 x There is also nothing wrong with powering just one transducer with a power supply having high current capacity. Figure 6. Converting current into voltage for instrumentation set up for voltage.
Pressure transducers that output milliamp signals can connect to multiple devices in series. The fact that they can transmit signals over long distances without interference makes it easier to connect a milliamp-signal device to multiple instrumentation units. This diagram illustrates the correct wiring. One of the great advantages of a current signal is the simplicity in setting up a multi-instrument system. Long distance transmission from instrument to instrument without electrical interference make multi-instrument systems easy.
For example, a material test center may have one control room for all the different test labs, enabling operation from one central location. Instrument calibration and troubleshooting are simple in a multi-instrument current loop.
The only limitation for the number of instruments is the amount of voltage from the power supply driving the current loop. The minimum voltage required is determined by Ohms law, V-IR voltage equals current times resistance. This is shown and explained in Figure 4. Wiring a voltage or millivolt signal to multiple instruments also can be done, but is not as easy and does not have the calibration and troubleshooting advantages inherent in a current loop system.
The voltage or millivolt signal can be wired in parallel to multiple instruments as shown in Figure 5. This method assumes a very high input impedance in the instruments being wired. If this is not the case, an analog output can be used instead to retransmit the signal. In measuring multiple pressures, it is a common mistake trying to use multiple transducers, a switching device, and just one panel meter, thus saving money on multiple panel meters or any other instrumentation. The problem is that each transducer has a unique zero point and the readout only has one zero screw.
In most cases, this larger error is intolerable. The correct method of using multiple transducers with one readout device is to use transducers that have built-in zero and span adjustments screws, the same output voltage or current , and the same pressure range. Each transducer is adjusted by applying a known pressure, so that they all have identical outputs.
When they all have identical outputs, the meter is scaled and a switch can be used. Figure 6 Another solution to using multiple transducers with one readout is to use a scanner instead of meter and a switch. There are many types of scanners.
The type of scanner that works with multiple pressure transducers must have independent scaling on each channel. Some scanners, besides having independent scaling on each channel, also offer independent current, voltage, or millivolt inputs to each channel.
These types of scanners enable you to use transducers with different outputs as well as different pressure ranges with the same instrument.
Figure 2. Typical wiring configuration for voltage output transducer -excitation and -signal are common Figure 1.
Typical wiring configuration for millivolt output transducer Figure 3. Typical wiring configuration for current output transducer Figure 4. Multi-instrument mA current loop panel meters, chart recorder, computers, etc. Multiple instruments wired in parallel to a voltage output transducer. Most instrumentation is set up to receive voltage.
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