Q: How is the NETSCANNER 9216 constructed?
A: The 9216 combines integral pressure transducers with a miniature data acquisition system to provide a multichannel pressure scanner. The integration of the microprocessor with the pressure transducers provides several benefits in addition to the compact nature of the intelligent pressure scanner. This pre-engineered approach to pressure acquisition offers higher system accuracy, unlike individual pressure transducers where stated accuracy is met only if the many user-considerations are addressed, especially with respect to temperature effects and zero drift. The Model 9216 Ethernet intelligent pressure scanners output pressure data in engineering units, digitally compensated for offset, span, non-linearity and temperature effects. The integral pneumatic manifold permits on-line rezero and even span calibration capability under microprocessor control.
Q: How is the pressure scanner compensated?
A: Silicon piezoresistive pressure sensors are low cost, miniature pressure sensing elements suited for packaging individually for each pressure port. However, like most sensors, they are affected by temperature. Since these effects are repeatable, sensor calibration over temperature and pressure can be used to characterize and correct these errors. Each silicon pressure sensor is packaged along with a nonvolatile memory device (EEPROM) and a temperature sensor in its own miniature field-replaceable housing. The transducers are factory-calibrated over the specified pressure and temperature spans. The resultant calibration data, along with the pressure range and serial number of the sensor, are stored in the integral EEPROM. The microprocessor utilizes this information to compensate transducer outputs for offset, sensitivity, nonlinearity, and thermal effects before transferring pressure data to the host computer. Should a transducer be replaced, the microprocessor will automatically recognize the new transducer upon power up and extract the calibration information from the EEPROM.
Q: Does the NETSCANNER 9216 contain internal clocks?
A: The 9216 contains an internal real time clock (RTC) for keeping system date and time. This clock is factory initialized to UTC0 time. The 9216 also has the ability to continually synchronize its internal RTC to either an NTP server or IEEE 1588-2008 Precision Time Protocol (PTPv2) grandmaster clock if they are present and accessible on the 9216’s network. As part of the 9216 data stream configuration, data samples may optionally include an absolute time stamp indicating when the data sample was acquired. It is also possible to configure 9216 data streams to start autonomously at a set absolute time. This is useful for initiating data streaming synchronously through a large 9216 configuration without the use of the hardware trigger signal.
Q: How do I use the manifold? Does this pressure scanner feature re-zero and span calibration?
A: Download the datasheet for a complete overview with outlines. Model 9216 intelligent pressure scanners incorporate a unique manifold enabling online pneumatic rezero and span calibrations to maximize transducer accuracy. The manifold can be specified with either a common pressure reference or an individual pressure reference (true differential) per channel. Both configurations feature built-in purge and leak check capability of the pneumatic input lines as standard. The manifold utilizes a proprietary "O" ring seal providing years of leak free operation. If required, "O" rings can be replaced in the field using common tools.
