Hydronix Hydro-Probe XT, Руководство пользователя

Страница: 12 / 67

Chapter 1 Introduction
12 Hydro-Probe XT User Guide HD0538 Rev: 1.6.0
1 Introduction
The Hydro-Probe XT is a digital microwave moisture sensor. It uses high speed digital signal
processing filters and advanced measurement techniques to give a signal which gives a change
that is linear with the change in moisture in the material being measured. The sensor must be
installed into a material flow and will then give an online output of the moisture change in the
material.
The sensor has two analogue outputs which are fully configurable and can be internally
calibrated to give a direct moisture output which is compatible with any control system.
Typical applications include moisture measurement in biomass materials, grain, animal feed and
agricultural materials. The shape of the sensor makes it ideally suited to measure the moisture
content of materials in the following applications:
•
Bins / Hoppers / Silos
• Conveyors
• Vibratory Feeders
Two digital inputs are available which can control the internal averaging function, allowing the
sensor measurement, taken at 25 times per second enabling rapid detection of changes in
moisture content in the process, to be averaged to enable easier use in the control system.
One of the digital inputs can be configured to provide a digital output which can provide an alarm
signal in the event of a low or high reading, and this can be used to signal a high moisture alarm
or alternatively to signal an operator that a storage bin needs to be refilled.
The Hydro-Probe XT is specially designed using suitable materials to provide many years of
reliable service even in the most arduous conditions. However, as with other sensitive electronic
devices, care should be taken not to subject the sensor to unnecessary impact damage,
particular the ceramic faceplate which, whilst being extremely resistant to abrasion, is brittle and
may be damaged if hit directly.
CAUTION – NEVER HIT THE CERAMIC
Care should be taken to ensure that the Hydro-Probe XT has been correctly
installed and in such a manner to ensure representative sampling of the
material concerned. It is essential that the sensor be installed as near as
possible to the bin gate and that the ceramic faceplate is fully inserted into the
main flow of the material. It must not be installed in stagnant material or
where material can build-up on the sensor.
All Hydronix sensors are pre-calibrated in the factory so that they read 0 when in air and 100
when submerged in water. This is called the ‘Unscaled Reading’ and is the base value used
when calibrating a sensor to the material being measured. As this normalises each sensor, if a
sensor is changed then there is no need to redo the material calibration.
After installation the sensor should be calibrated to the material (see Sensor Integration and
Calibration on Page 43). For this the sensor can be setup in two ways:
• Calibration inside sensor:
Sensor is calibrated internally and outputs true moisture.
• Calibration inside control system
: Sensor outputs an Unscaled reading which is
proportional to moisture. Calibration data inside the control system converts this to true
moisture
2 Measuring techniques
The Hydro-Probe XT uses the unique Hydronix digital microwave technique that provides a more
sensitive measurement compared to analogue techniques. This technique facilitates a choice of
measurement modes. The default mode is Mode V which is the most suitable mode for
agricultural and biomass materials.