d-Plucker

The d¹Plucker and d⁴Plucker are small, low cost unit that instantly convert vibrating wire (VW) transducers such as load cells, stressmeters and piezometers, into d-Tech compatible instruments.

These VW sensors then become compatible with YieldPoint’s data loggers and radios.

1 channel and 4 channel versions are available. d-Plucker enables YieldPoint’s low cost digital peripheral devices to read (d-Reader), store (d-Logger) or transmit (d-Mesh) data from VW sensors.

The user simply connects the leads of the VW sensor to a terminal block housed inside the unit and then treats the sensor like any other YieldPoint d-Tech instrument. The unit outputs the temperature recorded by the thermistor in ^oC (0.1^oC resolution) and the period of vibration of the wire in µS (0.1µS resolution).

Features:

• Plug-and-play solution for VW sensors
• Inexpensive and versatile
• Allows VW sensors to interface with YieldPoint d-Reader, d-Logger data-loggers and d-Mesh networks
• 500-6000Hz (0-5Vdc) square wave sweep. Output is in microseconds (µS) or in digits.
• Temperature output from thermistor with 0.1C resolution.
• Digital RS485 Output (9600,8,N,1), with Unique Instrument ID, SensorType, and output data.

Specifications:

• Range (F.S.): 166-2000µs period measurement, Temp: -40 to 125^oC
• Core Technology: 20MHz microcontroller providing 0-5V 500-6000Hz sweep
• Output Signal: RS485 (9600,8,N,1) ASCII encoded signal comprising: Unique Instrument _ID, Sensor_Type, Temp (^oC) and Period (µS) data
• VW Resolution: 0.1µs with hand held readout.
• Displ. Accuracy: – better than +/- 1µs
• Temp. Range: –40 – 125^oC
• Temp. Accuracy: +/- 1^oC –Digitally trimmed at 0^oC and 25^oC
• Temp Resolution: 0.1^oC

Technology:

The d⁴Plucker uses a proprietary algorithm to locate the resonant frequency within the range 500Hz to 6000Hz. An internal switch is used to select 3 different frequency ranges based on the type of instrument used.

Using the d-Reader it is possible to quickly read the transducer. Using the d¹Logger or d⁴Logger it is possible to log data from 1 or 4 VW sensors over a 100 day duration.

Using d-Mesh it is possible to transmit data over an existing TCP/IP network using either Ethernet or WiFi. A unique digital ID is assigned to each d⁴Plucker.

The output signal from the d-Plucker is a digital RS485 signal (9600,8,N,1) with ASCII encoded Sensor_ID, Sensor_Type, Temp and period.

Telemetry:

Manual Readouts:

Readout can be made using YieldPoint’s low cost manual interrogation unit (d-Reader), with a backlit LCD. The Unit displays the Sensor_Type and Sensor_ID and outputs the temperature and VW data directly in oC and µs.

The d-Viewer Module provides USB connectivity so that the d-Plucker can be read with using a LapTop or Tablet (d-Tab) PC. If power is available a low cost NetBook computer can be transformed into a data-logger.

Automated Data Retrieval:

The d-Logger (32Mb of memory) can collect up to 10,000 readings from the d-Plucker over a period up to 1 year. Download to a PC is with a USB download cable (order separately).

Plug-and-Play networks of instruments can be created using YieldPoint’s d-Mesh technology. A low-cost d-Mesh node can connect 4 instruments to a TCP/IP network over Ethernet or WiFi. This solution saves time and money by transmitting data directly to an engineer’s desktop computer.

Applications:

• Monitoring pillar stress changes using vibrating wire BPCs.
• Monitoring pillar stress changes using vibrating wire stressmeters.
• Monitoring strain in structural elements using welded vibrating wire strain gauges.
• Monitoring the loading of structural elements such as posts and pillars
• Monitoring piezometer arrays.

Measuring stress changes in a Secondary Rock Pillar

Measured stress changes by two orthogonal Borehole Pressure Cells installed in production hole for a secondary stope pillar. BPCs attached to d¹Plucker ( red -longitudinal orientation, blue- transverse). Recorded with d-Logger data-logger.