Sensors
The MIDAS WLR comes with a choice of pressure sensor ranges to suit the depth requirement of the operator. The sensor used is a revolutionary piezo-resistive cell with internal temperature compensation, giving the accuracy and resolution levels normally associated with a resonant quartz sensor, but with increased durability, stability and recalibration intervals.
Pressure
Type: Temperature compensated piezo-resistive cell
Ranges: 100, 200, 300 or 500 dBar
Precision: ±0.01%FS
Resolution: 0.001%FS
Temperature
Type: Titanium housed PRT
Range: -5°C to +35°C
Accuracy: ±0.01°C
Data Acquisition
In line with other Valeport “MIDAS” series instrumentation, the MIDAS WLR samples data points at up to 8Hz, and has a variety of operating modes including continuous data output, triggered sampling, and data bursting. The typical configuration for this instrument is to sample data in a burst mode for a user defined integration period, selectable from a single sample up to 600 seconds. This data burst may then be repeated at a suitable regular interval, from once per minute to once per day.
Sampled data may either be recorded in its entirety, or simply averaged and recorded along with standard deviation data. It is usually recommended that data is averaged over an integration period of 40 seconds to filter the effects of any wave activity.
Note that Valeport’s distributed processing concept allows the pressure data to be automatically converted into the user’s choice of units, including Metres or Feet of water.
Memory
Standard memory is 16Mbyte FLASH, which is capable of storing approximately 2.7 million records. The memory is non-volatile, so data and configuration are retained in the event of power failure.
Communications
RS232 Up to 200m cable, direct to serial port via USB adaptor
RS485 Up to 1000m cable, addressable half duplex comms
Baud Rate: 2400 - 115200 (FSK fixed at 19200, USB 460800)
Protocol: 8 data bits, 1 stop bit, No parity, No flow control
Electrical
Internal: 8 x C cells, 1.5v alkaline or 3.6v lithium
External: 9 - 30vDC
Power: 0.3W (sampling), <1mW (sleeping)
Battery Life: 90 days operation (alkaline) or 215 days (lithium) based on a 40 second burst sample every 10 minutes
Connector: Subconn MCBH10F
Software
System is supplied with DataLog Express Windows based PC software, for instrument setup, data extraction and display. DataLog Express is licence free.
Physical
Instrument: 88mmØ x 550mm, 7kg (acetal), 11kg (titanium)
Cage: 750mm x 140mm x 120mm
Depth Rating: 500m (acetal), 6000m (titanium),
Sensor range permitting.
Shipping: 100 x 18 x 49cm, 20kg (acetal), 24kg (titanium)
Ordering
0730043 MIDAS WLR in acetal housing with 0.01% pressure sensor & PRT temperature sensor. Supplied with mooring cage, Subcon switch plug, 3m communications lead, USB adaptor, DataLog Express software, manual, tool kit and transit case.
Specify pressure range (100, 200, 300 or 500dBar)
0730046 MIDAS WLR in titanium housing with 0.01% pressure sensor & PRT temperature sensor. Supplied with mooring cage, Subcon switch plug, 3m communications lead, USB adaptor, DataLog Express software, manual, tool kit and transit case.
Specify pressure range up to 6000dBar
