Valeport MIDAS WLR Water Level Recorder

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  • Rental
  • Sale (new & ex rental)

Valeport MIDAS WLR Water Level Recorder – Available for rental, hire and purchase from Ashtead Technology.

The MIDAS WLR is a precision water level recorder, designed for use in both autonomous, or real time deployments.  Fitted with a 0.01% accuracy pressure sensor and accurate PRT temperature sensor as standard, the MIDAS WLR features a variety of operating modes from rapid 8Hz continuous sampling to power saving burst modes for long term monitoring.  The instrument is available in both shallow water acetal or deep water titanium versions, and is suitable for fixed or in-line mooring, with a variety of communications options built in.

The pressure 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.

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.

Supplied with mooring cage, Subcon switch plug, 3m communications lead, USB adaptor, DataLog Express software, manual, tool kit and transit case.

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Technical specifications

TypeTemperature compensated piezo-resistive cell
Range200 dBar
TypeTitanium housed PRT
Range-5°C to +35°C
MEMORYStandard memory is 16Mbyte FLASH, which is capable of storing approximately 2.7 million records. The memory is non-volatile, so data and co
RS232Up to 200m cable, direct to serial port via USB adaptor
RS485Up to 1000m cable, addressable half duplex comms
Baud Rate2400 - 115200 (FSK fixed at 19200, USB 460800)
Protocol8 data bits, 1 stop bit, No parity, No flow control
Internal8 x C cells, 1.5v alkaline or 3.6v lithium
External9 - 30vDC
Power0.3W (sampling), <1mW (sleeping)
Battery Life90 days operation (alkaline) or 215 days (lithium) based on a 40 second burst sample every 10 minutes
ConnectorSubconn MCBH10F
Depth Rating500m, sensor range permitting.


Instrument88mmØ x 550mm3.5" x 21.6"7kg15.4lbs
Cage750mm x 140mm x 120mm29.5" x 5.5" x 4.7"