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ISUS V3 Nitrate Sensor

ISUS V3 Nitrate Sensor - Discontinued

ISUS V3 nitrate sensor is a real-time, chemical-free sensor designed to overcome the traditional challenges associated with reagent-based nitrate analysis in aquatic environments.

ISUS V3 nitrate sensor is a real time, chemical free sensor designed to overcome the traditional challenges associated with reagent-based nitrate analysis in aquatic environments. The ISUS technology uses advanced UV absorption technology to provide accurate nitrate concentration measurements in real-time.

Applications:

  • Long term nitrate monitoring
  • Water quality assessment in estuaries and coastal environments
  • Freshwater nutrient loading studies
  • Watershed TMDL assessment
  • Phytoplankton bloom prediction
  • Wastewater monitoring

The MBARI-ISUS technology was developed by Dr. Kenneth Johnson  and Mr. Luke Coletti of the Monterey Bay Aquarium Research Institute and published as Johnson and Coletti 2002, In situ ulrtaviolet spectrophotometry for high resolution and long-term monitoring of nitrate, bromide and bisulfide in the Ocean.

The new ISUS V3 now comes with full speed USB capability and the ISUSCom windows-based software package.  ISUSCom allows users to log and view real time data, download files, set sampling schedules, and much more all through an easy to use interface. (MBARI).

 

PERFORMANCE

Accuracy: ± 2 μM (0.028 mg/l) or ± 10% of reading, whichever is greater
Detection range: 0.5 to 2000 μM *(0.007 to 28 mg/l-N)
Thermal Compensation: 0 to 40 °C
Salinity Compensation: 0 to 40 psu

 

OPTICS

Path length: 1 cm
Wavelength range: 200 - 400 nm
Lamp type: Deuterium
Lamp lifetime: 900 h

 

ELECTRICAL CHARACTERISTICS

Input voltage: 6 - 18 V (Non-isolated power input from batteries)
19 - 75 V (Isolated power input)
11 - 36 V (Optional isolated power input)
Power consumption: 7.5 W (0.625A @ 12V)
Data storage: 256 MB
Sample rate: 1 Hz
Telemetry options: Analog output 0 - 4.096 VDC
Analog output 0 - 4.096 VDC
Isolated RS-232 - RS-485 serial output
User selectable baud rates available (Default 38,400 bps)
Data Download Options USB, RS-232

 

PHYSICAL CHARACTERISTICS

Depth rating: 1000 m/ 200m
Length: 24 inches (608 mm)
Diameter: 4.5 inches (114 mm)
Weight: 11.0 lbs in air (5.0 kg)
1.5 lbs in water (0.7 kg)
Housing material: Anodized Aluminum/ PVC
Operating temperature: 0 to 40 °C

 

Specifications may change without notice. June 2010

ISUSCom is a complete configuration and operation program for the Satlantic ISUS V3 nitrate sensor.

Configure and control all aspects of your ISUS with ISUSCom, and easy-to-use graphical program that lets you:

  • configure ISUS for deployment
  • transfer data files at full USB speed
  • set sampling schedules
  • perform field calibrations
  • visualize and capture data in real-time
  • post-process previously logged data files
Version 2.1.6 released April 18, 2013

ISUSCom 2.1.6 now comes with a handy terminal input for issuing serial commands directly to ISUS. It also fixes a time zone calculation error that was appearing in the output of the raw data conversion function. The USB driver and operating platform have been updated to ensure full compatibility with Windows 8.

Please note that ISUSCom 2.1.6 requires a current version of the ISUS V3 firmware, which will be uploaded to your instrument when the software is installed. If your instrument is running firmware versions 3.0.3 or older, please support for assistance.

ISUSCom-2.1.6-b98-x86.exe for Windows 7/8/10


Can an ISUS V2 be used with ISUSCom?

No. An ISUS V2 does not have the correct hardware to be used with ISUSCom. If you have an ISUS V2, and wish to use it with this software, please contact Sea-Bird Scientific Customer Support to discuss upgrading your ISUS.

How does the free calibration differ from the fresh water calibration?

The included class-based calibration coefficients are average coefficients obtained from our library of historical calibrations. The historical coefficients that are averaged to create the class based coefficients vary by about 10%.

"Reprocess Nitrate Data" function under ISUSCom Processing Menu

The "Reprocess Nitrate Data" tool in ISUSCom allows the user to select a calibration file and a raw file.

The resulting ASCII file contains a column for the original Nitrate concentration as calculated by the ISUS, using the calibration file onboard the sensor, and a column of recalculated Nitrate using the chosen calibration file.

How does the ISUS compensate for long term drift?

Because the ISUS is an active optical instrument with an internal UV light source and spectrometer, gradual changes in the baseline spectra can occur. To check for instrument drift, we recommend users check the baseline prior to deployments by sampling an aliquot of ultra pure de-ionized water (DIW). To do this, first clean the probe tip and warm up the instrument for 8-10 minutes. Then log 1 minute of data with the probe tip submersed in DIW, making sure that there are no bubbles present on the probe tip. If the nitrate reading for the DIW sample is >-2 or <+2 uM, the instrument has not drifted significantly. If the nitrate reading is outside this range, the instrument has drifted and should be corrected by updating the reference spectrum in the cal file. For V3 instruments, the ISUSCom software has a function to update the cal file. For V1 & V2 instruments,  the ISUSCal program is required. After uploading the new cal file to the instrument, it is a good idea to run another DIW check to make sure the procedure has worked.

I am planning on doing a mooring deployment which requires relatively tightly spaced sampling. Are there any issues I need to consider when making a schedule file?

There are three main points to consider when making a new schedule:

  • Power: if you are using a battery to power the ISUS, make sure you have enough battery capacity to cover the schedule you intend to use. The ISUS draws about 7 watts of power with the lamp turned on

  • Memory: make sure the scheduled frequency and duration don't create more than 256 MB of data. The ASCII full frame is 1675 bytes

  • Lamp time: the UV lamp used in the ISUS has an effective lifetime of ~ 1000 hours. It is usually a good idea to conserve lamp hours by only collecting meaningful data


How is the ISUS V3 different from V2?

The most significant improvement with the V3 is the addition of full USB communications and data transfer ability. The V3omes with the ISUSCom software, a new Windows-based program designed to make the instrument setup and file transfer processes easier. V3 users no longer need to use HyperTerminal and Y modem transfers to retrieve data. It can all be done now at high speed with one cable in a professional windows environment. 

The ISUSCom software also offers users the ability to update the instrument sampling schedule for mooring deployments, perform in field calibrations, view and log data. It effectively consolidates functions previously performed by HyperTerminal, ISUSCal, ISUSSchedule and SatView into a single, simplified program.

How does the ISUS compensate for long term drift?

Because the ISUS is an active optical instrument with an internal UV light source and spectrometer, gradual changes in the baseline spectra can occur. To check for instrument drift, we recommend users check the baseline prior to deployments by sampling an aliquot of ultra pure de-ionized water (DIW). To do this, first clean the probe tip and warm up the instrument for 8-10 minutes. Then log 1 minute of data with the probe tip submersed in DIW, making sure that there are no bubbles present on the probe tip. If the nitrate reading for the DIW sample is >-2 or <+2 uM, the instrument has not drifted significantly. If the nitrate reading is outside this range, the instrument has drifted and should be corrected by updating the reference spectrum in the cal file. For V3 instruments, the ISUSCom software has a function to update the cal file. For V1 & V2 instruments, the ISUSCal program is required. After uploading the new cal file to the instrument, it is a good idea to run another DIW check to make sure the procedure has worked.

Should I provide my ISUS or SUNA with a warmup time before recording data?

We recommend updating the ISUS or SUNA's reference spectrum portion of the calibration with the instrument in the same state it will be used in the field. To update the reference spectrum, you will have to run the calibration feature in ISUSCom or UCI using a pure water sample.

For best results, we recommend the following:

1. For profiling situations, when the instrument will be run for extended times, the reference spectrum should be updated after the sensor has been run for several minutes. This will allow the Nitrate reading to stabilize.

2. For moored applications, we recommend that the instrument only be run for a short duration to collect the pure water data during the calibration. Data collection in the field should only have the instrument run for 20 seconds per acquisition.

My ISUS is running slower than normal. What is causing this?

An ISUS should run at approximately 1Hz. Check the amount of storage space left on the internal memory; old data files should be downloaded or deleted from the disk on a regular basis. Additionally, the Messages.log files should be periodically removed. Download and/or delete these files to restore normal operation.

Anti-fouling guard

The ISUS anti-fouling guard is a copper based passive fouling prevention guard. The anti-fouling guard provides a reliable and affordable approach to increase deployment time, decrease operating costs, and collect high quality data for mooring applications. 

 

 

Flow cell

The ISUS flow cell is designed to adapt the ISUS for flow through operations on moorings with pumped flow, ship-board underway systems or for laboratory testing and calibration. The flow cell threads over the retro-reflection probe tip and tightly seals against the instrument endcap. Nylon barbed fittings are provided to connected the flow cell to available pumped flow.

 

Alkaline Battery Pack

Satlantic's reliable and user-friendly Alkaline Battery Packs are available in 102 Ah and 51 Ah capacities. The design of the internal battery compartment allows the user to easily change the D-Cell batteries with off-the-shelf replacements. The battery packs consist of an anodized aluminum pressure case, a D-cell battery compartment and a removable end-cap.