From Earlham Cluster Department
Trip To Springwood
- Temperature - 0C, 20C, 40C, digital thermometer for comparison.
- Test what's at Springwood Lake now, bring a water sample back to Mike.
- Use a standard ph 7 solution test the probe. Using the expected range check the high and low.
- Oxygen Reduction - TBD.
- Dissolved Oxygen - solutions with 0% and 100% dissolved oxygen.
- Conductivity - solution available
Sensors in the 600R
- Dissolved Oxygen
- Oxygen Reduction Potential
Parameters available in the 600R
- SpCond mS/cm - English explanation
Simple instructions and pictures documenting the process:
Before doing anything, you'll have to SSH into pmp3. Make sure to SSH into pmp3 as root.
Next, you want to go to the cron directory and comment out the first line of crontab using vi. This will prevent any scripts from running while you're trying to calibrate the sensor.
Start up minicom, this will get you directly into the sonde unit.
Type "menu" and it will give you a list of options.
Press 7 to get into the sensor menu. Make sure all of them are enabled. You can enable them simply by typing the corresponding number of the sensor you wish to enable. The table should look something like this after your'e done:
Next, head into the report menu (6). Make sure that the temp, cond (mS/cm), DOsat %, DO mg/L, pH and Orp mV options are filled in. Once again, it should look like this:
|1-( )Date||8-( )Sal ppt|
|2-( )Time hh:mm:ss||9-(*)DOsat %|
|3-(*)Temp C||A-(*)DO mg/L|
|4-( )SpCond||B-( )DOchrg|
|6-( )Resist||D-( )pH mV|
|7-( )TDS||E-(*)Orp mV|
After you're done with that, type 2 to get to the calibration menu. Type the corresponding number of what you want to calibrate.
Note that the sonde will go into a sleep mode after short period of time. You may need to type the number twice. Additionally, make sure to rinse the sonde with distilled water and wipe it down each time before you submerge it in a new solution in order to avoid contamination.
Also note that the vent hole needs to be covered for ALL Calibrations. The YSI manual mentions this once at the beginning of the calibration section, and doesn't remind you of it in any of the subsections, so it's easy to miss.
Option 1 is conductivity. This will bring up a menu asking you if you want to calibrate for a specific conductivity, conductivity or salinity. It is reccommended that you calibrate for specific conductivity. This will automatically calibrate the other two options.
Note the unit measurements of your solution, the sonde measures in millisiemens/centimeter, so unit conversion may be required.
After choosing specific conductivity, you will be asked to input the conductivity of your solution. Make sure that the probe is submerged in the solution, then input the correct conductivity and press enter.
Wait for the readings to stabilize, then press enter twice.
Option 2 is Dissolved Oxygen. This will present you with two options. Either Dissolved Oxygen Saturation Percentage, or Dissolved Oxygen in milligrams per liter.
There are two options for calibrating via percentage. Either find a solution completley saturated with oxygen, or to incompletley submerge the probe and allow the environment to become saturated with water. Either way, this should give you a oxygen saturation of 100%
Choosing saturation % will require you to enter the atmospheric pressure in mmHg (Millimeters of Mercury) you can get inHg (Inches) from our local weather station at www.cs.earlham.edu
Apply the following formula: inHg x 25.4 = mmHg
If you get it from a nonlocal weather station, you'll need to correct it. The formula is as follows: True BP = [Corrected BP] - (2.5*[Local Altitude above sea level]/100)
BP MUST be measured in mmHg for the above formula to work correctly.
Alternately, choosing mg/L will ask you what the current mg/L concentration is in the solution. This will vary depending on temperature and atmospheric pressure. You can find a table of the appropriate values at:
When polling for the dissolved oxygen data, the ./man_poll script will currentlygive an incorrect reading, as it takes several pollings of the sensor to start giving correct readings. Simply minicom into the probe and type menu 1 1 1, this will start running a discreet sampling. After about 4 or 5 readings, the probe will start giving you the correct values.
Option 3 is pH, This will bring you to a menu prompting for 1-point, 2-point or 3-point calibration. You will need a number of solutions corresponding to the number of points you wish to calibrate for.
Choose the point option that you wish to calibrate. Submerge the sonde in a solution, then input the pH of the solution, wait for the readings to stabilize and press enter twice, repeat as required.
I found that calibrating for pH 7 -> 10 -> 4 will yield acceptable results.
Option 4 is Orp, or Oxygen Reduction Potential.
Surprisingly simple. Simply input the expected ORP when asked, make sure that the probe is submerged in the solution, and wait for it to give you your results.
Wait for the results to stabilize and then press enter twice.
Yes, it's really that simple.
Note that you may not quite get the results that you were expecting. This is because of a high potential for corruption of ORP readings. Your sensor may be dirty, the temperature may be off, or there may be other problems. Refer to:
For some useful notes about ORP / ORP Calibration.
~~Testing Calibration And Finishing Up
After you finish calibration, exit the sonde unit. Failure to do so will result in a need to reboot the board before performing any more calibrations.
Simply press 0 until it prompts you to exit. After you exit the menu, exit minicom. Change directories to the script folder, then run the script man_poll [OPTION].
Don't forget to go back and uncomment the crontab when you're done.
Solutions, Mike has ordered enough of each of the ones we need. Enumerate them here.
Questions for Mike
- types of errors? Slope and something else?
- pH calibration, 1, 2, or 3 point?
To connect to Sonde directly:
- ssh or telnet to pmp, log in as root
- minicom # the port, speed, etc. are stored in a config file
- PMP and EEAP run client.pl which connects to Infobomb.
- Infobomb runs two major programs; dataparser and dataviewer.
Possible Commercial Product
- There may be general commercial products to solve this problem.
- See references
- Hydrolab's integrated systems page.
- A vertical pipe with a relatively small opening (intake) in the bottom. It is used in a gauge installation to dampen short period surface waves while freely admitting the long period waves; which can then be measured by a water level gauge sensor inside. See float well and protective well.
- Used at gauging stations
- YSI is local - Yellow Springs, OH
- Pressure? Precise water level measurement technique. What locations?
- Turbidity - [Hach] Nephelometers
- Possibly build our own as cheaper alternative (fiber optics), engineering it ourselves.
- Budgeted for 41 student weeks, or $4100 of supply money
- Redox - Self cleaning? Not sure if it's worth it. Research it.
- [Vernier Sensors]
- Possible multi-variable sensors at around $1200, not sure if we can use them for this application.
- Start work on calibration early in the summer with Corrine and her students.
- Determine required sensitivity and periodicity for each sensor.
- Mike said that sensitivity should be secondary to ruggedness and cost because the sensitivity that we are looking for is not high and most sensors will meet our needs. Thus, our approach should be to find sensors that we think will work and then send him the specs for him to OK.
- A selection of sensors from Hydrolab.
All-in-one Units, "Sondes"
- Most use batteries as the primary power source.
- Most have other features and sensors not listed in the matrix.
- All have the SDI-12 interface, which allows power and data over the same line with power management
- SDI-12 is not compatible with RS-232 because of voltage differences
- There are no interface cards for SDI-12, but there are converters for SDI-12 to RS-232 such as this one for $275 and this other one for $387.
- The user manual for all of the YSI series 6 sondes can be found here.
|Make||Model||Temp||pH||Redox (ORP)||Cond||Nitrate||DO||Sulfide||Turbidity||Specs||Data Storage||Power||Interface||Price|
|YSI Hydrodata||600 R||y||y||y||y||n||y||n||n||no spec sheet|
|YSI Hydrodata||600 XL||y||y||y||y||n||y||n||n||??||External 12VDC||RS232, SDI-12|
|YSI Hydrodata||600 XLM||y||y||y||y||n||y||n||n||384K||4 AA batteries, external 12VDC||RS232, SDI-12||$4460.25|
|YSI Hydrodata||6920||y||y||y||y||y||y||n||y||384K flash ROM||Batteries, external 12VDC||RS232, SDI-12||$6327.00|
|YSI Hydrodata||6820||y||y||y||y||y||y||n||y||??||Batteries, external 12VDC||RS232, SDI-12|
|YSI Hydrodata||6600||y||y||y||y||y||y||y||y||384K||8 C batteries, external 12VDC||RS232, SDI-12|
|Rickly Hydrological Company||Datasonde 4A||y||y||add-in||y||add-in||y||add-in||add-in||no spec sheet||??||Batteries||RS232, SDI-12|
|Sutron||5600-0703||y||y||y||y||y||y||n||y||??||4 or 8 AA batteries, 12VDC||RS232, RS485, RS422, SDI-12|
|Campbell Scientific / Hach Environmental / Hydrolab||DS5||?||y||y||y||y||y||n||y||512 KB memory||8 C batteries||RS 232, RS 485, SDI-12|
|Campbell Scientific / Hach Environmental / Hydrolab||DS5X||?||y||y||y||y||y||n||y||512 KB memory||8 C batteries||RS 232, RS 485, SDI-12|
|Campbell Scientific / Hach Environmental / Hydrolab||MS5||?||y||y||y||y||y||n||y||512 KB memory||8 AA batteries||RS 232, RS 485, SDI-12|
RTP - Ruggedized Wide Range Temperature Probe
- 9 or 12 bit resolution
- 12 foot CAT 5 cable
- Dallas Semiconductor DS18S20 or DS18B20 sensors
- uses 1-Wire communication protocol
The RTP temperature probe is designed for wide temperature range applications requiring excellent chemical resistant properties and sensor submersion.
Nitrate Levels (NO3?)
Jeff: Mike Deibel says that we could build a turbidity sensor using LEDs and fiber-optic cables without too much difficulty. He is willing to help with construction if necessary. However, we both agreed that finding an assembly that meets our need would probably be the first course of action.
- Turbidimeter Overview
- Cost Effective Turbidimeter
- Importance of Turbidity
- Nephelometric Turbidimeter
Maduna: I did some research on how to design a turbidimeter and found the following:
- Basic Turbidimeter Design
- Detailed Turbidimeter Design
- Low-Cost Four Beam Turbidimeter Design
Here is a summary of the possible equipment and designs we could use:
Here are some different battery sizes that we may want to use:
Note: The battery lifetimes are calculated based on the assumption we will be sending data every hour.
|Make||Model||Capacity (Ah)||Voltage (V)||Temp Range (F)||Lifetime (days)||Weight (lb)||Dimensions||Price ($)|
|MK||ES12-12||12||12||5 to 104||1.96||9.39||--||--|
|Odyssey||PC680||16||12||-40 to 144||2.61||--||--||--|
|Tempest||TR24-12B||24||12||5 to 104||3.92||--||--||--|
|CSB||GP12400||40||12||5 to 104||6.54||--||--||--|
- Heating and cooling.
- None of the charge controllers in the amp range that we are interested in have a way to export battery level information.
- Probably the best solution for knowing the battery level is to build a simple circut that will transform the 0-12 volt range of the battery into the 0-3.3 volt range of the analog IO of the board and use this voltage as a way of finding the battery charge level.
- PWM = Pulse Width Modulation.
- LVD = Low voltage disconnect.
- Temperature compensation can be either integrated into the controller which assumes that the controller and the battery will be in the same box, or remote which allows for a temperature probe to be placed on a battery that is not with the controller.
- The Phocos model in the matrix is the same as the one currently on the pmp1.
- Here is a really good site for finding manufacturer information and product details for charge controllers and other solar stuff including panels.
|Make||Model||Specs||Manual||Voltage||AMP||PWM||LVD||Temp comp||Charge display||Price|
|Morningstar||SunKeeper-6||12||6||Y||N||integrated, opt. remote||One LED||$63.00 (Solar Panel Store)|
|Sundaya||Apple 5||none||none||??||5||?||Y||?||Many LEDs||$22.65 (Sundaya)|
|Phocos||CML05-2||none||none||12/24||5||Y||Y||integrated||Some LEDs||$25.00 (Real Goods)|
|Steca||PR 505||12||5||Y||Y||integrated?||Three LEDs||--|
Single Board Computers
- Power over ethernet? not supported by TS or Gumstix.
- Heating and cooling.
|SBC||Type||DIO lines||A/D Converter||Price|
|TS-7200||ARM||20||8 ch. 12-bit (opt)||$149.00|
|TS-7250||ARM||20||5 ch. 12-bit||$149.00|
|TS-7260||ARM||30 & XDIO*||2 ch. 12-bit||$179.00|
|TS-7300||ARM||55 (35 XDIO)||n/a||$219.00|
|TS-7400||ARM||20||4 ch. 8 bit||$129.00|
|TS-5500||x86||38 (IRQ)||8 ch. 8 bit||$319.00|
- eXtended Digital I/O functionality including pulse-width modulation, quadrature and edge counting, and pulse timing with IRQ/DRQ support.
- EP9301 User's Guide referenced in the TS-7260 manual for ADC programming.
TS-DIO64 Digital I/O Board
TS-DIO64 Digital I/O Board, which is a 8-bit PC/104 (standard format) peripheral board that provides 64 digital I/O points (32 inputs plus 32 outputs). Up to 4 TS-DIO64 boards may be installed into a single system, enabling up to 256 DIO points (128 inputs plus 128 outputs). The TS-DIO64 DIO functions are compatible with any PC/104 SBC including all the Technologic Systems ARM and X86 products. Consists of the following parts:
- 64 Digital I/O points - PC/104 peripheral board $69
- Optional 512 Kbyte battery-backed SRAM $40
- Optional 1M battery-backed SRAM $60
- 34 pin 18" ribbon cable $7
Total cost for all parts: $176
PC/104 GSM Cellular Modem Peripheral Board
PC/104 GSM Cellular Modem Peripheral Board, provides internet access through the GSM cellphone network. Standard baud rates up to 115.2 Kbaud. 230 Kbaud supported in x2 mode. Works with all TS boards. Takes standard SIM card with accompanying cellphone service costs. Optional capacitor for backup of modem memory on reset and startup. Consists of the following parts:
- Cellular modem peripheral board (modem not included) $79
- Sony Ericsson GR64 quad band RoHS GSM cellular modem $99
- Optional Panasonic Gold 10 farad capacitor $8
Total cost for all parts: $186
You forgot to uncomment the crontab, didn't you? That's OK. It's not too late to go back and do it.