Data logging multiple channels
If you want to measure more than one item (for example, multiple slime tube) at once or record multiple measurements on the same living structure (for example, different branches of plant) you’ll want to record multiple channels (i.e. one differential voltage measurement per channel).
If you are new to measuring electrical signals easier to start with single (rather than multiple) measurements.

Guide to manual data logging multiple channels

CoolTerm

CoolTerm (freeware) serial port terminal program can be downloaded from

http://freeware.the-meiers.org/

 

Close Arduino IDE Serial Monitor/Plotter before using CoolTerm as this may block it from working correctly.

 

After installing CoolTerm select ‘Connection’ then ‘Options’ as shown below:

Then under the ‘Options’ menu select ‘Port’ and click the ‘down arrow’ to show list of communication ports (Com 1, Com 5, COM 12 …) the numbers will be different on each computer. Select the port being used to communicate with PhyLink, see below:

If you are unsure which Port number PhySense is using look under ‘Tools’ then ‘Port’ with Arduino IDE then close Arduino IDE

Select ‘Connection’ then ‘Options’ then drop down menu under ‘Baudrate’ as shown below:
The default baud rate is 9600. To improve performance PhyLink is usually set to 1200.
Select ‘Connection’ then ‘Connect’ as shown below:
The voltage measurements should appear as a long column of (changing) numbers, see below.
If the numbers are all zero trying touching an input wire with your finger to see if they change. If they don’t change or you don’t see any numbers something has gone wrong and you’ll need to check settings.
Select ‘Connection’ then ‘Capture to Textfile’ then ‘Start’ as shown below:

 

Choose file name for text file (*.txt) and folder to save in, as shown in example below:

 

When you want to stop saving measurements to text file select ‘Connection’ then ‘Capture to Textfile’ then ‘Stop’ (or Pause) as shown below:

 

The saved text file with contain the data (voltage measurements) which can be plotted and analysed. You can open/view the data with Notepad or Word, see example below:

 

The data should be a long column of numbers which change. If the numbers are all zero or don’t change something has gone wrong and you’ll need to repeat measurement .

 

To simultaneously save TWO or MORE measurement channels to text files press ‘New’ and an additional terminal window will open, see below:

 

The ‘Port’ number on the new Terminal window will be different to the ‘Port’ number on the original Terminal window, as shown below (COM 7 and COM 8):

In the example above, the numerical values from PhyLink are being compared against graphical values from PICO ADC-24.

 

How many PhyLink can be connected

The maximum number of PhyLink units than can be simultaneously connected depends on the computer/device. For example, most Desktop PCs have at at least 2 USB ports on the front and 4 or 6 at the back. However, other device such as keyboard, mouse, etc may use USB ports.

Please note, unpowered or passive USB hubs do not have an external power source and only pull power from the computer’s USB port. Therefore don’t use unpowered HUB(s) to connect lots PhySense units to computer/device.