hello to all.
so i have a labjack u6 with an adaptor connected to 7 different loadcells who measures tomato plant in a growth room with steady tempeture over night.
everything works great with just one problem that i cant figure out.
every day at exactly 7:00PM there is a big "jump" at the output.
so if over night i see the weight of the plants loses about 2-4 grams every 12 minutes. every day at 7:00PM the output says the plant gained 2 grams.
someone have any reasonable explanation ?
Thanks in advance.
File Attachment:
.png%3Fitok=PHGBxf6M "EEV Blog Reviews LabJack T7-Pro & Software Tools")
.jpg%3Fitok=B1YcuDFK)
.png%3Fitok=Ybt-OlgU "LabJack + JEDI One Can Create a Powerful Distributed DAQ Ecosystem")
I assume you are doing differential readings of the raw voltages from these load cells?
What are you using for excitation voltage for the load cells? See Section 1 in post #13 here:
https://forums.labjack.com/index.php?showtopic=4376
Log the raw voltages instead of or in addition to your scaled values so we can look at raw voltages, and then start with these measurements and let us know what you see at 7pm:
On one channel, disconnect your signals and instead jumper both AIN to GND.
On another channel, leave your signals connected but remove the load cell from the load. For example just set the load cell on a desk so the load is 0 and you know the load is not changing.
Use another analog input to measure the value of the excitation voltage. Sounds like you are using all 14 analog inputs, so might have to disconnect another load cell to free up a couple channels. Note that this will likely be a single-ended reading, not differential, and you will likely have to change the range of this channel to +/-10V, not the +/-0.1 or +/-0.01 range you are using for the load cells.
Note that the email notifications sent to you (Yowiz) by this forum system are bouncing. We get a message from Office 365 that starts with the following:
A custom mail flow rule created by an admin at iasys.co.in has blocked your message.
You are not authorized to send this email. Please contact your Administrator.
The emails are sent from [email protected]. Please have your admin put in an exception for [email protected]. If you send us an email to [email protected], we can forward the bounce message from Office 365 if needed.