# LabJack U6 - Had this on hand from past projects on beam on target Fusor control and instrumentation - Link to product page: - https://labjack.com/products/u6 - Relevant specs for using this for data logging on [[6320F Bringup Log]] - 14 analog inputs - Range +-10V - Selectable gain x1, x10, and x100 - Can do single ended or differential in even/odd pairs - 16 bit at max speed (20us conversion) - Increases to 18 bits at slower speeds ## Configuring for low noise - Higher resolution = longer sampling times = less noise - The U6 can have a resolution setting in LJLog between 0-12 - See https://labjack.com/pages/support?doc=%2Fdatasheets%2Fu6-datasheet%2Fappendix-b-noise-and-resolution-tables-u6-datasheet%2F for tables giving resolution and noise specs - Still seamed to be getting to much noise. Then I realized that there was no ground connection between the U6 and the microscope. Adding a ground between the GND test point on the Vacuum Board and the GND terminal on the U6 drastically reduced noise. - ![[IMG_1337.jpg|lg]] ## Configuring the software - Plugged in LabJack over USB - Start software - ![[Pasted image 20221230140028.png|lg]] - Selected Open the First Available Device - ![[Pasted image 20221230140128.png|lg]] - Chose "Use Default Configuration" - ![[Pasted image 20221230140237.png|lg]] - What software looks like after it has seen the labjack - Ok I want to short some pins together on the LabJack to see if I can make the color line change. - ![[Pasted image 20221230142049.png|lg]] - ![[IMG_1329.jpeg|lg]] - Physical configuration with AIN3 connected to GND and AIN1 connected to VS ### +Ch and -Ch - Each channel in LJLog gets where it references positive and negative set separately. - ![[Pasted image 20221230140855.png]] - For example, here channel 0 is looking at analog in 0 and comparing it with the internal ground (channel 199 is internal ground) - There are several special analog input channel numbers that allow you to read wrt other functions of the LabJack. Section 3.2.1 of the U6 user guide has details on what these channels are. - [[Special Channel Numbers LabJack U6]] ### Scaling Equations **Scaling Equations:** Should be something like `y=a`, where `y` is the scaled output and `a` is the input voltage of the 1st row.  `b` through `p` would be the input voltage of the rest of the rows. Everything after `//` is ignored, so use for comments.  A few examples: - `y=c // Scaled value equal to raw value from 3rd row` - `y=100*c // EI-1034/LM34 voltage to deg F` - `y=c-273.15 // deg K to deg C` - `y=((c-273.15)*9/5)+32 // deg K to deg F` - `y=TCVoltsToTemp[K:c:a] // Type K, t/c voltage from 3rd row, CJ temp from 1st row` More info: https://labjack.com/pages/support?doc=/software-driver/labjack-applications/ljlogstream-scaling-equations/ ### Gain/amplifier settings Are in this dropdown: ![[IMG_2958.png|grid]] LJ_rgBIPP01V = the +-.01V range LJ_rgBIP10V = the standard +- 10V range ## Hardware configuration ### Scaling up A [[Op amp circuits - Non inverting amplifier|non inverting]] op amp should be used There is one inside the U6, or add your own ![[Pasted image 20221230144343.png]] $V_{out} = V_{in}*(1+\frac{R2}{R1})$ 100 KOhms is typical for R2 ### Scaling down #### [[Voltage divider]] ![[Pasted image 20221230143114.png]] $V_{out} = V_{in}*\frac{R2}{R1+R2}$ If two 1 kOhm resistors are used, the scaling factor is 2 so the input range is scaled to +- 20V #### Voltage divider with [[Op amp circuits - Buffer|buffer]] If Big Resistors are used, a buffer should be added because otherwise the signal current is very low ![[Pasted image 20221230143401.png]] The LT1490A is recommended Op amps can be powered by the +-Vm supplies (+-12) on the U6 For 0-5V applications (the op amp is powered from Vs and GND) the OPA344 is recommended ### Current measurement Use a current shunt (LabJack sells an extension for this) ![[Pasted image 20221230145542.png]] A typical shunt resistance is 240 Ohms for a 4-20 mA signal The shunt is specified based on: - Maximum current - Tolerable voltage drop ## Software LabJack releases a few basic data logging applications that work out of the box. - LJLogUD for < 100 Hz applications - ![[CleanShot 2022-12-30 at [email protected]|lg]] - LJStreamUD for > 100 Hz applications ## Pinout ![[CleanShot 2023-02-18 at [email protected]]] ## Architecture ![[CleanShot 2022-12-30 at [email protected]|lg]] ## Datasheet ![[LabJack-U6-Datasheet.pdf]]