Messages

1

DAQ Software/Firmware / Re: problem changing excitation LED power

« on: December 03, 2016, 09:31:22 PM »

Hi Daniel, thanks again, it seems indeed to be an issue with too little voltage being sent from the CMOS to the LED: it is still not fully clear what is going on, I tried the following:
1) use long mouser cable: measure 3.4V at sig/gnd on CMOS PCB, 2.3V on LED output CMOS, 3rd top LED on the DAQ PCB is on > cannot control LED intensity
2) short RG58 50Ohm coaxial cable 4.8V at sig/gnd on CMOS PCB, 2.6V to LED, 3rd LED is not on > cannot connect to the scope

Unfortunately, I now started to get again "msCam frame retrieve error!" with setup 1 (using 2 different DAQ boards and 2 different CMOS PCBs that previously worked), even though all three LEDs are on, and the same voltages are measured (3.4V at sig/gnd on CMOS PCB, 2.3VLED on LED output CMOS). I will try to find another USB3.0 port (so far this was the only USB3.0 port on which I got the boards to work) but if you have any other ideas what to check let me know.

2

DAQ Software/Firmware / Re: problem changing excitation LED power

« on: December 02, 2016, 03:29:23 PM »

I'm using the thin Mouser coaxial cable (42AWG, 50 OHM, 538-50MCX-37), cable length is about 150cm/5ft. The voltage measured at the solder joint of the CMOS PCB with the coaxial cable is 2.3V and the voltage at the solder join of the LED PCB with the coaxial cable is also 2.3V (when I measure the voltage at the SMA connecting the DAQ PCB to the coaxial cable it is 4.7V). I have attached a picture of the top and bottom. I will next try to find a  different type of thin coaxial cable from maybe digikey (Cooner wire is harder to get hold of here). If you have any other suggestions what could be the problem that would be great, thanks!

Here are the pics of the CMOS:
https://dl.dropboxusercontent.com/u/21675823/CMOS_back.JPG
https://dl.dropboxusercontent.com/u/21675823/CMOS_front.JPG

3

DAQ Software/Firmware / Re: problem changing excitation LED power

« on: December 01, 2016, 07:21:26 PM »

Hi Daniel, many thanks for your comments. To answer your questions:
- changing exposure or gain does indeed have the expected effect on the video stream
- the LED is not damaged (I'm testing this with an LED that still has the silicone and I am able to increase or dim LED intensity using a separate power supply with variable resistor)
- I also think it is correctly wired to the CMOS otherwise I think it would not light up at all?
- When I connect a multimeter to the CMOS output without any LED, the excitation LED slider in the GUI increases the current from 0.04mA at 0 to 20mA at 20 and 40mA at 40%. However, when I directly connect the cathode and anode of the LED, the current is about .1 mA and does not change when I change the slider... When I connect the CMOS output to the LED board with the soldered LED, the current is also ~0.1 mA and I am not able to change it by moving the GUI slider. Should I expect any difference between using the LED directly vs the LED on the LED board? If you have any other suggestion what is going on that is very much appreciated! Best, Jasper

4

DAQ Software/Firmware / Re: problem changing excitation LED power

« on: December 01, 2016, 01:25:12 PM »

Hi Daniel,

Thanks for your suggestion: I am indeed using version 3.2, but I did already solder the solder-jumper on the bottom of the PCB (just double checked with two different CMOS PCBs; they both have the same issue but both have the jumper connected).

Is there perhaps a quick way to probe whether the solder-jumper is working as it should on the other side of the board?
Or is there any other possible cause? Is the LED supposed to turn on the moment you connect the DAQ PCB to the USB?

Thanks!