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Hello, I have a question regarding the communication protocol and physical layer of how to connect the motors of a robotic arm.
I have 4 servomotors, Brushless. I need to select a motor drive for each one. The motors are: M1 shoulder- M2 elbow- M3 wrist- M4 thumb
in a daisy chain. I've seen...
Thank you very much for your reply. I know that there is a braid as you very well mentioned, but the truth is I wouldn't imagine it can cause such an issue. I will take this into consideration. I will post layout of the pcb when I have it available.
You made a very good point, I was also doubtful regarding the connectors. We have only four channels, Vdd, GND, Data+ , Data-. There is no shielding. It is true that USB standard cable has two more shields, but I think that for the 2.0 that we use we don't need it. I found that these additional...
Thank you for your reply. When you say bad USB wiring what do you mean? I don't see any issue in that on my pcb. And if it's the case, how do I prove it?
Update: Its impossible to desolder the components, they're so well soldered and so close to each other that I am afraid I will damage them...
Thank you for your reply. I see, well I hoped it was related, because other than that, which I hoped it was, I can't identify any other cause. I have two pcbs that are identical ! How is it possible that they behave differently? the issue is always on one of the cameras that uses 1.5 m long...
Re: why longer cable not able to stream form camera
Thank you very much. The cable is usb 2.0 standard: has 4 channels, as the common usb 2.0 (Vcc =5V, data +, data -, gnd). The cable of each camera connects to a 4 pin connector. The channels of the connector get the usb channels through a usb...
why longer cable not able to stream form camera
Hello,
This is my problem: I have two connectors on a pcb to which I connect two cameras. One of them is 5 times longer than the other (long is aproximately 1.5 meters). Unfortunately I can't reduce the length of the cable, it is vital. The...
Thank you for your reply. To clear things up: The pcb is powered with 12 V. There is also the usb port that provides 5V.
Yes, I measured 20V on the input (vcc pin of the usb port on the pcb at the input). At the attachment vcc is the yellow channel. I also measure the spike on the Vout of the...
Ok thank you for your reply. I will remove then the components and I will try to measure them.
How I measured the spike: The input of the pcb that connects to the usb port has 4 pins: vdd, Data-, Data+, GND. On the Vdd I measure the spike. Also see in attached the image the blue is the vout...
Hello, I tried to simulate the behavior I described above but I can't. LT-Spice shows that the voltage of the output never exceeds 3.3 V. I selected DC sweep.
However the real response of the voltage is this: Am I doing anything wrong?
thank you !
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Thank you very much for your reply. What I don't understand is why some capacitors on the pcb show the correct value, while others show nothing. How is that possible? You see there is an issue to remove all of them. We talk about 60 caps at least here...And I don't trust I...
Hello, I have the following question please. How can I measure the capacitor on a pcb? I have a keysight digital multimeter and I select the capacitance symbol. However, for some capacitors, the indication seems blank. I see mF and it seems like it's waiting for ever to show a value. I tried...
Here's my update, please comment on the following. There is a voltage regulator in the schematics: https://www.ti.com/lit/ds/symlink/lm1086.pdf
It seems that in normal operation, Vin= 5V, Vout =3.3V and Vadj =2 V. R3 = 120 Ohms and R4= 200 Ohms. However:
If I try to plug the power supply of...
Guys, I measured the current consumption at the USB3 port, it's 149 mA, which is a lot below of the max consumption of a USB3 port. When I touch the pins with the Amper-meter, the camera connection is lost, it resets. Is that normal?
Hello, thank you for your reply. Of course I have changed cables, usb cables, pcbs, instruments but it always happens. My question is how to approach more specifically and what kind of phenomena you think might occur here.
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