Serial

[AleksF]

Hi Centerbolt and everybody in the forum.

Well, at least the interface is running, and it works perfectly. All the hardware as I supposed was fine, the program in a big sense is right too, but there´s a little tiny mistake that provoke that the entire system doesn´t works as I expected. The problem was that I didn´t wire the TERMINATION CHARACTER ENABLE so, because the default state is TRUE, when the system recognizes this character ends the reception, so the solution was WIRE A BOOLEAN CONTROL AND TURN IT TO FALSE. When I did this all begins to works.

I can´t identify the problem before because the analog inputs of the system in much cases were connected to voltages greater than 0 V. So the default termination character is a 0xA, when the voltage goes down enough, the reception is terminated because the detection of this character in the stream of RS232 data.

So, my advice is: CHECK ALL THE UNWIRED CONNECTIONS and CHECK THE DEFAULT VALUES of the blocks that you´re using in your VIs.

Thanks to all for the tips and suggestions, specially Centerbolt for dedicate so much time to my problem.

[dicaranx]

Hi AleskF, I've read in detail your project to acquire analog signals and to control servomotors with LabView and a PIC16F877. I am actually doing the same project but I have had troubles and I don´t know if it is the electronic circuits or the software. I started trying with matlab, but when a plot the data from the analog signals there are points where the values are not consistent with the expected ones, I thought it was my routine in the PIC, and I try to made te conversion with an ADC 0809 converter, but i still have the problem.

On other hand, I am getting the same problem that you had; sometimes the data acquisition is stoped when I'm acquiring and controlling servos. On this way after reading your messages on the forum, I decide to try with LabView but the problem is the same. Right now I am using the USB 6008 data acquisition card from NI to check how is the signal, but it´s ok, the only problem is that it seems to be slower the response to the servo routine using rs232.

I am new in this stuff so I will realy aprecciate if you could help me with the electronic based on the PIC just in the A/D conversion because the servo routine works fine for me, and beacuse the USB 6008 card is from the University lab, and I want to develop my own data acquisition system.

Thanks a lot.