Primary Question
Setup explained:
I am using a 7340 motion card, and I use modulus breakpoint to break down a distance of 35000 steps into 180 finite steps. What I do is find out the encoder counts to travel 35000 steps and divid that numer by 180 to find out the "Breakpoint modulus" and I use value of zero for breakpoint position. Please see attached picture for reference, the only thing different about my setup from the picture is I add a motion start before I start polling the breakpoint status, and I add a shift register in the while loop to keep track of total number of break points registered during the axis movement. One more thing I do define a breakpint window to combat jitter in the motion, bascially that prevents the breakpoints from firing at the same spot due to jitter if the breakpoints are too close to each other.
Problem faced:
I am confident in the correctness of my "breakpoin modulus" value, but I am not consistantly registering 180 breakpoints every run. Most of the time I get 180s, occasionally I get 160s and sometimes I get low 180s. I originally thought this has to do with the velocity of the movement of the axis and the rate which break point can reset (max 150hz). I usually run the velocity at 100000steps per sec, as an experiment I tried increasing and decreasing that value, but I did not see much if any difference in the resultant number of break points registered.
Secondary Question
Setup explained:
I have two axis of motion that require reading from one single DAQ card for force values, AI 0-4 for axis1 and AI5-9 for axis2. Depending on the situation user might be turning both axis at the same time. The motion card is connected with the DAQ card through a RTSI cable, and I like to use my break points(RTSI0) to create a sample clock for the DAQ card, basically telling it when to sample or read force values to correspond to the position of the axis.
Problem faced:
If I am running both axis at the same time how can I handshake with the DAQ card so I can correspond position with force for BOTH axis?
If you could provide any information that can potentially help me or even partial solve the puzzle, I will be grateful.
Joey Cao
CLD
