Hi,
I am new to data acquisition and I have one very simple doubt. I am trying to write a simple test program using VB 5 and my very simple test board. The program is meant to read 100 times the content of port 0 (A+B) and plot it in a graph. I am using a simple home made board with a few switches on the board to generate my signal and the REQ1 signal.
From what I have read on the manuals and here all I would need to know is to have REQ1 high to trigger the transfer. I am using DAQ legacy drivers because I have other applications here that use that driver instead of the new one. Once I understand how this works I can change all applications to use the newer driver.
My code (removed error detection parts):
status = DIG_Grp_Config(deviceNumber, 1, 2, 0, 0) --> set port 0 as a 16 bits port
status = DIG_Grp_Mode(deviceNumber, 1, 3, 0, 0, 0, 0) --> set burts handshake w/ active high req
status = Set_DAQ_Device_Info(deviceNumber, ND_CLOCK_REVERSE_MODE_GR1, ND_OFF) --> i think this is not necessary but in the final application the DIO card is supposed to generate the clock signal
status = DIG_Block_In(deviceNumber, 1, StepBuffer%(0), TotalSamples&) --> start the data input
While ((remaining_points& <> 0) And (status% = 0)) 'While there are items to acquire and no error --> monitor the end of the process
status = DIG_Block_Check(deviceNumber, 1, remaining_points&)
DoEvents 'Return control to the host system
Wend
status = DIG_Block_Clear(deviceNumber, 1) --> terminate transfer
status = DIG_Grp_Config(deviceNumber, 1, 0, 0, 0) --> DIO back to normal
status = NIDAQPlotWaveform(StepBuffer(0), 100, WFM_DATA_I16) -- table plot
The problem is that the program locks and waits for the req for a long time.
My REQ1 input is a pull up resistor connected to pin 1 in my switch and to DIO's +5V output. The other end of the switch goes to ground. When I measure what is supposed to be my active high REQ1 (>= 2.7V) I get only 0.9V. Am i missing something on the hw side? Can I implement the REQ signal this way or is there any other better way? I want to try it with my simple board (that has no expensive parts) first before connecting it to the target system.
I would appreciate any help and I can provide as much information as required to answer my question.
Thanks in advance,
