NI Instruments USB 6221 - Edge Counter

Hi!

i can get the edge counter value when start the motor manually. but when i tried to start the motor using a MATLAB programme, the edge counter value is always zero.

i try to use startForeground function and get the following error

The startForeground/startBackground methods are clocked operations. To use the session object in clocked mode with the counter input edge count channel 'ctr0', an external clock must be supplied. If the USB-6221 has an analog subsystem, add any analog input/output channel belonging this device (Dev1) to allow the session object to automatically configure itself to internally share this device's source clock.

i write the following matlab function: function counterValue = getCounterValue(ny)

daq.getVendors();%get vendor device details s = daq.createSession('ni');%create session using daq commant

s.addCounterInputChannel('Dev1', 'ctr0', 'EdgeCount'); %create channel fro inpurting the counter value s.resetCounters;%clear the counter channel s.Channels(1);%get information about the open channel data = s.startForeground; data counter = 1; while(counter < ny) counter = counter + 1; end counterValue = s.inputSingleScan; %store the counter value in return variable s.resetCounters; delete(s);%delete session

i hope there is someone that can help me about this.

Thanks a lot

Christos