DI-149 counter channel

DI-149 counter channel

I'm programming in Python 3.5 on Linux using the di149 protocol. I'm having problems with the counter channel. When using a PWM at 50% duty cycle It undercounts when the srate is set less than 250 Hz. For example: If I have signal set to 100Hz and srate set to the min of 11.4 Hz it will count to 3 over 1 second. When I increase the srate to 250 Hz the count will increase to 100. When I use a hall effect sensor this low count problem becomes worse. Both the PWM and hall effect sensor work as expected on the rate channel. If I use WinDaq on a Windows 10 machine the counter appears to function properly with the same setup. So far I've been using asc and float output. If you have any suggestions for me they would be appreciated, i've tried everything I can think of.