Digital I/O

cancel
Showing results for 
Search instead for 
Did you mean: 

PCI-DIO-32HS start and stop trigger

I am using the PCI-DIO-32HS board to read signals from external source. There is a control signal CTRL from the external source to control the reading. Whenever the CTRL is low, the DIO board starts reading and whenever it is high, the board stops reading. I'm very confuse to select what pin on the DIO board for the control signal and how to implement it. Thanks for any help

PeterT
0 Kudos
Message 1 of 2
(3,761 Views)
Peter:
The PCI-DIO-32HS is capable of several different modes. One of them is pattern I/O where a clock (can be externally provided or internally generated) controls when each transfer occurs. You can use trigger with this mode. Start trigger is once you receive a rising edge on the ACK/STARTTRIG line then operation occurs.
From the way you described your application though, it sounds like you are using handshaking mode. In 2 way handshaking mode, both devices can stop and resume a transfer by deasserting their handshaking line. In 32HS, the REQ line is controlled by the external device and the ACK line is controlled by the 32HS device. You can programmatically set the handshaking lines to be active low or active high. Example: active low on both REQ and ACK me
aning that you are expecting the external device to drive the REQ line low whenever it is ready to transfer data and ACK line will be driven low when 32HS is ready. A transfer occurs when both parties are ready. So in your case, it is likely that you've send REQ to be active low. In that case, whenever REQ is high, transfer is paused, whenever REQ is low, transfer occurs (if the ACK is also ready)
Without knowing which mode of the 32HS you are using exactly, that's all the help I can offer. I would suggest you to look at the new user manual:
http://digital.ni.com/manuals.nsf/caba5d53e9b015a186256793004eebb7/ede443f5c700373a862569b90072d26f?OpenDocument
Which goes in details on each of the modes I discussed. The examples that comes with NIDAQ will also help you once you decide the appropriate mode. Hope this helps
Message 2 of 2
(3,761 Views)