The way that you can trigger all the channels on your cards is going to depend on a few things:
1. Are you using PCI-5102 devices or PXI-5102 devices?
For PCI devices, if providing an external hardware trigger you can just split the external signal and wire to all of the devices' TRIG lines (making sure to have the trigger signal cables close to the same length to avoid skew). If you want to trigger them internally, you will need RTSI cables connected between each device's RTSI connector. The RTSI connector allows you to share various internal timing and trigger signals. You could also wire one device with an external trigger and then share that trigger internally to the other devices via the RTSI connections.
For PXI devices, if providing an external hardware trigger you can just split the
external signal and wire to all of the devices' TRIG lines (making sure
to have the trigger signal cables close to the same length to avoid skew).
If you want to trigger them internally, all of the necessary timing and triggering connections are taken care of in the PXI chassis backplane. You could also wire one device with an external trigger and then
share that trigger internally to the other devices via the RTSI
connections.
2. What development environment are you using?
There are a number of shipping examples available for the various development environments that the NI-SCOPE driver can provide APIs for. I will assume for the moment that you are using LabVIEW based upon previous forum posts you have had. If you search in the NI Example Finder (Help>>Find Examples) the NI-SCOPE examples are located in Hardware Input and Output>>Modular Instruments>>NI-SCOPE. For a single board, the niScope EX Configured Acquisition.vi can show you how to implement a hardware trigger. For multiple boards, the synchronization examples are a good place to start, particularly the example niScope EX 5102 Synchronization.vi.
3. Do you just want to trigger the devices so that they simultaneously start, or do you want them to be truly synchronized?
For just simultaneous start, the devices will share a common start trigger for their acquisitions. For true synchronization, both the start trigger as well as a reference or sample clock will have to be shared among the devices. The synchronization example I have already referenced is a good place to start for both, but if you just need simultaneous starting then you will just need to strip out the code involved in routing the clock signals.
