Hello, A PCI-6601 may be able to control an SSR, but you must know the specs of the relay before you can be certain. The output voltage of the 6601's digital output line will be +5V with a source current of 4mA. This means that your relay must require no more than 4mA to turn on. Here is a link the 6601 User Manual. You can find these specifications on page A-1: http://digital.ni.com/manuals.nsf/websearch/DD0DBB6404BC139886256721007CF16D?OpenDocument&node=132100_US
If you think the board has enough current to power your relay, then you can make connections from the digital output lines of the board. These lines can be seen on page 4-2 of the manual. Regards, Bill B. Applications Engineer National Instruments
