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Connecting Signals
4-17
In Scheme 1, you connect the trigger/gate inputs of the three boards
together and supply the trigger or gate input. A/D conversions on each
board start 400 ±100ns from the active edge of the trigger input. All
conversions start within 100 ±100ns of each other from board to board.
When using scheme 1, you can use the onboard pacer clock or an external
pacer clock.
In Scheme 2, you can start conversions in either of two ways: by a
hardware trigger/gate input or by software. The board connections are in a
master/slave relationship; board 0 is the master, and boards 1 and 2 are
the slaves.
If you use a software enable for board 0 of scheme 2, the board 0 pacer
clock starts and triggers conversions in the slave boards. However, board
0 conversions do not begin until after conversions begin in the the slave
boards. The delay of board 0 conversions is caused by a protection feature
built into the register that creates software-triggered conversions; the
function of the protection feature is to prevent false conversions.
If you use a hardware trigger for board 0 of scheme 2, board 0 triggers
conversions in all three boards immediately. Note that TGOUT is an
active, high-going signal. Therefore, you must program the slave-board
TGIN inputs for a positive-going trigger or gate.
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