90 Spyder3 SG-34 GigE Vision Color Manual
03-032-20124-00 Teledyne DALSA
How the Lookup Table Works
The Lookup Table has 8 inputs (I0 - I7) capable of two states each (true, false). Thus, the outputs have a total
number of 256 input combinations. The result of each combination can be 1 or 0.
When you modify the equations in the Lookup Table, the controller calculates the results of all 256 input
combinations and stores the result of each output as a 256-bit lookup table (hence the name). There are 18
outputs (Q0 - Q17), so the controller calculates 18 different lookup tables.
The controller then passes the resulting 18 lookup tables to the IP Engine. Knowing the value of the 8 inputs,
the PLC needs only look up the value of the resulting output (for each output), rather than calculate it. Thus,
the Lookup Table can achieve a propagation delay of only one system clock cycle (30 ns), regardless of the
complexity or number of Boolean expressions.
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