Note: Boards Rev A1 have a different configuration table that can be found in Appendix A.
The default configuration is IRQ7 for COM3, IRQ10 for COM4 and IRQ5 for A/D.
The example in Figure 16 show the jumper settings for configuring COM4 for IRQ3, COM3 for IRQ6 and ADC for
IRQ5.
Analog I/O Single-ended/Differential Configuration (JP4)
The input channels on Poseidon can be configured as 32 single-ended, 16 differential, or 16 single-ended plus 8
differential. Four different configurations are possible for the Data Acquisition (Analog I/O) connector, CN13.
A single-ended input is a single-wire input, plus ground, that is measured with reference to the board’s analog
ground. For accurate measurement, the board’s ground must be at the same potential as the source signal’s ground.
Usually this is accomplished by connecting the two grounds together at some point.
A differential input is a two-wire input, plus ground, that is measured by subtracting the low input from the high
input. This type of connection offers two advantages.
It allows for greater noise immunity, because the noise, which is present in equal amounts and equal phase on both
the high and low inputs, is subtracted out when the low input is subtracted from the high input.
It allows for the signal to float away from ground. Normally the ground of the signal source is still connected to the
ground on the A/D board in order to keep the signal from straying out of the common mode range of the A/D
board’s input circuitry.
To configure the input channels, set the pin pairs in jumper block JP4 according to the table, below.
Note: For safety reasons, do not modify JP4 while the board is powered on.
Connector Pin Configuration
1-2
3-4
5-6
7-8
9-10 11-12
Inputs 0-31, single-ended (default)
In
In
Out
Out
Out
Out
Inputs 0-15, differential
Out
Out
In
In
In
In
Inputs 0-7, differential
Inputs 8-15, single-ended
Inputs 24-31, single-ended
Out
In
In
Out
In
Out
Inputs 0-7, single-ended
Inputs 8-15, differential
Inputs 16-23, single-ended
In
Out
Out
In
Out
In
For example, Figure 17 shows the JP4 jumper settings to configure CN13 pins 0-15 for differential mode.
Diamond Systems Corporation
Poseidon User Manual
Page 40
Figure 16: IRQ Selection Example
