Omega Engineering OMB-DBK-34A, User Manual

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Channel and Card Address Selection
The lower and upper channels on the DBK16 are multiplexed into one of
the channels (0 to 15). The base channel (that the DBK16 is multiplexed
into) is set by the shunt jumper on the16×2 header designated
JP1 (see
previous figure, DBK16 Board Layout).
Each base channel can have up to 16 expansion channels multiplexed into
it. Since the DBK16 represents two expansion channels, eight DBK16
cards can be multiplexed into each base channel. To distinguish channels,
there is a card address bank of three switches on each DBK16. These
switches are binary-weighted with eight possibilities (0-7).
Base
Channel
First Expansion
Channel
Number (N)
0 16
1 32
2 48
3 64
4 80
5 96
6 112
7 128
8 144
9 160
10 176
11 192
12 208
13 224
14 240
15 256
DIP Switch Setting Card Channels (n)
C B A Upper Lower
Open Open Open 1 0
Open Open Closed 3 2
Open Closed Open 5 4
Open Closed Closed 7 6
Closed Open Open 9 8
Closed Open Closed 11 10
Closed Closed Open 13 12
Closed Closed Closed 15 14
The switch settings are: open = 0, closed = 1 (enabled). The weights (when closed) are: A = 1, B = 2, C = 4 .
The table above shows the switch settings. The table to the right lists card channels (n) with respect to the base
channel.
Since the LogBook or the Daq device has sixteen base channels, up to 128 DBK16s can be used, providing a
maximum of 256 channels. To keep track of all base and expansion channels, the base channels are designated
0 to 15 and the expansion channels are designated 16 to 271. Channel 16 is the first channel on the first
expansion board (lower channel on card address 0 with JP1 set to CH0). Channel 271 is the last channel on the
last expansion board (upper channel on card address 7 with JP1 set to CH15).
To calculate the actual input channel, use the above tables and add the applicable “N” and “n.” The result is the
expansion channel number. This number is needed when writing a program to read from that particular
channel. For more information on multiplexing, refer to the
Signal Management chapter.
DBK16, pg. 8
879895
DBK Option Cards and Modules