MSI-9008 CellScale Multiplexer
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User Guide
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M E A S U R E M E N T S Y S T E M S I N T E R N A T I O N A L
Introduction
The MSI-9008 Multiplexer is an input switching device that is digitally controlled by the MSI-9000 CellScale to switch
between eight possible input sources. The Multiplexer features an LED indicator designating which channel is currently
being switched to the output. The MSI-9000 CellScale controls the switching via three digital lines (Digital 0,1,2) on the
CellScale load cell connector. Excitation is passed from the control unit through the Multiplexer to each of the individual
input sources. At any one time, there are only two input sources being supplied power. All other inputs are turned off to
reduce power consumption.
The signal returned from the transducer (typically a load cell) is multiplexed or switched into a single channel input on the
CellScale (i.e. channel 1-x, 2-x, etc). This signal is then measured and processed according to the setup of the CellScale.
The following is an image of the circuit board. Note the spring-loaded terminal blocks for connecting the CellScale, load
cells, and additional Multiplexers.
Load Cell Connections
The MSI-9008 Multiplexer can control up to eight individual transducer inputs. These inputs can be taken directly from a
load cell or from junction/summing boxes combining multiple load cell signals. Devices such as load cells are connected
to the Multiplexer via four lines as summarized in the table below.
Load Cell Connections
Function
Description
+EXC
Positive Excitation
- EXC
Negative Excitation
+ SIG
Positive Signal
-SIG
Negative Signal
An additional shield connection is provided for terminating cable shields. For details regarding wire color codes, please
refer to the load cell manufacturer’s documentation.
