MSI-3750 Digital Weight Indicator
◆
User Guide
Page 129
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
scale will not weigh. This is equivalent to shorting out the signal
leads.
3)
SW1 and SW2 switch in offsetting resistors. The offset can be
overcome with combinations of SW1 and SW2. Use the follow-
ing table for guidance while watching the bargraph in the cali-
brate zero step. Note in the table that “-50%” indicates that the
offset will be reduced by 50%. Therefore use -50% for scales that
have positive offset. The percentage is approximate and depends
on the actual mV/V of the load cell.
~% Offset
SW1
SW2
SW3
SW4
-50%
Off
On
Off
On
-100%
On
Off
Off
On
-150%
On
On
Off
On
+50%
Off
On
On
Off
+100%
On
Off
On
Off
+150%
On
On
On
Off
No Change
X
X
Off
Off
x= don’t care
4)
Once the offset has been overcome and the bargraph at zero load
shows a reading from 10% to 60%, proceed at step 8 of the Init
Cal Procedure.
RAW COUNTS
The 3750 uses a 20 bit A/D converter to measure and convert the output from
load cells. It is sometimes useful see the “Raw Counts” of the A/D to ensure
system functionality. A very useful application of Raw Counts is in balancing
multiple load cells with summing boxes. Raw counts are displayed divided by 10
so that 50000 raw counts displayed is equal to 500000 internal counts.
The following procedure will erase any calibrations and Scale setups.
Following the use of Raw Counts, the user must perform an “INIT
CAL” procedure. If you wish to use Raw Counts, do it before calibrat-
ing the system.
CAUTION
Displaying Raw A/D Counts
1)
First follow the “RESET CAL” procedure.
2)
Next follow the “INIT CAL” procedure completing all the steps
up to and including step 6. Be sure you set the appropriate gain
for your load cell(s).
3)
Now instead of Zeroing the Scale, push the EXIT key twice. The
Summary of Contents for MSI-3750
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