Overflow Monitoring
(Original Document)
About us
Introduction
The TSX AEY 420 module allows you to select between 6 voltage or current ranges for each input.
Whichever range is selected, the module always checks for overflow to verify that the measurement falls between a lower and an upper threshold.
This monitoring is optional.
The module typically tolerates a 5% overflow of the positive current range covered.
Measurement Areas
The measurement range is divided into 5 areas: 
Nominal Area
Measurement range matching the chosen range. 
Upper Tolerance Area
Varies between the values included between the maximum value for the range (for instance: +10 V for the +/-10 V range) and the upper threshold. 
Lower Tolerance Area
Varies between the values included between the minimum value for the range (for instance: -10 V for the +/-10 V range) and the lower threshold. 
Overflow Area
Area located beyond the upper threshold. 
Underflow Area
Area located below the lower threshold.
Overflow Flags
In over/underflow areas, there is a risk of saturating the measurement device. In order to counter this risk through the user program, detected error bits have been prepared:
Bit Name
Flag (when = 1)
%IWr.m.c.1.5
The value being read falls within the lower tolerance area.
%IWr.m.c.1.6
The value being read falls within the upper tolerance area.
%IWr.m.c.2.1
If over/underflow control is required, this bit indicates that the current value falls within one of the 2 unauthorized ranges:
  • %MWr.m.c.2.14 denotes an underflow,
  • %MWr.m.c.2.15 denotes an overflow.
%Ir.m.c.ERR
Detected channel fault.
NOTE: During an under/overflow, peaks in the measured value are suppressed so that the offending value conforms to the appropriate threshold.
Values for Under/Overflow Thresholds
Values for those thresholds are configurable independently from one another. They may assume integer values between the following limits:
Range
Lower Tolerance Area
Upper Tolerance Area
Default Value
Maximum Value
Min. Value
Default Value
Min. Value
Maximum Value
Bipolar
+/-10V
-0.125 x /2
0
- 0.25 x /2
0.125 x /2
0
0.25 x /2
Unipolar
0...10V, 0...5V, 1...5V, 0...20 mA, 4...20 mA
-0.125 x
0
-0.25 x
0.125 x
0
0.25 x
Normalized
-1250
0
-2500
1250
0
2500
User bipolar
+/-10V
-0.125 x /2
0
-0.25 x /2
0.125 x /2
0
0.25 x /2
User unipolar
0...10V, 0...5V, 1...5V, 0...20 mA, 4...20 mA
-0.125 x
0
-0.25 x
0.125 x
0
0.25 x
Legend:
Range upper value - Range lower value