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ba_aed104_8_e.doc
7.2
Adjustment and scaling
The commands described below serve for setting the factory characteristic as well as the user characteristic:
•
Commands for adjusting the transducer characteristic:
SZA
,
SFA
•
Commands for adjusting the user characteristic:
LDW
,
LWT
•
Scaling of the measured values:
NOV
Setting the characteristic
As delivered, the AED works initially with a factory characteristic
SZA / SFA
(range 0...2 mV/V). This
characteristic can be used for calibrating the the transducer characteristic. This characteristic should not be
changed. It has to be print ore stored to keep the data.
The user can adapt the AED characteristic to his requirements with the command pair LDW, LWT
(application or scale characteristic).
In the following, the balance of a measuring chain will be described with the balancing of a scale. This example
can also be used for other kinds of transducers.
Important Note
The characteristic commands
LDW, LWT
must be entered or executed in the sequence LDW , then LWT... The
input data are not computed until both parameters have been entered or measured in pairs The scaling must be
switched off when determining the characteristic (
NOV0
).
After the values for zeropoint and nominal value of the user characteristic have been measured or entered, the
range
LDW
Æ
LWT
(at
NOV
=0) is mapped to the following numerical ranges:
Output at nom. load (COF)
NOV=0
NOV>0
2 Byte binary
20000
NOV value
4 Byte binary
5120000
NOV value
ASCII
1000000
NOV value
For the 2-bytes binary output, the NOV value must be < 30000, otherwise the measured value is output with
overflow or underflow (7fff
H
or 8000
H
; H: Hexadecimal). With NOV30000, the overload range is only approx.
2700 digits.