Ahlborn ALMEMO 204, Operating Instructions Manual, Page: 37 / 72

Two-point adjustment with Setpoint entry
14.3 Two-point adjustment with Setpoint entry
For universal error correction at any two points
the function menu
Two-point adjustment
is
provided. If the actual values at two points are
known, these can be entered together with the
associated setpoints. If not, two setpoint states
must be created and adjusted online. Usually,
for the first measuring point, a zero-point ad-
justment is performed; however, any other setpoint is equally possible. For the
second measuring point a gain adjustment is performed and all correction val-
ues are recalculated (s. 15.6).
Two-point adjustmen t (actual values are cleared)
1st Measuring point
Place the sensor in 1st status 0.0: 0.4 °C
(e.g. icy water, unpressurized, etc.), Actual val.1: -----
Select and enter setpoint 1
Setpoint1: 0.0
Adjust meas. value to setpoint 1 by pressing
<ADJ>
Measured value should now display setpoint 1
0.0: 0.0 °C
2nd Measuring point
Place the sensor in 2nd status
0.0: 99.45 °C
(e.g. boiling water, known weight, etc.) 2: -----
For the second meas. point enter setpoint 2
2: 100.0
Adjust gain in function 'setpoint 2' by pressing
<ADJ>
Measured value should now display setpoint 2 0.0: 100.0 °C
Correction value calculation:
Also enter known actual values in function Actual val.1: 0.4 2: 100.0
and calculate correction in function setpoint 2 by pressing
<ADJ>
If the sensor is locked, a confirmation request will appear asking
whether adjustment should indeed be performed.
14.4 Scaling
Sensors or transmitters with standardized signal
output will usually have to be scaled to be able
to display the physical variable. If two actual val-
ues and 2 setpoints have been entered, the
menu
SCALING
will, as in the previous chapter
(s. 14.3), perform the task of calculating the
scaling values, base value and factor (s. 15.7).
The desired units, the decimal point position,
and the number of decimal places must also be entered.
Calculating the scaling values
After entering all the necessary parameters the scaling values
are calculated in function 'setpoint 2' by pressing
< ADJ >
ALMEMO ® 204 37
TWO-POINT ADJUSTMENT:
0.0: 1.67 °C Temperature
Actual val.1: ----- 2: ------
Setpoint 1: 0.00 2: 100.00
Zero-point: ------ °C
Gain: ------
ADJ ESC F FCT

SCALING: 0.1: 4.67 mA
Actual val.1: 04.000 2:20.000
Decimal point: 1 Unit: °C
Setpoint 1: -100.0 2: 400.0
Gain: ------
Base: 720.0 °C
Factor: 0.3125 E2
ADJ ESC F ON