Ahlborn ALMEMO 204, Operating Instructions Manual

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5. Introduction
Conversion between °C (Centigrade) and °F (Fahrenheit) is performed auto-
matically.
Measured value designation
To help identify sensors an alphanumeric designation is also provided (V5 10
characters, D7 up to 20 characters). This designation appears in each mea-
sured value display, in the printout, or on the computer screenm.
Correction of measured values
The measured value on each measuring channel can be corrected both in
terms of zero-point and gain; this means that even sensors usually requiring
initial adjustment (e.g. expansion, force, pH) can be interchanged freely. Zero-
point correction and, partly at least, gain adjustment can be performed at the
touch of a button. Sensors with multi-point calibration can also be connected.
(see Manual 6.3.13).
Scaling
The corrected measured value on each measuring channel can also be further
scaled in terms of zero-point and gain based on the base value and factor. The
decimal point position can be set by means of the 'Exponent' function. Scaling
values can be calculated automatically by setting to zero and entering the nomi-
nal setpoint or via the scaling menu.
Limit values and alarm
Per measuring channel two limit values can be set (one maximum and one
minimum). In the event of one of these limit values being infringed an alarm
signal is output and relay output modules actuate the associated alarm con-
tacts; these can be allocated individually to specific limit values. Hysteresis is
set by default to 10 digits; however, this can be adjusted to any value between
0 and 99 digits.
Sensor locking
All sensor data stored in the EEPROM in the plug can be protected - by means
of a graduated locking function - against undesired access.
5.1.2 Measuring operation
For standard sensors up to four measuring channels are available; i.e. it is thus
also possible to evaluate double sensors, individually scaled sensors, and sen-
sors with function channels. All activated standard measuring channels are
scanned continuously at the sampling rate and the data acquired is shown in
the display. A D7 sensor has up to 10 channels and a sampling rate corre-
sponding to its own individual measuring speed; this sampling rate can be ap-
plied individually over the new scan cycle.
Measured values
The display can show measured values either (in various menus, some user-
configurable) in two font sizes - or (in one of the user menus) in the form of a
bar chart. Measured values are acquired automatically with auto-zero and self-
calibration; however, they can also be corrected and scaled as and whenever
required. With most sensors a sensor breakage is detected automatically.
12 ALMEMO ® 204