Ahlborn ALMEMO 2590-2A Operating Instructions Manual page 12

5. Introduction
programming via the keypad or via the interface.
Measuring ranges
Appropriate measuring ranges are available for all sensors with a non-linear
characteristic, e.g. 10 thermocouple types, NTC and PT100 probes, infrared
sensors, and flow transducers (rotating vanes, thermoanemometers, Pitot
tubes). For humidity sensors additional function channels are available for cal-
culating humidity variables such as dew point, mixture ratio, vapor pressure, and
enthalpy. Even complex chemical sensors are supported. Measured values from
other sensors can also be acquired using the voltage, current, and resistance
ranges with individual scaling in the connector. Existing sensors can also be
used - so long as the appropriate ALMEMO ® connector is connected via its
screw terminals. For digital input signals, frequencies, and pulses, adapter con-
nectors are available with an integrated microcontroller. It is thus possible to
connect virtually any sensor to any ALMEMO ® measuring instrument and to
change sensors without the need for any extra settings.
Function channels
Maximum, minimum, average, and differential values from certain measuring
points can be programmed as function channels, also internal channels, and
can be processed out like normal measuring points. There are also function
channels available for special measuring tasks, e.g. to determine the tempera-
ture coefficient Q/T and wet bulb globe temperature.
Units
The 2-character units display can be adapted for each measuring channel so
that the display always indicates the correct units, e.g. when a transmitter is
connected. Conversion between °C (Centigrade) and °F (Fahrenheit) is per-
formed automatically.
Measured value designation
Each sensor is identified by means of a 10-character alphanumeric name. It is
entered via the keypad or the interface and appears in the display, or on the
computer screen.
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 ad-
justment (e.g. expansion, force, pH) can be freely interchanged. Zero-point cor-
rection 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
Section 6.3.13).
Scaling
The corrected measured value on each measuring channel can also be further
scaled in terms of zero-point and gain - using the base value and factor. The dec-
imal point position can be set by means of the exponent function. The scaling
values can be calculated automatically by setting to zero and entering the nominal
setpoint or via the scaling menu.
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