5. Introduction
Measuring ranges
Appropriate measuring ranges are available for all sensors with a non-linear
characteristic, e.g. 7 thermocouple types, NTC probes, and flow transducers
(rotating vanes, thermoanemometers). For humidity sensors additional function
channels are available for calculating humidity variables such as dew point,
mixture ratio, vapor pressure, and enthalpy. Measured values from other sen-
sors can also be acquired using the voltage and current ranges with individual
scaling in the connector. Existing sensors can also be used - so long as the ap-
propriate ALMEMO
®
connector is connected via its screw terminals. For digital
input signals, frequencies, and pulses, adapter connectors are available with
an integrated microcontroller. It is thus possible to connect numerous sensor
types to any ALMEMO
®
measuring instrument and to change sensors without
the need for any extra settings.
Function channels
Maximum, minimum, and average values of certain measuring points can be
programmed as function channels and can be processed and printed like nor-
mal measuring points.
Units
The 2-character units display can be adapted for each measuring channel so
that both the display and the printout always indicate the correct units, e.g.
when a transmitter is connected. Conversion between °C (Centigrade) and °F
(Fahrenheit) is performed automatically.
Measured value designation
Each sensor is identified by means of a 10-character alphanumeric name. This
name is entered via the interface and will appear in the printout or on the com-
puter display.
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) can be freely interchanged. 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
decimal point position can be set by means of the exponent function.
Limit values and alarm
Per measuring channel two limit values can be set (1 maximum and 1 mini-
mum). In the event of one of these limit values being exceeded relay output
modules actuate the associated alarm contacts; these can be allocated individ-
ually to specific limit values. Hysteresis is set by default to 10 digits but this can
be adjusted to any number between 0 and 99. The exceeding of a limit value
can also be used to start or stop measured value recording automatically.
10 ALMEMO
®
2450-1
