Connecting The Transducers; Transducers; Measuring Inputs And Additional Channels - Ahlborn ALMEMO 5690-1M Operating Instructions Manual

7.

CONNECTING THE TRANSDUCERS

Virtually any ALMEMO ® sensor can be connected to the input sockets on AL-
MEMO ® modules types (2) and (3). To connect your own existing sensors you
simply need the appropriate ALMEMO ® connector. Other compact modules
are described below.

7.1 Transducers

The ALMEMO ® Manual includes detailed descriptions of the comprehensive
ALMEMO ® range of sensors (see Manual Ch 3) and instructions for connecting
your own existing sensors to ALMEMO ® instruments (see Manual Ch 4). All
standard sensors with an ALMEMO ® connector usually have the measuring
range and units already programmed and can thus be connected to any input
socket without further adjustment. A mechanical coding system ensures that
sensor and output modules can only be connected to the correct sockets. All
ALMEMO ® connectors incorporate two snap-lock levers; these snap into posi-
tion as soon as the connector is inserted into the socket, thus preventing unin-
tended disconnection if the cable is accidentally pulled. To withdraw the con-
nector, both these levers must be pressed in at the sides.

7.2 Measuring inputs and additional channels

Measuring circuit board MM-A9 has 9 input sockets (2c) to which initially
measuring channels M0 to M8 are allocated. However, ALMEMO ® sensors
can, if required, provide up to 4 channels with 9 input sockets each so that
altogether 36 channels are available. The additional channels can be used in
particular for humidity sensors with four measuring variables (temperature /
humidity / dew point / mixture ratio) or for function channels. Each sensor can
if necessary be programmed with several measuring ranges or scaling set-
tings; and two or three sensors, if pin assignment so permits, can be combined
in a single connector (e.g. rH / Ntc, mV / V, mA / V, etc.). The additional meas-
uring channel numbers per connector go up in steps of 10 (e.g. the first sensor
has channels M0, M10, M20, M30, the second sensor has channels M1, M11,
M21, M31 etc.).
Device-internal channels:
A further innovation on this device is its four additional device-internal chan-
nels. The first of these M9 is programmed by default as differential channel M1
– M0. This only happens, however, if there are two sensors with the same
units and same decimal point position connected at measuring points M0 and
M1. However, all four channels can be programmed with any other function
channels (e.g. U-Bat, VK, average, volume flow, etc.); (see Manual 6.3.4). The
reference channels used are by default Mb1 = M1 and Mb2 = M0 but this can
be modified (see Manual 6.3.4).
The advantage of device-internal channels is that when using several sensors
for the same application these sensors do not have to be reprogrammed and
can be exchanged without losing the function channels. However, if the whole
application operates with just one sensor, then programming on the sensor
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