7. Connection of the Transducers
7. CONNECTION OF THE TRANSDUCERS
Any ALMEMO
®
sensors can be connected to the ALMEMO
®
input sockets M0
to M4 of the measuring instrument (1). For connecting existing sensors it is
only necessary to connect a corresponding ALMEMO
®
connector.
7.1 Transducers
A detailed description of the comprehensive ALMEMO
®
sensor range (see ma-
nual section 3) and the connection of existing sensors (see manual section 4)
to the ALMEMO
®
instruments are provided in the ALMEMO
®
manual. All stan-
dard sensors with ALMEMO
®
connector usually have the measuring range and
dimension already programmed and can be immediately connected to any in-
put socket. A mechanical coding ensures that sensor and output modules can
only be connected to the correct sockets. Furthermore, each ALMEMO
®
connector has two locking levers that snap in when the insertion into the socket
is established and that prevent a disconnection caused by pulling the cable.
Both levers must be pressed on the sides for disconnecting the connector.
Especially for the device ALMEMO
®
2690-8, new sensors with ready-made AL-
MEMO
®
connectors are available. They offer a splash-proof enclosure for the
sockets due to their double sealing lips. For unused sockets there are dummy
connectors.
7.2 Measuring inputs and Additional Channels
The measuring instrument ALMEMO 2690-8 has 5 input sockets (1) that the
measuring channels M0 to M4 are initially allocated to. However, ALMEMO
®
sensors can, if required, provide up to 4 channels so that 20 channels are
available with 5 input sockets. The additional channels can be especially used
with humidity sensors with 4 measuring variables (temperature/humidity/dew
point/mixture ratio) or used for function channels. If required, the sensor can
also be programmed with several ranges or scaling or, depending on the pin
assignment, 2 or 3 sensors can be combined in one connector (e.g. rH/Ntc,
mV/V, mA/V etc.). The additional measuring channels of a connector are incre-
ased in steps of 10 (e.g. the first sensor has the channels M0, M10, M20, M30,
the second sensor has the channels M1, M11, M21, M31 etc.).
Device-internal channels:
An innovation on this device is its four extra additional channels. The first of
these M5 is programmed by default as differential channel M1 – M0. This only
happens, however, if there are two sensors with the same units and same de-
cimal 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, CJ, average, volume flow, etc.); (s. 10.3.10, man. 6.3.4). Mb1 = M1 and
Mb2 = M0 are always used as reference channels by default.
16 ALMEMO 2690-8
