Potential Separation - Ahlborn ALMEMO 5690-2M Operating Instructions Manual

8. Connecting the transducers
via a 10-fold connector (ZA 5690-MU) each with four screw terminals A, B,
C, D, in the same way as any standard ALMEMO
4.1). Sensors requiring a power supply or an ALMEMO
special interface circuitry (e.g. humidity sensors, rotating vanes, etc.) can-
not be connected in this way. The new connector ZA 5690-MU with a larger
EEPROM now permits 4 channels per sensor, i.e. 40 channels altogether;
on the old connector ZA 5590-MU there are only 10 channels available.
Measuring point numbering is as described above, namely by means of a
code switch internally on the board. For this purpose the module must be
withdrawn and the number on the switch multiplied by 10 (4 = measuring
point 40). All sensors can be programmed individually but their program-
ming data is all saved together in a common EEPROM located in the con -
nector. A cold junction sensor is also provided for thermocouples. Two limit
value relays, operating separately for maximum and minimum, can be con-
tacted in the connector; these can only be used with an appropriate selec-
tor switch board option.
3. Selector switch board U-TH (9) has 10 inputs for thermocouples with a
thermal connector. The sensor data is saved to an EEPROM on the board;
automatic sensor recognition is therefore not possible. Measuring point
numbering is by means of the code switch internally on the board (see
above). This module occupies only 1 plug-in slot but if arranged in series
one dummy panel must be inserted between in order to operate the con-
nector.
4. Selector switch board U-KS (10) also has 10 inputs; these are
led directly onto two 20-contact plug connectors with terminals.
Sensors can be connected via terminals A, B, C, D, with the usual
wiring arrangement. (s. Man. 4.1) In order to feed in the wires the
outside connectors must be opened by inserting a narrow screw-
driver in the inside holes. The sensor data is saved to an EEP-
ROM on the board; automatic sensor recognition is therefore not
possible. Measuring point numbering is by means of the code
switch internally on the board (see above). This module, similarly, occupies
1 plug-in slot only.
Or alternatively the UKSI cards are available with shunts for 20-mA signals
(terminals A(-) and B(+), ´mA ´ or ´%
for 10-V signals (terminals A(-) and C(+), ´mV 2´). This module is only suit-
able for thermocouples if these are connected with copper wires via an
isothermal block with integrated cold junction sensors; (see Manual 6.7.3).

8.4 Potential separation

When organizing a properly functioning measuring setup it is very important to
ensure that no equalizing current can flow between sensors, power supply, and
peripherals. This will be the case so long as all points lie at the same potential
or unequal potentials are electrically isolated.
22 ALMEMO ® 5690-2M
®
connector; (see Manual
´) or the UKSU cards with dividers
®
connector with