Instructions

UM-0085-B09 DT80 Range User Manual Page 376
RG
The following diagram shows the required wiring in detail. In this case a DT80 is shown connected to two CEM20s.
Several K-type thermocouples are also shown, connected to analog inputs on the CEM20s and on the logger itself.
Using this "dual isolated" method of connecting thermocouples (as per V2 – Independent Voltage Inputs (P305)), up to
86 fully isolated thermocouples could be connected – 40 on each CEM20 (two per analog input) plus another 6 on the
remaining 3 analog inputs (inputs 3, 4 and 5) on the DT80.
Figure 173: A DT80 connected to two CEM20s and set up to measure an array of thermocouples
Note the following points about the wiring diagram:
• Each CEM20 is supplied with two pre-wired connecting cables: a power/control cable and an analog cable.
These are suitable for connecting the first CEM20 the logger. To connect the second and subsequent CEM20s,
it will be necessary to replace the "5+2" terminal connector on one end of the power/control cable with a single
4-way terminal block to suit the output on the CEM20. It may also be necessary to extend the length of the
analog cable.
• Shielded cable is recommended. The cable shield should be connected to DGND at one end only, as shown in
the diagram. It is not necessary for everything to use the one DGND terminal – shields may be connected to
any of the DGND terminals on the logger, or to the earth point on the metal end plate.
• The maximum total cable length, from the DT80 to the last CEM20 in the chain, is 100 metres.
Shield
Shield
D
5D 6D 7D 8D GND
WK 12V
1
* + – #
2
* + – #
3
* + – #
D 5D 6D
12V GND Out Out
1
* + – #
2
* + – #
* + – #
To Logger
D
12V GND 5D 6D
D 5D 6D
12V GND Out Out
1
* + – #
2
* + – #
102TK
D
12V GND 5D 6D
DT80
CEM20 #1
CEM20 #2
102*TK
101TK
101*TK
202TK
202*TK
201TK
201*TK
3TK
3*TK
Switch
Setting
Switch
Setting
* + – #
To Logger