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DewPro MMY31
3.0
3.1 Wiring, General Guidelines
Caution!
Caution!
The DewPro system contains electronic components that are susceptible
to damage by static electricity. Proper handling procedures must be
observed during the removal , installation, or other handling of internal boards.
3.2 System Configuration, Various
Fig. 4
NOTE: The voltage across the +/- terminal of the DewPro should not fall below 9 V DC.
The maximum loop resistance is an important measure for selection of the supply voltage.
Each device connected to the loop causes a voltage drop. For instance, using a loop-
powered display with an input impedance of 50 Ohm will cause a voltage drop of 1 V DC
at 20 mA following Ohm's law. Connecting the loop to a PLC will cause a voltage drop
across its input.
When designing your loop, add up all voltage losses across the devices connected to the
loop and add 12 V. The sum will be the minimum supply voltage required from the power
supply. Calculate with a 20% safety factor.
If a display is used, configure it to the proper range: -90
for dewpoint corresponding to 4 to 20 mA.
GE General Eastern
Wiring
8888
Installation and Operation Manual
Optional loop powered
display available from
General Eastern, such as Md102
Customers power supply
24 V DC ( 9...32 V DC )
-
~
Power supply
available from General Eastern
8888
-
~
Power supply with display
and optional relay available
from General Eastern such as Md102
o
C to +10
115/230 V
AC
115/230 V
AC
o
o
o
C (- 130
F to + 50
F)
7
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