ircon Modline 4, Installation And Operation Manual

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Section 2 - INSTALLATION
FIG. 2.2 MODLINE 4 MULTIPLE LOAD ELECTRICAL CIRCUIT
2.4
MULTIPLE LOAD SYSTEM
In Fig. 2.2, a recorder, analog indicator and controller are
connected in a series in the loop. The 4 to 20 mA current
determined by the MODLINE 4 flows through all of these
load elements, producing voltage drops proportional to the
resistance of each load element. The total load voltage is
the sum of these voltage drops plus the drop across the
connecting wires.
Assume the resistances are as indicated in Fig. 2.2:
TABLE 2.1
MINIMUM DC SUPPLY REQUIREMENTS
FOR MULTIPLE LOADS
Total Load Total Load Minimum DC
Resistance Load Supply
(ohms) (volts)
(volts)
≥ 50 1 17
100 2 18
200 4 20
300 6 22
400 8 24
500 10 26
600 12 28
700 14 30
800 16 32
900 18 34
1000 20 36
1100 22 38
1200 24 40
With 8 V dropped across the load elements and cables,
a supply voltage of at least 24 V is needed to ensure the
required 16 V minimum for the MODLINE 4 (
see table 2.1 –
Minimum DC Supply Requirements ).
IMPORTANT: DC supply voltage must never
exceed 40 volts!
2-3 ®