Honeywell 04230-A-1001 - Power Supply

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MAN0530 Issue 15 - 07/17 Searchline Excel
2104M0506
3.4 POWER SUPPLY
3.4.1 General
The Searchline Excel gas detector requires a power supply from the controller of between
18 VDC and 32 VDC. Ensure that a minimum supply of 18 VDC is measured at the detector,
taking into account the voltage drop due to cable resistance.
Themaximumloopresistanceintheeldcableiscalculatedasfollows(R=V/I)
R loop = (V controller – V detector min) / I detector
Example 1
The controller is supplying a nominal 24 VDC (V controller), the detector minimum allowable
voltage is 18 VDC (V detector min), therefore the maximum allowable voltage drop
between the controller and detector is 6 V, which means a voltage drop of 3 V in each core
(+vecoreand–vecore).
Controller
Excel
Rx
18 V
Field Cable
Signal
+24 V
0 V
3 V
+21 V
(wrt Controller 0 V)
4 – 20 mA
(min)
Example 2
Assume that the power consumption of an Excel receiver (Rx) is 8.0 W. The current required
todrivethereceiverattheminimumvoltage(P/V=I)is8.0/18=444mA(Idetector).
So,themaximumeldcableloopresistance(Rloop)wouldbe6/0.44=13.5,and13.5/2=
6.75Ωpercore,(allowingforcomponentvariations,losses,etc.).
3. INSTALLATION AND OPERATION