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Model 298 ADA-Compliant Emergency Telephone
Pub. 42004-304A
f:\standard ioms - current release\42004 instr. manuals\42004-304a.doc
06/02
AUXILIARY OUTPUT DESIGN EXAMPLES
24 V DC Relay Example
The load is a 24 V relay with a with a coil resistance of 800 ohms. The minimum activation voltage is
19 V. The maximum allowable voltage across the relay is 30 V dc.
Iload = Vload/Rload = 24 V dc/800 ohms = 30 mA
Therefore, the external voltage must be in the range of:
Vmin (load) + Vmax drop <= Vsource <= Vmax (load) + Vmin drop
19 V + 3 V <= 24 V <= 30 V + 0.25 V
48 V DC Relay Example
The load is a 48 V relay with a with a coil resistance of 1400 ohms. The minimum activation voltage is
37 V. The maximum allowable voltage across the relay is 79 V dc.
Iload = Vload/Rload = 48 V dc/1400 ohms = 34.29 mA
Therefore, the external voltage must be in the range of:
Vmin (load) + Vmax drop <= Vsource <= Vmax
37 V + 3 V <= 48 V <= 48 V
Figure 7. Auxiliary Output Connections
