Tyco Safety Products / Software House PI26 User Manual

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Introduction
C-2
apC/8X Technical Manual
Introduction
The apC/8X supplies 12 volts at its connectors; however, the amount of 
power that actually reaches each personality board in a chain is less than 12 
volts.
The RM-4 requires at least 7.5 volts to operate properly. 
The RM-4E requires at least 11 volts to operate properly.
The total voltage is lowered by each reader and by the resistance of the wire. 
Whether the personality board chain needs a local power supply depends on 
all the following factors:
Number of devices on the bus
Current draw of each device
Distance between the devices in the chain
Distance between the devices and the apC/8X
Wire gauge used to connect the readers and the apC/8X
Refer to sections that follow to calculate the power in a chain. Be sure you 
read and understand the instructions and examples in each section before 
beginning to calculate the maximum wiring lengths for your application.