CTI Products EXB-232 Asynchronous Serial System Extender - Manual (Page 22)

68-11089-115
18
building 1 is powering 2 module loads for each IIB plus 2 module loads for the EXB for a total of
4 module loads on the power supply. If another MCN module is added to the MCN network in
either building, an additional power supply would have to be added to the system for the
additional module.
Powering the EXB unit from a customer-supplied DC source
When powering the unit from a customer-furnished power supply, the supply must be current
limited or fused at 1A.
It is recommended that 18-30 VDC be used as power input, although lower voltages can be used.
Since a switching regulator is used in the EXB units, they will draw lower current at the higher
voltages.
At the lower input voltages, the number of modules that can be driven in series is limited.
When an MCN module powers a unit downstream from it, it adds approximately 1.4 V drop from
its power input to the power output on the network connector. Thus, a 12VDC input would only
power two modules before reaching the lower limit of 10V input to the last module. Additional
modules could be powered from the 12VDC input, but you must power the additional groups of
modules through the round DC power connector.