Rockwell Automation 1762-Lxxxx MicroLogix 1200 Programmable Controllers - Manual (Page 143)

1 Publication 1762-UM001G-EN-P - March 2011
Appendix
F
System Loading and Heat Dissipation
System Loading Limitations When you connect MicroLogix accessories and expansion I/O, an electrical
load is placed on the controller power supply. This section shows how to
calculate the load and validate that the system will not exceed the capacity of
the controller power supply.
The following example is provided to illustrate system loading validation. The
system validation procedure accounts for the amount of 5V dc and 24V dc
current consumed by controller, expansion I/O, and user-supplied equipment.
Use the System Loading Worksheet on page F-4 to validate your specific
24-point controller configuration.
Use the System Loading Worksheet on page F-9 to validate your specific
40-point controller.
Current consumed by the processor, memory modules, and the real-time clock
modules has already been factored into the calculations. A system is valid if the
current and power requirements are satisfied.
System Current Loading Example Calculations (24-point
Controller)
Table F.1 Calculating the Current for MicroLogix Accessories
Catalog Number Device Current Requirements Calculated Current
at 5V dc (mA) at 24V dc (mA) at 5V dc (mA) at 24V dc (mA)
1761-NET-AIC
(1)
when powered by the base unit communications
port, selector switch in the up position
0 120 0 120
Subtotal 1: 0 120
(1) This is an optional accessory. Current is consumed only if the accessory is installed.