User`s manual

28 CMX34GS cpuModule BDM-610000082 Rev A

Auxiliary Power (CN3)

The Auxiliary Power connector (CN3) can be used to supply power to devices that are attached to the

cpuModule. These devices include hard drive, front-end boards for data acquisition systems, and other devices.

Power can also be conveyed to the module through the Auxiliary Power connector (CN3). The cpuModule only

requires +5 V

, +12 V

, and ground for operation.

If using the Auxiliary Power connector to power the system, care must be taken to ensure good power

connections. The power and ground leads must be twisted together, or as close together as possible to reduce

lead inductance. A separate lead must be used for each of the power pins. All 5V pins, 12V pins, and all ground

pins must be connected. Do not use wire smaller than 20 gauge, and take care to ensure the length of the wire

does not exceed 2 ft. The power supply solution must be verified by measuring voltage at the Auxiliary Power

Connector and verifying that it meets the input voltage specifications. The voltage at the connector should be

checked with an oscilloscope while the system is operational.

Note Although it is possible to power the cpuModule through the Auxiliary Power connector, the

preferred method is to power it through the bus connector from a power supply in the stack. The

cpuModule can have large current transients during operation, which make powering it through wires

difficult. Powering through the bus eliminates such problems as voltage drop and lead inductance.

WARNING This 12-pin power connector is not compatible with previous generations of RTD

cpuModules.

WARNING If you connect power incorrectly, the module will almost certainly be destroyed. Please verify

power connections to the module before applying power.

Table 9 Auxiliary Power Connector (CN3)

Pin Signal Function

1GNDGround

2 +5 V +5 Volts DC

3 +5 V +5 Volts DC

4GNDGround

5GNDGround

6 +12V +12 Volts DC

7 +12V +12 Volts DC

8GNDGround

9GNDGround

10 +5 V +5 Volts DC

11 +5 V +5 Volts DC

12 GND Ground