Powering

Power Connection

Power must be supplied to the device via the Vpri (4.2-16V DC) and/or Vaux (4.2-16V DC) pins. See Main/Aux for pinouts. If power is supplied to both inputs, the 3DM-GQ7 will use the one with the higher voltage. These inputs are common to both connectors, as shown below:

WARNING: Do not connect the same power supply inputs (Vpri or Vaux) to different power supplies. Damage to the device and/or connected equipment may result from improper power supply connection. See the section below on properly powering the 3DM-GQ7.

NOTE: Some other products, such as the GX5, have Vpri and Vaux internally connected. For those products connecting separate supplies to Vpri and Vaux will result in a short circuit between them.

 

Standard Cables

The standard USB cable provides +5V from the host to pin 3 (Vpri). The standard RS232 cable allows a user to connect a power supply to pin 6 (Vaux). Both cables may be used together, but caution is advised when using two of the same cables simultaneously. See the warning above.

 

How to Properly Power the 3DM-GQ7

Case 1 - 1 USB or 1 Serial

The 3DM-GQ7 can powered from a single serial connection or a single USB connection, through either its main or its aux port.

Case 2 - 2 USB Connections

Do NOT connect the 3DM-GQ7to separate computers using standard USB cables. This will short the two computers’ 5V rails together, and, depending on the output impedance and voltage tolerances, excessive current may flow from one PC through the 3DM-GQ7’s Vpri input and back out to the other PC.

A similar situation can occur when using a hub, especially the variety with their own power source. Plug neither or both cables into a hub.

Connecting the 3DM-GQ7 to the same computer with two standard USB cables is generally safe as the power supply tolerances within a single computer are much tighter. It is recommended to use two ports connected to the same internal bus. Typically, these will be physically next to each other.

Case 3 - 1 USB and 1 Serial Connection

The 3DM-GQ7 can be connected using one standard USB cable and one standard RS232 cable. Power may be optionally supplied via the barrel plug on the RS232 cable. In this case, USB provides power to Vpri and the barrel plug provides power to Vaux.

Case 4 - 2 Serial Connections

Two RS232 serial cables may be used simultaneously if only one power supply is used. You can feed the same power supply to both connectors if desired. However, do NOT power them from different supplies.