MGate MB3000 Modbus Gateway User`s Manual

MGate MB3000 Modbus Gateway Getting Started

Connecting Power

The unit can be powered using the AC adaptor or by connecting a power source to the terminal block, depending on the model. The following instructions are for the AC adaptor:

1. Plug the connector of the power adapter into the DC-IN jack on the back of the unit.

2. Plug the power adapter into an electrical outlet.

3. Follow these instructions to connect a power source to the terminal block:

4. Loosen or remove the screws on the terminal block.

5. Connect the 12~48 VDC power line to the terminal block.

6. Tighten the connections using the screws on the terminal block.

Note that the unit does not have an on/off switch. It automatically turns on when it receives power. The PWR

LED on the top panel will glow to indicate that the unit is receiving power.

For power terminal block pin assignments, please refer to the hardware reference chapter for your model.

Connecting Serial Devices

The unit’s serial port(s) are located on the back panel. There are two options for connecting serial devices, depending on the serial interface:

• You may use a DB9-to-DB9 cable to connect a serial device to the unit. Plug one end of the cable into the port on the unit’s back panel and plug the other end of the cable into the device’s serial port.

• You may make your own customized serial cable to connect a serial device to the unit. For the pin assignments of the unit’s serial port, please refer to Chapter 10. This information can then be used to construct your own serial cable.

If you are connecting a RS-485 multidrop network with multiple devices, please note the following:

• All devices that are connected to a single serial port must use the same protocol (i.e., either Modbus RTU or Modbus ASCII).

• Each master device must get its own port on the unit. If you are connecting a network with both master and slave devices, the master must be connected on a separate port from the slaves. Furthermore, the master will only be able to communicate to Modbus TCP slaves, not to the ASCII or RTU slaves that are connected on a different serial port.

For serial port pin assignments, please refer to the hardware reference chapter for your model.

RS-485 Termination and Pull High/Low Resistors

In some critical RS-485 environments, you may need to add termination resistors to prevent the reflection of serial signals. When using termination resistors, it is important to set the pull high/low resistors correctly so that the electrical signal is not corrupted. For each serial port, DIP switches or jumper settings are used to set the pull high/low resistor values. For all models except the MB3180, a built-in 120 Ω termination resistor can also be enabled.

To modify the termination and pull high/low resistor settings, please refer to the hardware reference chapter for your model.

ATTENTION

Do not use the 1 KΩ pull high/low setting on the MGate MB3000 when using the RS-232 interface. Doing so will degrade the RS-232 signals and reduce the effective communication distance.

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