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4.5.6 Multidrop using RS485 / RS422

Multidrop systems allow one device to act as a ‘network master’, controlling and interacting with the other (slave) devices on the network. The network master can be a controller such as NextMove ES, a host application such as WorkBench v5 (or other custom application), or a programmable logic controller (PLC). RS422 may be used for multi-drop applications as shown in Figure 16. Four-wire RS485 may be used for single point-to-point applications involving only one Baldor controller. If firmware is updated over RS485/RS422, it can only be downloaded to the controller that was chosen in the Select Controller dialog in WorkBench v5.

Network

master

Twisted pairs

TX+

 

TX-

 

RX+

 

RX-

TR

DGND

 

Master and final slave are shown with terminating resistors, TR, typical value 120Ω.

Jumper JP2 connects an internal 120Ω terminating resistor. JP2 is located just behind the serial connector on the NextMove ES card.

Network slave

RX+

RX-

TX+

TX-

DGND

Network slave

TR RX+

RX-

TX+

TX-

DGND

Connect overall shield to connector backshell.

Figure 16 - 4-wire RS422 multi-drop connections

Each transmit/receive (TX/RX) network requires a termination resistor at the final RX connection, but intermediate devices must not be fitted with termination resistors. An exception is where repeaters are being used which may correctly contain termination resistors. Termination resistors are used to match the impedance of the load to the impedance of the transmission line (cable) being used. Unmatched impedance causes the transmitted signal to not be fully absorbed by the load. This causes a portion of the signal to be reflected back into the transmission line as noise. If the source impedance, transmission line impedance, and load impedance are all equal, the reflections (noise) are eliminated. Termination resistors increase the load current and sometimes change the bias requirements and increase the complexity of the system.

4-18 Input / Output

MN1928

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Baldor MN1928 installation manual Multidrop using RS485 / RS422, Wire RS422 multi-drop connections

MN1928 specifications

The Baldor MN1928 is a highly regarded motor designed for a variety of industrial applications, known for its durability and efficiency. This motor is part of Baldor’s extensive range of products, which are engineered to meet the demands of heavy-duty operations.

One of the key features of the Baldor MN1928 is its robust construction. Built with high-quality materials, this motor is designed to withstand harsh environmental conditions often found in industrial settings. The steel frame is not only resilient, but it also enhances the motor's cooling capabilities, enabling it to perform effectively over extended periods.

The MN1928 is equipped with advanced technologies that optimize its performance. One notable technology is the use of high-efficiency induction motor design. This reduces energy consumption significantly and contributes to lower operational costs. The motor is also designed with a continuous duty rating, making it capable of running for long hours without compromising its functionality or lifespan.

In terms of characteristics, the Baldor MN1928 features a reliable ball bearing design, which minimizes friction and wear, ensuring smoother operation and increased reliability. With a horsepower rating that suits a range of applications, it provides the necessary torque and speed to power various machinery effectively. The multi-voltage design allows for versatile installation options, accommodating different electrical systems while ensuring efficient performance.

Another important characteristic of this motor is its ease of maintenance. The design allows for straightforward access to components, making it simple for technicians to perform routine checks and maintenance. This is particularly beneficial in industrial settings where downtime can be costly.

Safety is also a priority in the design of the Baldor MN1928. Equipped with thermal overload protection, it prevents overheating, reducing the risk of damage caused by excessive temperatures during operation. Additionally, the motor complies with various industry standards, ensuring safe operation within diverse environments.

In summary, the Baldor MN1928 stands out as a reliable choice for industrial applications, offering a combination of durability, efficiency, and advanced technology. Its robust construction, high-efficiency design, and safety features make it a preferred option for many enterprises seeking dependable motor solutions.