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B&B Electronics 3PCISD4A manual RS-422 and RS-485 Termination, 4X Baud Rate Option, RS-485 Pinouts

Models: Four Port, PCI Bus RS-232/422/485 Serial Card CE with Send Data Control 3PCISD4B 3PCISD4A

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5.Set the fourth jumper of JP3 (D) to select the type of RS-485 transmit driver control, RTS or Send Data. Select SD control unless you are sure your software requires RTS control.

6. The bottom jumper of JP3 (E) switches the 120Ω receiver termination resistor in or out. Typically this resistor is not used. In some cases using high baud rates and very long cables, termination is needed. See our RS-422/485 Application Note (available on our websites).

7.Configure each port as above using the table in Appendix B.

RS-485 Pinouts

The pinouts in RS-485 mode are the same as those listed in Table 8 for RS-422 mode.

Explanation of RS-485 Operation

In RS-485 mode, the transmit driver must be enabled to transmit, and set to a high impedance (tri-state) mode at the end of transmission. In two wire (half duplex) mode, the receiver is disabled during transmit, and enabled when not transmitting.

The 3PCISD4 card provides two methods of enabling/disabling the transmit driver: automatic Send Data (SD) control and Request To Send (RTS) control. With automatic SD control, the transmit driver is enabled when data is sent. The driver remains enabled for the transmission time and ten data bits after data transfer is complete. The SD circuit automatically adjusts its timing to the baud rate of the data. With RTS control, software must assert the RTS line to enable the driver and disassert to disable the driver. To select SD control for Port 1, place the fourth jumper of JP3 (D) in the SD (right) position. Place this jumper in the RTS (left) position for RTS control.

The receiver can also be enabled and disabled, a useful feature in two-wire communications to prevent the transmitted data from "echoing back" on its own receiver. The second jumper on JP3 (B) determines the receiver mode. If the jumpers are placed in the 485 position, the "echo" is turned off. This is achieved by disabling the receiver when the transmit driver is enabled. Placing this jumper in the 422 position will hold the receiver enabled at all times.

Refer to the Jumper Mode Table in Appendix B for all ports. More information on RS-485 communications can be found in our RS- 422/485 Application Note (available on our websites).

Documentation Number 3PCISD4x-3903 Manual

Chapter 2

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RS-422 and RS-485 Termination

An 120Ω termination resistor has been provided for the RS-422/485 receivers. Note that termination should only be used in systems with both high baud rates (>19200) and over several thousand feet of cable. If a value other than 120Ω is desired, space for a through hole resistor has been provided on the board adjacent to the surface mount termination resistor. The termination resistors are labeled RTAB, RTBB, RTCB and RTDB for ports 1, 2, 3 and 4 respectively. See our RS-422/485 Application Note for more discussion on termination (available on our websites).

4X Baud Rate Option

Baud rates higher than 115,200 are possible with the 3PCISD4x card in RS-232, 422, or 485 mode. Jumper JP5 controls the clock frequency supplied to the UARTs. By moving this jumper to the *4 (left) position, the clock frequency is increased from 1.8432 to 7.3728 MHz. This multiplies all UART baud rates by 4 times. For example, if the software is set for 57.6 Kbaud, the actual baud rate will be increased by a factor of four to 230.4 Kbaud. In many systems, these higher baud rates can improve throughput significantly. However, remember that baud rates and actual throughput are only proportional if the system can keep up with the communications, otherwise increasing the baud rate effectively only increases the idle time between characters.

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Chapter 2

Documentation Number 3PCISD4x-3903 Manual

B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104

B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104

B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445

B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445

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B&B Electronics 3PCISD4A, 3PCISD4B manual RS-422 and RS-485 Termination, 4X Baud Rate Option, RS-485 Pinouts
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Four Port, PCI Bus RS-232/422/485 Serial Card CE with Send Data Control, 3PCISD4B, 3PCISD4A specifications

B&B Electronics offers a range of high-performance serial communication solutions, and the 3PCISD4A and 3PCISD4B models are standout examples of their exceptional capabilities. These four-port PCI Bus RS-232/422/485 serial cards are designed to meet the demanding requirements of industrial applications by providing reliable, flexible, and efficient data communication options.

One of the main features of the 3PCISD4A and 3PCISD4B cards is their send data control functionality, which ensures that data transmission is managed effectively. This feature is particularly beneficial in environments where data integrity and flow control are paramount. By regulating the rate of data sent, the cards help to prevent packet loss and ensure smooth communication between devices.

These cards support multiple serial communication standards, including RS-232, RS-422, and RS-485, making them versatile and suitable for a variety of applications. RS-232 is commonly used for point-to-point connections, while RS-422 and RS-485 support longer distances and multi-device connections, making them ideal for industrial environments. This flexibility allows users to connect different types of devices, such as sensors, controllers, or modems, without needing multiple interface cards.

Another significant characteristic of the 3PCISD4A and 3PCISD4B is their compatibility with various operating systems, including Windows and Linux. This cross-platform support allows for seamless integration into existing systems and makes setup easier for users. The cards also feature high-speed data rates, which facilitate efficient communication and help maximize performance in data-intensive applications.

Furthermore, B&B Electronics emphasizes quality and durability in their designs. The 3PCISD4A and 3PCISD4B are built to withstand the rigors of industrial environments, incorporating robust connectors and materials that can endure temperature fluctuations and electromagnetic interference. This reliability ensures that operators can trust these cards for continuous operation.

In summary, B&B Electronics' 3PCISD4A and 3PCISD4B four-port PCI Bus serial cards are comprehensive solutions for serial communication. With features like send data control, support for multiple communication standards, compatibility with various operating systems, and a commitment to durability, these cards are ideal for demanding industrial applications that require reliable and efficient data transmission. Whether connecting machines or monitoring systems, B&B Electronics provides the reliability and performance that users can depend on.