TTL 422 485 PLUS
From Diustou Wiki
Revision as of 11:06, 15 January 2025 by Yousimaier17 (talk | contribs) (Created page with "{{Product |images=400px |categories= {{Category|UART}} {{Category|RS485}} {{Category|RS422}} |brand=丢石头 |features= * Adopts standard 5.08mm...")
| ||||||||||||||||||||||
| ||||||||||||||||||||||
| ||||||||||||||||||||||
Contents
Product Overview
- Adopts original SP3485, offering stable performance and meeting industrial-grade design standards.
- This module enables the conversion between TTL signals and RS485/RS422 signals. It features an onboard automatic transceiver conversion circuit, eliminating the need for "receive-transmit" control, thus facilitating faster and more stable communication between the two interfaces.
- Equipped with a 5.08mm standard terminal block for smooth and secure plug-and-play connectivity.
- The circuit operates on a 5V power supply only. The TTL signal output level is 5V (same as the supply voltage), and the input signal level is 5V (compatible with 3.3V signal input).
- The module requires a power supply to be connected to the TTL terminal during operation.
- Incorporates independent power and signal isolation circuits.
- The onboard digital isolator offers excellent performance characteristics and reliability, enabling signal isolation for more stable signal transmission.
- The onboard DC/DC power isolator provides stable isolated voltage and output short-circuit protection, eliminating the need for additional power supply at the isolation end.
- The TTL terminal is equipped with overcurrent protection and surge protection functions, ensuring stable output of current and voltage and strong impact resistance.
- The RS485/422 terminal features overcurrent protection, surge protection, and lightning surge protection circuits.
- The onboard TVS (Transient Voltage Suppressor) effectively suppresses surge voltages and transient spike voltages in the circuit, protecting downstream circuits and devices.
- The onboard self-resetting fuse ensures stable output of current and voltage, prevents overcurrent, overvoltage, and electrostatic discharge, and offers strong impact resistance.
- The onboard GDT (Gas Discharge Tube) utilizes the discharge tube to direct powerful lightning currents into the ground, protecting subsequent circuits and devices from surge impacts and damage.
- The board includes 120R terminal resistor pads, enhancing signal transmission stability and reducing interference.
- Baud rate support range:
- RS422: ≤2M bps (self-transceiver test; actual use should refer to the baud rate range of the connected devices)
- RS485: ≤2M bps (non-standard value; actual use should refer to the baud rate range of the connected devices)
- The board is equipped with three LED indicators to show the circuit signal transmission and reception status.
- PWR light: Green, power indicator
- TXD light: White, TTL data transmission indicator (data flow: RS422/485 -> TTL)
- RXD light: White, TTL data reception indicator (data flow: TTL -> RS422/485)
Testing Methods
RS485 Testing
- Connect a USB-to-TTL serial module to the TTL port of the TTL 422 485 PLUS module:
- TXD to RXD
- RXD to TXD
- GND to GND
- Connect a USB-to-RS485 serial module to the RS485 port of the TTL 422 485 PLUS module:
- A to A
- B to B
- Connect the power supply to the TTL terminal of the TTL 422 485 PLUS module:
- 5V to 5V
- GND to GND
- Connect the USB-to-TTL serial module and the USB-to-RS485 serial module to the computer, open two serial port debugging assistants, and select the corresponding port numbers.
- Use one of the serial port debugging assistants to send data to the TTL 422 485 PLUS and observe if the receiving window of the other assistant receives the same data as sent. If the data matches, repeat the process in reverse.
RS422 Self-transceiver Testing
- Connect a USB-to-TTL serial module to the TTL port of the TTL 422 485 PLUS module:
- TXD to RXD
- RXD to TXD
- GND to GND
- Short-circuit the pins of the USB 422 485 PLUS module:
- TXD+ to RXD+
- TXD- to RXD-
- Connect the power supply to the TTL terminal of the TTL 422 485 PLUS module:
- 5V to 5V
- GND to GND
- Connect the USB-to-TTL serial module to the computer, open the serial port debugging assistant, and select the corresponding port number.
- Use the serial port debugging assistant to send data to the TTL 422 485 PLUS and observe if the receiving window of the assistant receives the same data as sent.
Hardware Connections
- TTL to RS485 Mode
- TTL to RS422 Mode
Notes
- A power supply must be connected to the TTL terminal during use, and the power GND should be connected to the module's TTL GND and the GND of the TTL device.
- TTL to RS485: RS485 is half-duplex communication. Although this module can facilitate bidirectional communication, it cannot transmit and receive simultaneously in both directions. Even if the UART is full-duplex, it cannot transmit and receive at the same time. In other words, each end of the communication channel can be either a transmitting or receiving end, but at any given moment, information can only flow in one direction.
- TTL to RS422: RS422 is full-duplex communication. This module can enable simultaneous TTL and RS422 signal transmission in both directions without interference, and transmission and reception do not require manual control, making it convenient and efficient.
- The lightning protection and anti-interference design of the RS485/422 interface have been fully considered. When transmitting over long distances in the field, connecting the module's "ground" terminal to the earth can significantly enhance anti-interference and lightning protection, making RS485/422 communication safer. For short-distance indoor transmission, grounding is not necessary.
Data Sheet
Resource Download
FAQ
|
