Model: PMM0912
Document version: 1.2
Date: October 2020
UART/TTL to RS485 Converter Module
X86 BASED EMBEDDED INDUSTRIAL COMPUTER
KEY FEATURES AND SPECIFICATIONS DESCRIPTION
Compatible with 3.3V and 5.0V power supply and signals PMM0912 is a TTL to RS485 converter module via MAX485 TTL
Supports baud rate: 110-256000 bps to RS-485 Interface chipset which allows ICs to use RS-485
differential signaling for robust long-distance serial
Transmittance distances up to 1200 meters
communications. This module allows for data transmission and
Operating temperature: -40 to 800C communication of a CPU/MCU with any 2-wire RS485 device
Very high EMC and EMI performance over large distances up to 1200m (4000’).
RXT and TXD signal indicator LEDs to monitor, send and
receive status Earthing the module by connecting its terminal to ground gives
120 Ohm terminal resistors it an excellent anti-jamming and anti-lightning effect, thus
Support multi-machine communication, allowing access making it more secure and perfect for industrial use.
for up to 32 devices on bus Moreover, it has the ability to work under difficult
environmental conditions.
Electrical interference and noise is greatly reduced by the
presence of a large copper area
WIRING RS-485 MODULE
Radio transmission anti-jamming and lightning protection.
Module size: 43mm X 18mm X 3mm
The Two differential data lines (labeled as D-&D+) on the
Vertical and horizontal mounting options, compatible with
output side of the module are connected to the
standard DIP/SIP pinout
communication network, the wiring should be straight
RoHS Compliant
through, where D- on one end should be connected to D- on
Proven PCB Layout the other end and D+ connects to D+.
Fully Assembled and Tested
The wires should ideally be twisted and shielded within one
cable, this method is important as it runs for longer where
there is a lot of electrical noise. The shield or the common
BOARD PINOUT ground is labeled as E in output side of the module.
BOARD PINOUT DESCRIPTION
12 13 14 15
PINs DESCRIPTION
1,5,6,7,12,13 NOT CONNECTED
2 D+ DIFFERENTIAL OUTPUT
3 D- DIFFERENTIAL OUTPUT
4 SHIELD / COMMON GROUND
8,15 TTL/UART GND
9 TTL/UART RX
10 TTL/UART TX
11,14 (VCC) POWER SUPPLY: 5VDC OR
1 2 3 4 5 6 7 8 9 10 11 3.3VDC
NOTE TTL level should match the
connected VCC
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SCHEMATIC DIAGRAM
MULTI-DROP SUPPORT FOR MULTIPLE DEVICES
A significant benefit of RS-485 is that it supports up to 32
devices on the same cable, commonly referred to as a ‘multi-
drop’ FIGURE (2-2).
These devices are typically setup in a Master/Slave configuration
with one Master and one or more Slave device. Since they all
share the same bus, to avoid conflict the Slave devices only talk
when they are asked by the Master such as requesting a
temperature reading.
FIGURE (2-2) MULTI-DROP CONNECTION
DIMENSIONS (mm)
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ORDERING INFORMATION
Part Number Description
PMM0912 UART/TTL to RS485 Converter Module
CUSTOMIZED REQUIREMENT
For any customized inquiries and orders, contact us
on [email protected]
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