Description

New version of TTL/COMS/UART serial port to MBUS main module

According to the requirements of foreign customers, the product RE needs to be verified. The following is the RE test report

The new version of TTL/COMS/UART serial port to MBUS main module is used for MBUS meter reading applications of water, gas, heat and meters. The unique short-circuit protection function can quickly enter the protection state after the bus is short-circuited, and can be self-recovery after cancellation, short-circuit protection Ultra-low power consumption in state. The module is compatible with a variety of TTL levels, and can be flexibly used in other modules such as wireless RF to MBUS module, GPRS to MBUS, 485 to MBUS and so on. In addition, fixed 3.3V level modules can be provided. If you need fixed level modules, please contact customer service!

Features

Fully compliant with MBUS international standard EN1434-3 and Chinese national standard CJ/T188-2018

Wide operating temperature

Low operating power consumption

Overload protection and low power consumption

Short circuit protection and low power consumption

Wide voltage power supply 4-15VDC

Flexible and customizable bus voltage

Small size, easy to integrate into other systems

20 standard MBUS slave devices can be carried according to the load

TTL level can be set externally, flexibly compatible with different voltage systems

The module has no self-receiving and bit error phenomenon within the normal load range

Communication baud rate 300-9600 can be adapted to a maximum of 19200bps

Ultra-long communication distance, extremely low bit error rate

Very low bus parasitic capacitance, 300-19200bps no-load, full-load waveform without distortion

Typical application

Connect the slave stations (user water meter, user heat meter, user gas meter, etc.) to the MBUS interface in parallel in sequence

Connect the module serial port and other interfaces to other systems

System power

The module supports 4-18V wide voltage power supply, and the minimum voltage can be reduced to 4V under light load. maximum load

The number is not allowed to exceed 20. Excessive load will cause the module to enter the overload protection state.

TTLVCC is the power supply for the serial port signal level setting and must be input. TTLVCC pin input 3.3V, TXD and RXD level is 3.3V; TTLVCC pin input 5V, TXD and RXD level is 5V.

load capacity

The maximum load current of the MBUS bus is Ic60mA, the quiescent current of the slave station is represented by Is, and the dynamic current of the slave station is represented by Is.

The stream is represented by It, and the number of loads is represented by N. Calculate the number of loads according to the maximum static current Is 5mA of the slave station, and the maximum dynamic current It20mA

Load quantity N= (Ic-It)/Is= (60-20) /5 =8

The maximum load current Ic of MBUS bus is 60mA, the quiescent current of the slave station is represented by Is, the dynamic current of the slave station is represented by It, and the number of loads is represented by N. Calculate the number of loads according to the standard quiescent current Is 3mA of the slave station, and the maximum dynamic current It20mA

Load quantity N= (Ic-lt)/Is= (60-20) /3= 13

Calculated according to the standard static current of the slave station of 3mA, the maximum number of modules loaded is 13; if the slave station is static

The current is 1.5mA, and the maximum number of modules loaded is 26. The number of modules loaded is affected by factors such as the static current, dynamic current and wires of the slave station. The actual loaded number is subject to the test number.

Overload protection

After the bus is short-circuited, the bus is automatically shut down internally, and the module enters the protection state. OVERLOAD indicates that the pin outputs a low level. It is about 1 to 2 seconds to detect whether the secondary bus is in a short-circuit state. During the detection of the failure, the module will automatically return to normal, and the OVERLOAD indicator pin will automatically return to a high level. After the module enters the protection, the power consumption is low and the host will not fail (hint: after the overload and short circuit fault is cancelled, it can recover by itself without re-powering).

Note: The self-protection of the module will not be damaged after the MBUS bus is short-circuited, but try to avoid long-term overload or short-circuit, and the external power supply used should have the short-circuit protection function as much as possible.

Interface Description:

1 pin VIN: power input interface

2 feet GND: system ground

3-pin RXD: data receiving pin, connected to external device RXD (note that the serial port does not need to be crossed)

4-pin TXD: data transmission pin, connected to external device TXD (note that the serial port does not need to be crossed)

5 feet OVERLOAD: overload short circuit fault output pin

6-pin TTLVCC: TTL level setting pin

M+ pin: MBUS bus output interface

M-pin: MBUS bus output interface

Recommended circuit:

typical application

Battery powered application diagram

Battery-powered applications usually have high power consumption requirements. When the module is not working, turn off the power supply, and start the power supply to start working. It is recommended to add a switch circuit to the power supply part of the module, as follows.

Fixed 3.3V version application diagram

Power switch circuit recommendation

The TTLVCC power switch circuit is controlled by the I0 port of the MCU. If a triode is used instead of a MOS tube, pay attention to increase the current limiting resistor.

Power consumption curve

figure 1

figure 2

statement:

All components of this module are exposed outside, and customer debugging requires a certain amount of hands-on ability and professional knowledge, and other strong electricity cannot be touched during use!