PUSR USR-DR124 (01) PDF Document

The PUSR USR-DR124 has the following features:

• A new LoRa spread spectrum modulation technology based on the Sx128x chip.

• Lipstick size, small size, guide rail installation.

• Supports pass-through transmission, fixed point, and master-slave transmission, applicable to various scenarios.

• Supports relay data transfer.

• Supports FLRC/LoRa modulation for high and low speed, medium and long-distance transmission.

• High power transmission, 12/27dBm optional, up to 5-8 km.

• Operates on the 2.4GHz unlicensed frequency band, supporting 2.4GHz-2.5GHz.

• Modbus is transparent and simple to use.

• Remote configuration of parameters via upper computer or instructions.

• LORA signal monitoring with an indicator light to display signal quality and interference.

• LBT (Listen Before Talk) function detects channel interference before sending data to prevent conflict.

• Data retransmission mechanism to ensure reliability.

• Data transmission encryption to improve confidentiality.

• A hardware watchdog function to prevent equipment downtime and ensure quick recovery.

The PUSR USR-DR124 is suitable for the following applications:

• Wireless smart metering industry

• Wireless control of smart street lights

• Smart agricultural systems and intelligent irrigation remote control

• Smart site equipment monitoring, such as tower crane operation status

• Smart oil field and oil well condition monitoring

• Smart home and industrial sensors

• Power distribution cabinet power detection and computer room monitoring

• Intelligent building energy monitoring

The transparent transmission protocol means that the transmission process does not affect the content of data; what is sent is the same as what is received. To set up transparent data transfer, two or more devices must have the same settings.

Parameter Setting Steps:

a. Multi-transport mode: The sender and receiver select transparent transport.

b. Modulation mode: The transmitter and receiver select the same modulation mode (e.g., LoRa).

c. Communication frequency band: Set the same frequency band.

d. Communication rate: Set the same rate.

e. Target address: Set the same target address.

Example Configuration:

In broadcast mode, any data sent by one party can be received by all other devices on the network. Both the transmitting and receiving devices must be set to broadcast mode.

Parameter Setting Steps:

a. Multi-transmission mode: The sender and all receivers select broadcast.

b. Modulation mode: The transmitter and all receivers select the same modulation mode (e.g., FLRC).

c. Communication frequency band: All devices are set to the same frequency band.

d. Communication rate: All devices are set to the same rate.

Example Configuration:

Fixed-point transmission allows you to dynamically change the destination address and channel for each data packet. The data format is: Destination Address (16-bit) + Channel Identifier (16-bit) + Data.

Parameter Setting Steps:

a. Data transmission mode: Both the sending and receiving ends set the mode to fixed-point.

b. Modulation mode: The transmitter and receiver select the same modulation mode.

c. Communication frequency band: No limit to the frequency band set on the devices, as it will be specified in the data packet.

d. Communication rate: All communication equipment is set at the same rate.

e. Target address: The sender must format the data with the target’s address and channel. For example, to send “123456” to a receiver with address 66 (0x0042) and channel 3, the sent data would be `004203123456`.

Example Configuration:

This mode is for one master and multiple slaves. The master sends data to specific slaves using the format: Slave target address (16-bit, 1 byte) + Data. The slave sends data directly to the master without this protocol format.

Parameter Setting Steps:

a. Data transmission mode: Set the master-slave mode for both master and slave devices.

b. Master-slave machine setup: Select “master” at the master device end and “slave” at the slave device end.

c. Modulation mode: The transmitting and receiving ends should choose the same modulation mode.

d. Communication frequency band: All devices should be set to the same frequency band.

e. Communication rate: All devices should be set to the same rate.

f. Target address: No restrictions on the communication devices’ own address settings.

Example Configuration:

In this example, the Master sends data `0042123456` where `0042` is the hexadecimal address for slave `66`. The slave receives `123456`.

Relay networking increases transmission distance and data penetration. Devices can be set as a Network Terminal or a Network Relay.

• Network terminal: This device is the start or end point of the data transmission. When a terminal receives a relay data packet matching its group number and target address, it outputs the data to its serial port and does not forward it further.

• Network relay: A device in relay mode listens for data. If a received packet’s group number and address match its own, it outputs to the serial port. If they don’t match, it checks if the packet’s group number matches its relay forwarding rules. If there’s a rule (e.g., forward data from group 1 to group 2), it changes the group number in the packet and retransmits it. If there’s no rule, the data is discarded.

• Group number carried in the data: After a relay rule is set, the group number is converted according to the relay rule when the receiver receives the data.

• Relay Rule: Defines how group numbers are converted. For example, a rule of `1 -> 2` means that when a packet with group number 1 is received, its group number is changed to 2 before being retransmitted.

Important Notes:

1. All devices in the relay network must be set to use the same frequency band and data rate.

2. Only devices with the relay function enabled can communicate with each other.

Parameter Setting Steps:

a. Data transmission mode: Both transmitting and receiving ends select transparent transmission.

b. Modulation mode: The transmitting and receiving ends select the same modulation mode.

c. Relay mode: Turn on the relay switch. Set the relay group number and relay rules for each device.

d. Communication frequency band: All devices shall be set to the same frequency band.

e. Communication rate: All devices shall be set to the same rate.

f. Target address: The transmitting end and relay devices should have different target addresses. The final receiving end should have a target address matching the previous relay device.

Example of a 2-Relay Setup:

Description of device roles in the example:

• Sending End: Set as Network Terminal in group 1.

• Relay 1 Device: Set as Network Relay with rule `1 -> 2`. It receives data for group 1, changes the group number to 2, and forwards it to the next device.

• Relay 2 Device: Set as Network Relay with rule `2 -> 3`. It receives data for group 2 from Relay 1, changes the group number to 3, and forwards it.

• Receiving End: Set as Network Terminal in group 3. When it receives data with the correct target address and group number (3), it outputs the data to its serial port and stops forwarding.

The signal detection function helps determine if there is interference in the operating frequency band and assesses the signal quality during data transmission. This helps in selecting appropriate LORA parameters and ensuring stable data transmission.

There are two modes for signal detection:

1. Channel environment detection (Single device):

After enabling this function, the device reads the signal quality (SNR/RSSI) in the current environment at 1-second intervals and outputs the values through the serial port every 3 seconds. Generally, if the RSSI value is lower than -100dBm and the SNR is lower than 0dB, it indicates interference, and the frequency band should be changed.

2. Wireless data transmission signal detection (2 or more devices):

After enabling this function, when a device receives data from a transmitting end, it will append the instantaneous signal quality (SNR/RSSI) to the data and output it through the serial port. Generally, if the RSSI is lower than -110dBm and the SNR is lower than -5dB, the distance between devices may be too far or there are too many obstacles. In this case, you can reduce the working rate or decrease the distance between devices.

Note: The FLRC modulation method only supports detecting the RSSI value.

When the additional data transmission function is enabled, the receiving device can automatically add extra information to the received wireless data. This can include the node ID of the sending device, the SNR (signal-to-noise ratio), and the RSSI (received signal strength indicator). This is useful for identifying the source and quality of the data.

Parameter Setup:

a. Data transmission mode: Sender and receiver select transparent transmission.

b. Modulation mode: Transmitter and receiver select the same modulation mode.

c. Communication frequency band: Set the same frequency band.

d. Communication rate: Set the same rate.

e. Target address: Set the same target address.

f. In the configuration software, under “Advanced Set”, select the desired format for “DataTranInfo” (e.g., NodeID+Data, or NodeID+Data+SNR+RSSI).

Example:

When using LoRa data transmission, the LBT (Listen Before Talk) function can be enabled. Before sending data, the device listens to the ambient noise of the current frequency band. If the noise exceeds a certain threshold, the data will be sent with a delay. This feature can greatly reduce packet loss and packet error, improving the success rate of data transmission in harsh or busy radio environments.

The data retransmission feature ensures successful data transmission in challenging environments. When enabled, it activates a response mechanism where the sender waits for a confirmation feedback after transmitting data. If a confirmation is received, the transmission is successful. If no response is received within the timeout period, the transmission is considered failed and will be attempted again. A maximum of three retransmissions is allowed.

Note: Retransmission is not supported in relay mode.

The wireless remote configuration function allows you to read and write device parameters remotely using the upper computer software or AT commands. The target device that you want to configure must be in instruction mode. There are two ways to configure a remote device:

1. Specify Node Configuration:

This method allows you to configure a specific remote node by its Node ID. You will need to know the channel and rate of the remote device to communicate with it for configuration.

2. Search Configuration:

This method searches for discoverable nodes on the same channel and displays them in a list on the host computer. You can then select the target node from the list and configure its parameters using the parameter bar on the right side of the software.

Remote AT commands follow a specific protocol for setting parameters. The device information is output in sequence, and OK or ERR-5 is returned after the arrival time.

Scan for devices:

Command: `AT+SCANCMD=,{{,}}`

Example Response:

+SCANCMD:

1,,,

2,,,

OK

Read specific device parameters:

Command: `AT+READCMD=,,,<#CH#VER#...#>`

Example Response:

+READCMD:#CH:8#VER:1.0.0.000000.0000#

OK

Note: The maximum length of response content is 110 bytes. The timeout is 25 seconds.

Write (configure) remote device parameters:

Command: `AT+WRITECMD=,,,<#CH=8#LBT=1#...#>`

Example Response: OK

Note: Setting a parameter requires a restart to take effect. Send the parameter content `<#Z#>` command to restart the configured device. The content length is up to 110 bytes and the timeout is 2 seconds.

To upgrade the firmware on the PUSR USR-DR124, follow these steps:

Entering Upgrade Mode (Choose one method):

• Method 1 (AT Command): Open the settings software, connect to the serial port, click to enter configuration mode, then manually enter `AT+BOOT=1` to activate serial port upgrade mode.

• Method 2 (Hardware): Set the device’s Reload pin to low and then power it on to enable serial port upgrade mode.

Firmware Upgrade Procedure:

1. In the configuration software, click “Firmware Upgrade”.

2. A prompt may appear stating that the upgrade may cause parameters to revert to factory settings. If you select “Confirm”, follow the prompts to save. The “Firmware Upgrade” software will then pop up. If you select “Cancel”, the software will open directly.

3. In the upgrade software, select the corresponding serial port.

4. Open the provided upgrade firmware (*.hex) file.

5. Click “Download” and wait for the download to complete.

Follow these steps to read and configure parameters for the USR-DR124 using the supporting software:

1. Click the serial port configuration button in the drop-down menu of the “Open Serial Port” button. Select the serial port connected to the node, and set the baud rate, parity, data bit, and stop bit to match the node’s parameters (default: 115200, NONE, 8, 1). Click the “Open Serial Port” button.

2. Click the “Enter Configuration Status” button. The node will reply with `+OK`, indicating it has entered AT command mode.

3. Select the desired protocol (e.g., point-to-point).

4. Click the “Read Parameters” button. The software will automatically read and display the node’s parameter information.

5. You can now view and modify the node parameters in the basic parameters section.

6. After making changes, click the “Set Parameters” button. The software will write the new parameters to the node. The node will then restart, and the new parameters will take effect. If you were only reading parameters, click the “Exit Configuration Status” button to exit AT command mode.

To switch the PUSR USR-DR124 from other modes to the AT command mode, follow this procedure through UART. The default UART port parameters are: baud rate 115200, no parity, 8 data bits, 1 stop bit.

The procedure requires specific timing:

1. Input “+++” on UART. After the module receives “+++”, it will return a confirmation code “a”.

2. Within the required time frame, input the confirmation code “a” on UART. After the module receives the confirmation code, it returns “+OK”, and then successfully enters the AT command mode.

The sending command format must end with a carriage return ``, line feed ``, or both ``.

Module Reply Format (Echo Disabled)

• Setting Parameters: `OK`

• Querying Parameters: `+CMD:PARAOK`

Where `CMD` is the command word and `PARA` is the parameter.

If you are experiencing shorter than expected transmission distance, check the following:

• If the antenna is inside a metal shell or a basement, the signal will be attenuated.

• Too many obstacles in the line-of-sight communication path will reduce distance.

• Heavy fog or rainy days can negatively affect signal transmission and increase packet loss.

• Testing near the ground gives poor results. The antenna should be at least 2 meters above the ground.

• If the data rate is set too high, the spreading factor and bandwidth may be inappropriate, resulting in a shorter distance.

• Poor matching between the antenna and the module, or low antenna gain, will lead to a short communication distance.

To prevent damaging your PUSR USR-DR124, follow these precautions:

• Before use, ensure the power supply meets the recommended specifications (8-24V, 12V recommended). Exceeding the maximum value may burn out the equipment.

• During installation and use, take anti-static precautions to prevent damage.

• Use a stable power supply and try to reduce fluctuations. Large fluctuations can cause damage.

• Unless necessary, do not use the device in an environment with extremely low temperatures. Also, be aware of potential short circuits caused by water accumulation and corrosive gases.

Slow data transmission speed can be caused by a couple of factors:

• Wireless Rate: There is a trade-off between transmission speed and distance. A lower wireless rate results in slower transmission speed but a longer transmission distance. Conversely, a higher rate provides faster speed but a shorter distance.

• Serial Port Baud Rate: Using a serial port with a low baud rate will result in slow data transmission to and from the device.

If you are experiencing data transmission issues like garbled codes or errors, consider these sources of interference:

• Other devices operating on the same frequency band nearby. Try changing the communication channel or moving away from the interference source.

• Poor quality antenna feeders and extension lines can lead to errors in signal transmission.

• Large-scale noise generated on the bottom board (if integrated into a larger system) can interfere with data reception.

• An unreasonable power supply setting that does not meet regulations can result in garbled codes.