SONBEST SM1901M Current Type 4-20mA Noise Sensor User Manual

SONBEST SM1901M Current Type 4-20mA Noise Sensor

SM1901M uses the standard RS485 bus MODBUS RTU protocol, easy access to PLC DCS, and other instruments or systems for monitoring temperature state quantities. The internal use of high precision sensing core and related devices to ensure high reliability and excellent long-term stability can be customized RS232, RS485, CAN,4 20mA, DC0~5V 10V, ZIGBE E, Lora, WIFI, GPRS, and other output methods.

Technical Parameters

**Product Size

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**How to wiring?

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Application solution

**How to use?

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Communication Protocol

The product uses RS485 MODBUS RT U standard protocol format, all operation or reply commands are hexadecimal data. The default device address is 1 when the device is shipped, the default baud rate is 9600, 8, n, 1

Read Data (Function id 0x03)

Inquiry frame (hexadecimal), sending example: Query 1# device 1 data, the host computer sends the command:01 03 00 00 00 01 84 0A .

For the correct query frame, the device will respond with data:01 03 02 00 79 79 A6, the response the   format is parsed as follows:

Data Description: The data in the command is hexadecimal. Take data 1 as an example. 00 79 is converted to a decimal value of 121. If the data magnification is 100, the actual value is 121/100=1.21. Others and so on.

Data Address Table

Read and modify device address

Read or query device address

If you don’t know the current device address and there is only one device on the bus, you can use the command FA 03 00 64 00 02 90 5F Query device address.

FA is 250 for the general address. When you don’t know the address, you can use 250 to get the real device address, 00 64 is the device model register. For the correct query command, the device will respond, for example, the response data is 01 03 02 07 12 3A 79, the format of which is as shown in the following table:

The response should be in the data, the first byte 01 indicates that the real address of the current device is, 55 3C converted to decimal 20182 indicates that the current device’s main model is 21820, and the last two bytes 00 01 Indicates that the device has a status quantity.

Change devise address

For example, if the current device address is 1, we want to change it to 02, the command is:01 06 00 66 00 02 E8 14.

After the change is successful, the device will return information: 02 06 00 66 00 02 E8 27 , its format is parsed as shown in the following table:

The response should be in the data, after the modification is successful, the first byte is the new device address. After the general device address is changed, it will take effect immediately. At this time, the user needs to change the query command of the software at the same time.

Read and Modify Baud Rate

Read baud rate

The device’s default factory baud rate is 9600. If you need to change it, you can change it according to the following table and the corresponding communication protocol. For example, read the current device’s baud rate ID, the command is:01 03 00 67 00 01 35 D5, and its format is parsed as follows.

Read the baud rate encoding of the current device. Baud rate encoding: 1 is 2400; 2 is 4800; 3 is 9600; 4 is 19200; 5 is 38400; 6 is 115200. For the correct query command, the device will respond, for example the response data is: 01 03 02 00 03 F8 45, the format of which is as shown in the following table:

coded according to baud rate, 03 is 9600, ie the current device has a baud rate of 9600.

Change the baud rate

For example, changing the baud rate from 9600 to 38400, ie changing the code from 3 to 5, the command is: 01 06 00 67 00 05 F8 1601 03 00 66 00 01 64 15.

Change the baud rate from 9600 to 38400, changing the code from 3 to 5. The new baud rate will take effect immediately, at which point the device will lose its response and the baud rate of the device should be queried accordingly. Modified.

Read Correction Value

Read Correction Value

When there is an error between the data and the reference standard, we can reduce the display error by adjusting the correction value. The correction difference can be modified to be plus or minus 1000, that is, the value range is 0-1000 or 64535 -65535. For example, when the display value is too small, we can correct it by adding 100. The command is: 01 03 00 6B 00 01 F5 D6 . In the command 100 is hex 0x64 If you need to reduce, you can set a negative value, such as -100, corresponding to the hexadecimal value of FF 9C, which is calculated as 100-65535=65435, and then converted to hexadecimal to 0x FF 9C. The correction value starts from 00 6B. We take the first parameter as an example. The correction value is read and modified in the same way for multiple parameters.

For the correct query command, the device will respond, for example, the response data is 01 03 02 00 64 B9 AF, the format of which is as shown in the following table:

In the response data, the first byte 01 indicates the real address of the current device, and 00 6B is the first state quantity correction value register. If the device has multiple parameters, other parameters operate in this way. The same, the general temperature, and humidity have this parameter, the light generally does not have this item.

Change correction value

For example, if the current state quantity is too small, we want to add 1 to its true value, and the current value plus 100 correction operation command is:01 06 00 6B 00 64 F9 FD.

After the operation is successful, the device will return information: 01 06 00 6B 00 64 F9 FD, the parameters take effect immediately after a successful change.

Disclaimer

This document provides all information about the product, does not grant any license to intellectual property, does not express or imply, and prohibits any other means of granting any intellectual property rights, such as the statement of sales terms and conditions of this product, other issues. No liability is assumed. Furthermore, our company makes no warranties, express or implied, regarding the sale and use of this product, including the suitability for the specific use of the product, the marketability or the infringement liability for any patent, copyright or other intellectual property rights, etc. Product specifications and product descriptions may be modified at any time without notice.

Contact Us

Company: Shanghai Sonbest Industrial Co., Ltd

• Address: Building 8, No.215 Northeast Road, Baoshan District, Shanghai, China
• Web: http://www.sonbest.com
• Web:     http://www.sonbus.com
• SKYPE: soobuu
• Email: sale@sonbest.com
• Tel: 86-021-51083595 / 66862055 / 66862075 / 66861077

References

• Home-上海搜博实业有限公司
• Home-SONBEST -SONBUS.COM| THE SENSOR COMPANY
• Home-SONBEST -SONBUS.COM| THE SENSOR COMPANY

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