SAI140 Modbus RTU Over RS485
to Analogy Input Quick Start Guide
JerryPeng 0975-365-352
www.maxlong.com.tw
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| http://www.maxlong.com.tw/product-detail/lora-converter |
Introduction
SAI140 provides 4 analogy inputs selective from 4~20 mA and 0~10V by onboard jumper settings. It’s sample rate 5 times/second (4 inputs).
One RS485 Serial Port (Terminal Block interface) support Modbus RTU protocol.
Notes:
Word type : Unsigned Integer
Resolution : 16 bits
Wording order : High byte in the front, Low type in the back.
The correct value from analog input should be the obtained value divided by 1000.
1.1 Product Views
1.2 Wiring Architecture
Configuration
2.1 Analogy Type Settings
Note: Analog Inputs each selective of 4~20mA OR 0~10V by onboard jumper Settings.
2.2 Configuration Via Windows Utility
Step1➔ Open and configure SAI140 via the “SCAI4_TestTool”
Step2➔ Configure the test tool (as shown below)
Step3➔ After configure COM port parameters then Click “Connect”
Step4➔One should get ‘Connected” from SAI140 And now you have successfully connected to SAI140.
2.3 Function Test
- Voltage test
- Current test
- VO Settings
2.4 Modbus Command Set
A basic MODBUS command always takes two main parameters：
- ID Address: Designated to receive this Command ID address。
- Function Code: This Command function。
The reception to the Command element will return a Response inform the completion of action in response to the remote or the value returned by the read, Response Command format in the format is basically the same, but also have ID Address and Function code in order to master identification, the following table for common Function code order.
1. MODBUS RTU Protocol
The following MODBUS functions are supported.
| Function code | Description |
| 0x03 | Read Holding Registers |
| 0x06 | Write Single Register |
MODBUS Protocol Address Map
| MODBUS Register | HEX | Function | Description | Action |
| 0000 | 0106 | Read/Write Modbus device Address And Baud Rate Setting |
High byte: Modbus device Address The rage is 1~247 Low byte: Baud Rate Setting 1: 2400 2: 4800 3: 9600 4: 14400 5: 19200 6: 38400 7: 115200 |
R/W |
| 0001 | 0600 | Data length , Parity, and stop bits Setting | High byte: Data length , Parity, and stop bits. Valid values are : SERIAL_7N1 0x04 SERIAL_8N1 0x06(default) SERIAL_7N2 0x0C SERIAL_8N2 0x0E SERIAL_7E1 0x24 SERIAL_8E1 0x26 SERIAL_7E2 0x2C SERIAL_8E2 0x2E SERIAL_7O1 0x34 SERIAL_8O1 0x36 SERIAL_7O2 0x3C SERIAL_8O2 0x3E Low byte: Reserved |
R/W |
| 0004 | 0018 | Read AI1 voltage | Ex: 0x2710 = 10000 in decimal. It means 10.000V | R |
| 0005 | 0030 | Read AI1 current | Ex: 0x4E20 = 20000 in decimal. It means 20.000mA | R |
| 0008 | 0018 | Read AI2 voltage | Ex: 0x2710 = 10000 in decimal. It means 10.000V | R |
| 0009 | 0030 | Read AI2 current | Ex: 0x4E20 = 20000 in decimal. It means 20.000mA | R |
| 0014 | 2710 | Read AO1 voltage | Ex: 0x2710 = 10000 in decimal. It means 10.000V | R/W |
| 0018 | 1388 | Read AO2 voltage | Ex: 0x1388 = 5000 in decimal. It means 5.000V | R/W |
Example for read Modbus Address and Baud Rate :
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 03 | Function | 03 |
| Starting Address Hi | 00 | Byte Count | 02 |
| Starting Address Lo | 00 | High Byte Data | 01 |
| Quantity of Outputs Hi | 00 | Low Byte Data | 06 |
| Quantity of Outputs Lo | 01 | High Byte CRC | 39 |
| High Byte CRC | 84 | Low Byte CRC | D6 |
| Low Byte CRC | 0A | ||
Ex: High Byte Data 0x01 means Modbus Address = 01. The available rage is 1~247.
Low Byte Data 0x06 means Baud Rate = 38400
For
1 means baud rate is 2400
2 means baud rate is 4800
3 means baud rate is 9600
4 means baud rate is 14400
5 means baud rate is 19200
6 means baud rate is 38400
7 means baud rate is 115200
Example for read AI1 voltage input
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 03 | Function | 03 |
| Starting Address Hi | 00 | Byte Count | 02 |
| Starting Address Lo | 04 | High Byte Data | 00 |
| Quantity of Outputs Hi | 00 | Low Byte Data | 18 |
| Quantity of Outputs Lo | 01 | High Byte CRC | B8 |
| High Byte CRC | C5 | Low Byte CRC | 4E |
| Low Byte CRC | CB | ||
Ex: Data 0x0018 = 24 in decimal. It means 0.024V
Example for read AI1 current input
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 03 | Function | 03 |
| Starting Address Hi | 00 | Byte Count | 02 |
| Starting Address Lo | 05 | High Byte Data | 00 |
| Quantity of Outputs Hi | 00 | Low Byte Data | 30 |
| Quantity of Outputs Lo | 01 | High Byte CRC | B8 |
| High Byte CRC | 94 | Low Byte CRC | 50 |
| Low Byte CRC | 0B | ||
Ex: Data 0x0030 = 48 in decimal. It means 0.048mA
Example for read AI2 voltage input
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 03 | Function | 03 |
| Starting Address Hi | 00 | Byte Count | 02 |
| Starting Address Lo | 08 | High Byte Data | 00 |
| Quantity of Outputs Hi | 00 | Low Byte Data | 18 |
| Quantity of Outputs Lo | 01 | High Byte CRC | B8 |
| High Byte CRC | 05 | Low Byte CRC | 4E |
| Low Byte CRC | C8 | ||
Ex: Data 0x0018 = 24 in decimal. It means 0.024V
Example for read AI2 current input
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 03 | Function | 03 |
| Starting Address Hi | 00 | Byte Count | 02 |
| Starting Address Lo | 09 | High Byte Data | 00 |
| Quantity of Outputs Hi | 00 | Low Byte Data | 30 |
| Quantity of Outputs Lo | 01 | High Byte CRC | B8 |
| High Byte CRC | 54 | Low Byte CRC | 50 |
| Low Byte CRC | 08 |
Ex: Data 0x0030 = 48 in decimal. It means 0.048mA
Example for set Modbus Address and Baud Rate :
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 06 | Function | 06 |
| Data Address Hi | 00 | Data Address Hi | 00 |
| Address Lo | 00 | Data Address Lo | 00 |
| High Byte Data | 02 | High Byte Data | 02 |
| Low Byte Data | 06 | Low Byte Data | 06 |
| High Byte CRC | 08 | High Byte CRC | 08 |
| Low Byte CRC | A8 | Low Byte CRC | A8 |
Ex: High Byte Data 0x02 set Modbus Address as 02. The available rage is 1~247.
Low Byte Data 0x06 set Baud Rate as 38400
For 1 set baud rate as 2400
2 set baud rate as 4800
3 set baud rate as 9600
4 set baud rate as 14400
5 set baud rate as 19200
6 set baud rate as 38400
7 set baud rate as 115200
Example for set AO1 :
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 06 | Function | 06 |
| Data Address Hi | 00 | Data Address Hi | 00 |
| Address Lo | 14 | Data Address Lo | 14 |
| High Byte Data | 27 | High Byte Data | 27 |
| Low Byte Data | 10 | Low Byte Data | 10 |
| High Byte CRC | D3 | High Byte CRC | D3 |
| Low Byte CRC | F2 | Low Byte CRC | F2 |
Ex: High Byte Data & Low Byte Data 0x2710 set AO1 10.000V output
Example for set AO2 :
| Request | Response | ||
| Field Name | (Hex) | Field Name | (Hex) |
| MODBUS Address | 01 | MODBUS Address | 01 |
| Function | 06 | Function | 06 |
| Data Address Hi | 00 | Data Address Hi | 00 |
| Address Lo | 18 | Data Address Lo | 18 |
| High Byte Data | 13 | High Byte Data | 13 |
| Low Byte Data | 88 | Low Byte Data | 88 |
| High Byte CRC | 04 | High Byte CRC | 04 |
| Low Byte CRC | 9B | Low Byte CRC | 9B |
Ex: High Byte Data & Low Byte Data 0x1388 set AO2 5.000V output
2.5 Reset Button
If any chance you forgot the login password or have incorrect settings making this Device inoperable, upon the power is on and the “SYS” LED light on, use a point tip to press this button and hold it for more than 20 seconds the release the point tip. The Device will reboot and all the parameters will be reset to the factory default.
This document is proprietary to Max Long Corporation. Use or disclosure of the document, or the information contained therein, for any purposes other than Max Long purposes is NOT permitted without prior written authorization by Max Long
Documents / Resources
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MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input [pdf] User Guide SAI140 Modbus RTU Over RS485 to Analogy Input, SAI140, Modbus RTU Over RS485 to Analogy Input, RS485 to Analogy Input, Analogy Input |