MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input User Guide

June 14, 2024
MaxLong

SAI140 Modbus RTU Over RS485
to Analogy Input Quick Start Guide

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input

JerryPeng 0975-365-352
www.maxlong.com.tw

| MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - Qr code
2
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http://www.maxlong.com.tw

| 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

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - Product
Views

1.2 Wiring Architecture

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - Wiring
Architecture

Configuration

2.1 Analogy Type Settings

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - 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)

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - SCAI4 test tool
configuration

Step3➔ After configure COM port parameters then Click “Connect”
Step4➔One should get ‘Connected” from SAI140 And now you have successfully connected to SAI140.

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - SCAI4 test tool
configuration 2

2.3 Function Test

  1. Voltage testMaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - Voltage test
  2. Current testMaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - Current test
  3. VO SettingsMaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - VO Settings

2.4 Modbus Command Set
A basic MODBUS command always takes two main parameters:

  1. ID Address: Designated to receive this Command ID address。
  2. 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)
MODBUS Address 01
Function 03
Starting Address Hi 00
Starting Address Lo 00
Quantity of Outputs Hi 00
Quantity of Outputs Lo 01
High Byte CRC 84
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)
MODBUS Address 01
Function 03
Starting Address Hi 00
Starting Address Lo 04
Quantity of Outputs Hi 00
Quantity of Outputs Lo 01
High Byte CRC C5
Low Byte CRC CB

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - voltage
input

Ex: Data 0x0018 = 24 in decimal. It means 0.024V
Example for read AI1 current input

Request Response
Field Name (Hex)
MODBUS Address 01
Function 03
Starting Address Hi 00
Starting Address Lo 05
Quantity of Outputs Hi 00
Quantity of Outputs Lo 01
High Byte CRC 94
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)
MODBUS Address 01
Function 03
Starting Address Hi 00
Starting Address Lo 08
Quantity of Outputs Hi 00
Quantity of Outputs Lo 01
High Byte CRC 05
Low Byte CRC C8

MaxLong SAI140 Modbus RTU Over RS485 to Analogy Input - voltage input
2

Ex: Data 0x0018 = 24 in decimal. It means 0.024V
Example for read AI2 current input

Request Response
Field Name (Hex)
MODBUS Address 01
Function 03
Starting Address Hi 00
Starting Address Lo 09
Quantity of Outputs Hi 00
Quantity of Outputs Lo 01
--- ---
High Byte CRC 54
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)
MODBUS Address 01
Function 06
Data Address Hi 00
Address Lo 00
High Byte Data 02
Low Byte Data 06
High Byte CRC 08
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)
MODBUS Address 01
Function 06
Data Address Hi 00
Address Lo 14
High Byte Data 27
Low Byte Data 10
High Byte CRC D3
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)
MODBUS Address 01
Function 06
Data Address Hi 00
Address Lo 18
High Byte Data 13
Low Byte Data 88
High Byte CRC 04
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

References

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