Revision as of 03:33, 23 December 2021

Introduction

Modbus enables communication among many devices connected to the same network, for example, a system that measures temperature and humidity and communicates the results to a computer. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems.

Many of the data types are named from its use in driving relays: a single-bit physical output is called a coil, and a single-bit physical input is called a discrete input or a contact.

Modbus Service is a Windows/Linux system service for WISE Agent to read sensor data from Modbus device or write data into Modbus device. After sensor data are acquired, WISE Agent will upload the data to the WISE-PaaS Cloud.

Modbus Service

JSON Format for upload data

{
   "Modbus_Handler":{
      "Platform":{
         "bn":"Platform",
         "e":[{"n":"Version","sv":"2.0.0"},
              {"n":"Description","sv":"This service is Modbus Service"},
              {"n":"Protocol","sv":"Modbus_TCP"},
              {"n":"Name","sv":"WISE-4012E"},
              {"n":"ClientIP","sv":"127.0.0.1"},
              {"n":"ClientPort","sv":"502"},
              {"n":"Connection","bv":true}]
      },
      "Modbus_Device0":{
         "bn":"Modbus_Device0",
         "e":[{"n":"UnitID","sv":"1"}],
         "Coils":{
            "bn":"Coils",
            "e":[{"n":"LED0","bv":true},
                 {"n":"LED1","bv":true},
                 {"n":"LED2","bv":false}]
         }
      },
      "Modbus_Device1":{
         "bn":"Modbus_Device1",
         "e":[{"n":"UnitID","sv":"2"}],
         "Discrete Inputs":{
            "bn":"Discrete Inputs",
            "e":[{"n":"Switch0","bv":false},
                 {"n":"Switch1","bv":true},
                 {"n":"Switch2","bv":false}]
         }
      }
   }
}

How To

Installation

Prerequisited packages:

1. WISE Agent

   Please download installer from EdgeSense or DeviceOn portal.

2. MQTT Broker

    You can download installer from this link: https://mosquitto.org/download/

Modbus Service Setup:

1. Double click Agent_Modbus_Handler_2.0.x.exe (Download) to start installation.

2. Click "Next" on the Welcome screen.

3. Select Installation Folder and then click "Next" to continue.

4. Click "Install" on the Ready to Install screen to continue.

5. Installation completed, click "Finish" button to exit the Setup Wizard.

Configuration

Config Modbus Connection

1. Open File Explorer and change target folder to the Modbus Service installation folder.

2. Open and edit the file Mobus_Handler.ini

2.1 Give a Name for the platform.

2.2 Set the Protocol.

Modbus TCP Connection:

Protocol=Modbus_TCP

ClientIP=(IP address of Modbus TCP devices)

ClientPort=(Port of Modbus TCP devices)  

Example:

[Platform]
Name=WISE-4012E
Protocol=Modbus_TCP
ClientIP=127.0.0.1
ClientPort=502

Interval=3
#Interval: The time interval of modbus data access/report cycle in second.
Delay=0
#Delay: The time delay between two modbus address R/W in millisecond.
#Delay=0 means no delay.
Log=0

[Devices]
numberOfDevices=2
Device0=Modbus_Device0.ini
Device1=Modbus_Device1.ini

Modbus RTU Connection:

Protocol=Modbus_RTU

SlavePort=(The serial port's device node of the Gateway which connect to Modbus RTU devices)

Baud=(The baud rate for the serial port to communicate with Modbus RTU device)

Parity=(The parity of the serial port)

DataBits=(The data bits of the serial port)              

StopBits=(The stop bits of the serial port) 

Example:

[Platform]
Name=EKI-XXXX
Protocol=Modbus_RTU
SlavePort=COM1
Baud=19200
Parity=None
DataBits=8
StopBits=1

Interval=3
#Interval: The time interval of modbus data access/report cycle in second.
Delay=0
#Delay: The time delay between two modbus address R/W in millisecond.
#Delay=0 means no delay.
Log=0

[Devices]
numberOfDevices=2
Device0=Modbus_Device0.ini
Device1=Modbus_Device1.ini

Config Modbus Devices & Sensors

1. DeviceInfo session:

    [DeviceInfo]

    UnitId: The UnitID is a device ID for a Modbus TCP device.

    SlaveID: The SlaveID is a device ID for a Modbus RTU device.

2. Coils session

    [Coils]

    NumberOfB: The number of Coils.

    Bn: The sensors definitation of Coils.

3. Discrete Inputs session

    [Discrete Inputs]

    NumberOfIB: The number of Descrete Inputs.

    IBn: The sensors definitation of Descrete Inputs.

4. Holding Registers session

    [Holding Registers]

    NumberOfR: The number of Holding Registers.

    Rn: The sensors definitation of Holding Registers.

5. Input Registers session

    [Input Registers]

    NumbrtOfIR: The number of Input Registers.

    IRn: The sensors definitation of Input Registers.

6. Coils Block session

    NumberOfBB: The number of Coils Block.

    BBn: The sensors definitation of Coils Block.

7. Discrete Input Block session

    NumberOfIBB: The number of Descrete Inputs Block.

    IBBn: The sensors definitation of Descrete Inputs Block.

8. Input Register Block session

    NumbrtOfIRB: The number of Input Registers Block.

    IRBn: The sensors definitation of Input Registers Block.

9. Holding Register session

    NumberOfRB: The number of Holding Registers Block.

    RBn: The sensors definitation of Holding Registers Block.

NOTE! The maximum length of sensor name is 30 characters.

Modbus_Device0.ini Example:

[DeviceInfo]
# For Modbus_TCP
UnitID=1
# For Modbus_RTU
#SlaveID=1

[Coils]
numberOfB=3
B0=0,LED0
B1=1,LED1
B2=2,LED2

Modbus_Device1.ini Example:

[DeviceInfo]
# For Modbus_TCP
UnitID=2
# For Modbus_RTU
#SlaveID=2

[Discrete Inputs]
numberOfIB=3
IB0=0,Switch0
IB1=1,Switch1
IB2=2,Switch2

[Input Registers]
numberOfIR=3
IR0=0,Data0,-1000000,1000000,1,V,0,""
IR1=1,Data1,-1000000,1000000,1,V,0,""
IR2=2,Data2,-1000000,1000000,1,V,0,""

Config Address and Data Types

The format and sensor address definition of sensors:

1. Single Data Format:

Tag = offset, name, min, max, precision, unit, data type, lua script

2. Block Data Format:

Block = offset, length, name

3. Tag's type, address and offset Mapping

Single Data:

Block Data:

4. min and max:

    The minimal and maximal range of the sensor.

5. Precision:

    The value to denormalize a normalized sensor value become a floating point number.

6. Unit:

    The unit for the sensor value.

7. The data type definition of sensors:

NOTE! For type of "32-bit unsigned int", the maximum support range in 0 ~ 2,147,483,647.

LUA Conversion

You can do a simple mathematic operation by add a forms in the LUA conversion string, for example:

Example1: To convert a 16-bit unsigned integer value to 16-bit signed value

[Holding Registers]
numberOfR=1
R0=0,Data0,-32768,32767,1,V,0,"(modbus_val>32767) and (modbus_val-65536) or modbus_val"

Example2: To do a mathematic forms operation.

[Holding Registers]
numberOfR=1
R0=0,Voltage0,0,5,0.001,V,0,"modbus_val*2-10"

NOTE: If both precision and LUA string are assigned, LUA string will be calculated with modbus value first, then the new value multiply with assigned precision.

LUA functions list:
https://www.kancloud.cn/thinkphp/lua-guide/43807

Docker version

To config Modbus Service and Restart Service in EdgeSense v1.0.2 Docker version:

$cd ${Installed path}/Installer/packages/Plugins/docker-edgesense-image-x86/EdgeSense/EService-Modbus/config
$sudo vim Modbus_Handler.ini
$sudo docker restart service-modbus

Real Application Case: ADAM-4117

Release

This is an overview that displays Modbus Service versions and some stats and numbers for each release.

Above files are available at local server, please paste file's url in File Explorer to copy file. (How to access to EOSSFS file server )