Revision as of 09:00, 27 November 2018

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 ata 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

1. Double click Agent_Modbus_Handler_2.0.0.exe 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.

For the modbus TCP devices:

Protocol=Modbus_TCP

ClientIP=(IP address of Modbus TCP devices)

ClientPort=(Port of Modbus TCP devices)  

Modbus_Handler.ini 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

For the modbus RTU devices:

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

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,""

The format and sensor address definition of sensors:

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

tag Type Base Address

B 00001-->Coils

IB 10001-->Discrete Inputs

IR 30001-->Input Registers

R 40001-->Holding Registers

The data type definition of sensors:

0->16-bit operation

1->32-bit float no swap

2->32-bit float byte and word swap

3->32-bit float byte swap

4->32-bit float word swap

5->32-bit unsigned int no swap

6->32-bit unsigned int word swap

7->32-bit signed int no swap

8->32-bit signed int word swap

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,To_Signed_by_LUA,-1000000,1000000,1,V,0,"(modbus_val>32767) and (modbus_val-65536) or modbus_val"

Example2: To do a mathematic forms operation.

[Holding Registers]
numberOfR=2
R0=0,Voltage0,0,5,0.001,V,0,"modbus_val*2-10"<br/>R1=1,Voltage1,0,5,0.001,V,0,"math.pow(modbus_val,1/2)+10-2.5"

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.