MODULE DETAILS

 

Module 8: MODBUS

 

Nominal duration: 2 weeks (16 hours total time commitment).

 

This time commitment includes the preparation reading, attendance at each webinar (1 hour plus 15-30 minutes for discussion), and the time necessary to complete the assignments and further study

 

MODULE PURPOSE

 

MODBUS is one of the few industrial messaging protocols recognized by the Internet (TCP/IP) world, and has been assigned ‘well-known’ TCP port number 502. It has one of the largest installed bases world-wide, with more than 7 million installed nodes. The MODBUS/TCP profile has been accepted by the International Electro-technical Commission (IEC) as a Publicly Available Specification (IEC PAS 62030), which made it eligible to become part of the International Standards IEC 61158 and IEC 61784-2. It enjoys the status of an open standard, available to everyone, hence its popularity.

 

PRE-REQUISITE MODULES, UNITS

/CO-REQUISITES

 

Module 3: Ethernet; Module 5: TCP/IP and VoIP

 

ASSESSMENT STRATEGY

 

To evaluate the achievement of the learning outcomes; written assignments, group projects and practical exercises are set.

 

SUMMARY OF LEARNING OUTCOMES

 

1.      Examine and discuss MODBUS Serial

 

2.      Examine and discuss MODBUS over TCP/IP

 

 



Learning Outcome 1

 

Examine and discuss MODBUS Serial

 

Assessment Criteria

 

1.1 Examine and discuss Modbus RTU in terms of:

       (a)   Protocol stack

       (b)   Function Codes

       (c)   Absolute and relative addressing

       (d)   Master-slave (client-server) interaction

       (e)   Message structure (PDU and ADU)

       (f)    Error messages

 

 

1.2 Compare MODBUS RTU and MODBUS ASCII

 

 

 

 

 

Learning Outcome 2

 

Examine and discuss MODBUS over TCP/IP

 

Assessment Criteria

 

2.1   Explain how MODBUS handles 32-bit and 64-bit numbers

 

2.2   Examine and discuss the operation of MODBUS RTU over TCP

 

2.3   Examine and discuss the operation of MODBUS/TCP

 

2.4   Use a gateway to communicate between MODBUS/TCP and MODBUS/RTU nodes

 

 

Delivery mode

A combination of asynchronous and synchronous e-learning delivery comprising a judicious mix of interactive online web conferencing, simulation (virtual labs) software, remote online labs, online videos, PowerPoint slides, notes, reading and study materials (in PDF, HTML and Word format) accessed through the Moodle Learning Management System (LMS).

 

Software/Hardware Used

Software

  • Modbus Poll

  • Modbus Slave 
  • SetupVSPE
  • Virtual Serial Port Emulator
  • Wireshark

Hardware

  •  N/A