Our Brands

Welcome to the Schneider Electric Website

Welcome to our website.
		
How can we help you today?
How does one connect an HMI to Modicon M172 or M172 HVAC PLC for Modbus Serial communication?

Issue
How does one connect an HMI to Modicon M171 or M172 HVAC PLC for Modbus Serial communication?
What are the part numbers for the connectors on these PLCs?

Product Line
Modicon M171, M172 HVAC PLCs
EcoStruxure Machine Expert HVAC

Environment
Connectors for Serial communications

Resolution
The Serial connectors on Modicon M171 and M172 require a terminal block that have screw-type connectors for bare wire.
These kits are sold separately and are specific to the number of I/O pins on the corresponding model of PLC:

For the 14 I/O M171 or M172 model:
Part Number: TM171ASCTB14

For the 27I/O M171 or M172 model:
Part Number: TM171ASCTB27

The connectors attach to this port on the PLC:
physical connection

In order to connect an HMI, you would obtain the Serial Connector pinout diagram from the specific HMI's Hardware Manual, then wire the connectors accordingly.

See this example with the HMISTO715:
On the HMISTO715, the pinout is as follows:
pinout

So a cable with an RJ45 connector would have to be manually spliced from:

HMI                         M171/M172
4 D1  -----------------   “+”
5 D0 ------------------   “-“
8 SG ------------------   “GS”

If this FAQ did not solve your issue, you can chat with us at chat with us or e-mail us at customer.services@se.com to create a case with our Technical Support Team.

If you are not located in North America, please contact your local Customer Care Center for assistance:

Support | Schneider Electric Global (se.com)

Schneider Electric Hong Kong

Explore more
Range:
Users group

Discuss this topic with experts

Visit our Community for first-hand insights from experts and peers on this topic and more.
Explore more
Range:

Need help?

  • Start here!

    Find answers now. Search for a solution on your own, or connect with one of our experts.

  • Contact Support

    Reach out to our customer care team to receive more information, technical support, assistance with complaints and more.

  • Where to buy?

    Easily find the nearest Schneider Electric distributor in your location.

  • Search FAQs

    Search topic-related frequently asked questions to find answers you need.

  • Contact Sales

    Start your sales enquiry online and an expert will connect with you.

I'd like to receive news and commercial info from Schneider Electric and its affiliates via electronic communication means such as email, and I agree to the collection of information on the opening and clicks on these emails (using invisible pixels in the images), to measure performance of Schneider Electric's communications and to improve them. For more details, please read our Privacy Policy.

  • Products Documentation
  • Software Downloads
  • Product Selector
  • Product Substitution and Replacement
  • Help and Contact centre
  • Find our Offices
  • Get a Quote
  • Where to buy
  • Careers
  • Company Profile
  • Report a misconduct
  • Accessibility
  • Newsroom
  • Investors
  • EcoStruxure
  • Job Search
  • Blog
  • Privacy Policy
  • Cookie Notice
  • Terms of use
  • Change your cookie settings
Your browser is out of date and has known security issues.

It also may not display all features of this website or other websites.

Please upgrade your browser to access all of the features of this website.

Latest version for Google Chrome, Mozilla Firefox or Microsoft Edgeis recommended for optimal functionality.