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:


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:


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

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

Released for:Schneider Electric Egypt and North East Africa