A DOP-B07S415 HMI can read process and setpoint values directly from temperature controllers without modifying the existing SA2 PLC program. Configure an unused HMI serial port as a Modbus RTU master, then connect both controllers to the same RS-485 network with unique station addresses.
Required Communication Information
Obtain the Modbus RTU communication settings, station-address procedure, and register map from the temperature-controller documentation. The evidence identifies the required values as PV and SV; the request calls the setpoint SP, so confirm whether the controller documentation labels that register SV or SP before creating HMI objects.
| Item | Required decision |
|---|---|
| HMI port | Use an available port and configure it for Modbus RTU. |
| Physical layer | Connect the controllers through RS-485. |
| Station addresses | Assign a different address to each controller. |
| PV register | Obtain the exact address and data format from the controller register map. |
| SV/SP register | Confirm the terminology, address, data format, and whether writing is permitted. |
| Serial settings | Match the HMI and both controllers using the documented Modbus RTU settings. |
Configure Both Controllers on One RS-485 Port
- Confirm that an HMI serial port is unused by the existing PLC connection.
- Configure that port as a Modbus RTU master.
- Connect both temperature controllers to the same RS-485 network.
- Assign a unique Modbus station address to each controller.
- Create HMI tags or display objects for each controller's PV and SV/SP registers, using the correct station address for each device.
- Verify that each displayed value follows the corresponding controller and that the two devices are not being confused.
This arrangement keeps temperature-data acquisition separate from the PLC application. Do not alter the working HMI-to-PLC port when a spare HMI port is available.
Resolve the AC911 and AC991 Model Ambiguity
The request identifies the controllers as AC911, but the available model-specific warning refers to AC991 hardware. It states that AC991-03-00-1110 supports the required communication hardware, while AC991-03-00-0010 cannot communicate. Do not apply that suffix rule to an AC911 without confirming the exact nameplate model and its Modbus capability.
An external RS-485 connector alone does not prove that the internal electronics implement communication. Before troubleshooting HMI addresses, verify the complete controller model and confirm that its installed electronics support Modbus RTU.
Record Hourly Values on the HMI
The described HMI workflow does not provide a reporting function, but it can record data once per hour and display the stored values in a data-record table. Configure data logging for the required PV and SV/SP tags, select an hourly logging interval, and add a data table for reviewing the accumulated records at the end of the day.
Verify the result by allowing at least one logging interval to complete and checking that each controller produces a separate timestamped record. This provides historical viewing on the HMI; it does not establish automatic daily report generation.
FAQ
Can two temperature controllers share one DOP-B07S415 RS-485 port?
Yes. Connect both to the same RS-485 port and assign a different Modbus station address to each controller.
Can the HMI read PV and SP without changing the PLC program?
Yes, if an unused HMI port is configured for Modbus RTU and the controller supports communication. Obtain the exact PV and SV/SP register addresses before configuring the HMI tags.
Can the DOP-B07S415 save temperature values every hour?
It can log the selected data once per hour and show the records in a data table. The evidence does not establish a report-generation function, so treat logging and on-screen review as the supported workflow.