The MPS050A020 has no Ethernet port, so send LogicLab programming traffic to it through the serial connection or through USB after the PC creates an RNDIS network interface. Keep the physical connection, PC-side interface, and controller endpoint distinct when diagnosing where communication stops.
How does a programming request reach the MPS050A020?
A download begins at the PC in LogicLab and crosses one of two paths. The serial path carries the request over a serial cable to the controller. The USB path first creates an RNDIS network interface on the PC; LogicLab then reaches the controller over that USB-backed network connection. The controller is the destination in either case.
There is no third path through a built-in Ethernet port on this model. If a connection attempt is aimed at an Ethernet jack or an Ethernet address assigned to some other adapter, the request will not reach the MPS050A020. Confirm the cable and selected PC interface before investigating LogicLab settings or the project.
| Path | Physical connection | PC-side requirement | Controller endpoint |
|---|---|---|---|
| Serial | Serial connection to the PC | Configure the serial link at 115200, E, 8, 1 | Controller on that serial link |
| USB | USB connection | RNDIS network driver/interface, PC IP 192.168.1.10 | Module IP 192.168.1.122 |
The documented USB addresses identify the two ends of the programming path: the PC uses 192.168.1.10 and the module uses 192.168.1.122. They are not instructions to configure a physical Ethernet port on the controller. Do not substitute a different PC network interface without first checking which adapter LogicLab will use to reach the module.
Does the unit provide an Ethernet port?
Read the model marking on the hardware. For the MPS050A020 in this case, the answer is no; use the serial or USB route. The MPS050B020 is described as the same product with some upgrade, but that does not establish that the A and B models have identical hardware details. Check the exact unit and its documentation rather than transferring a connection assumption from one suffix to another.
- Read the complete model code on the controller.
- If it is MPS050A020, rule out direct Ethernet as the programming path.
- Choose serial when you can connect and configure the serial interface, or choose USB when the PC creates the RNDIS interface.
- Continue with the matching connection checks below; do not troubleshoot both paths as though they were one interface.
This decision separates a hardware limitation from a network fault. A failed Ethernet attempt on an MPS050A020 is not evidence of a bad project or failed firmware; the required physical interface is absent.
Does the serial link use the specified settings?
For serial programming, set the PC connection to 115200, E, 8, 1, then select that serial connection in the programming workflow. The sequence gives the baud rate and the remaining serial format values. A mismatch at this layer can prevent the PC and controller from exchanging a usable programming request even when the cable is attached.
| Setting | Required value | Check |
|---|---|---|
| Baud rate | 115200 | Match the PC-side serial configuration to the stated rate |
| Parity notation | E | Use the E selection shown by the serial configuration interface |
| Data bits | 8 | Match the stated value |
| Stop bits | 1 | Match the stated value |
If LogicLab cannot communicate over serial, first confirm that the selected port is the one connected to the controller and that every listed setting matches. If the link still fails, test the USB RNDIS route as a separate path; success or failure on one route does not prove the other route is configured correctly.
Does USB create the RNDIS route to the module?
Connect the controller to the PC over USB and check that the connection creates an RNDIS network driver/interface on the PC. Configure that PC-side interface with 192.168.1.10, then direct the programming connection to the module at 192.168.1.122. The USB cable is the physical hop; RNDIS provides the network interface used over it.
| Endpoint | Address | Diagnostic reading |
|---|---|---|
| PC RNDIS interface | 192.168.1.10 | Confirm the address is assigned to the USB-created interface |
| SlimLine module | 192.168.1.122 | Use this as the target module address |
If the RNDIS interface does not appear, investigate USB detection and the PC driver before changing the controller target address. If the interface is present but the PC address is wrong, correct the PC-side setting. If both readings match and LogicLab still cannot connect, confirm LogicLab is using this USB-backed route and that the physical USB connection remains active. Do not try to solve an RNDIS issue by looking for an Ethernet port on the MPS050A020.
Is the firmware update path prepared correctly?
The programming guidance calls for updating the controller to the latest XUnified firmware by connecting it to the PC over serial and using Toolly. It explicitly says not to perform a bootloader upgrade. Treat the firmware update and bootloader update as separate operations: the instruction is to update firmware, not to select every available upgrade option.
- Identify the controller as MPS050A020 before selecting an update package.
- Connect the controller to the PC through serial and configure the serial link at 115200, E, 8, 1.
- Use Toolly to perform the XUnified firmware update specified for the unit.
- Do not execute the bootloader update.
- After the firmware operation, reconnect through the intended LogicLab programming path and test communication before proceeding to a project download.
Firmware packages and instructions can change over time. Obtain the applicable XUnified package and procedure from the product documentation or the manufacturer’s current download location; do not infer a package version from the model alone. If the update fails, keep the firmware-update connection and the later LogicLab project connection separate during diagnosis. A successful serial update confirms the update path, not the USB RNDIS route.
Can LogicLab test the project without the controller?
LogicLab is the programming environment, and SimuLab is its PC simulator. Use SimuLab to test program behavior without connecting the MPS050A020, but do not treat a successful simulation as proof of hardware communications: simulation on the PC does not manage serial or Ethernet communications.
That limitation matters when a simulated program works but a live test does not. Simulation can help isolate program logic from controller connectivity, while the physical serial or USB path must still be tested on the actual unit. Because this model lacks an Ethernet port, the live communication options described here remain serial and USB/RNDIS.
LogicLab’s installation includes an Examples folder containing sample programs identified with codes in the Ptpxxx form. Use these as starting points for exploring the programming environment. The Knowledge Base also documents supplied functions and function blocks in LogicLab libraries, with one or more ST example programs for each object. Examples are identified with the Ptpxxx program in which they reside.
Which example should you import into a project?
When a Knowledge Base example is written in ST, import it into the project to inspect or reuse the function or function-block example. Then locate its associated Ptpxxx program in the Examples collection. That program may contain related examples in IL, LD, or FBD; use LogicLab’s Import command to bring a relevant example into the project.
- Find the library function or function block in the Knowledge Base and note its ST example.
- Identify the associated Ptpxxx program named with the example.
- Open that program’s related logic and select an IL, LD, or FBD example when that language is useful for the lesson.
- Use LogicLab’s Import command to add the selected sample to the project, then inspect its inputs, outputs, and execution context before adapting it.
- Test logic in SimuLab where appropriate, then connect to the controller using serial or USB/RNDIS for hardware communication checks.
Keep the distinction clear: imported code can be examined and simulated on the PC, but live communication and behavior on the MPS050A020 require a working physical connection.
FAQ
Why does LogicLab not find an Ethernet connection on an MPS050A020?
The MPS050A020 does not have an Ethernet port. Connect by serial at 115200, E, 8, 1, or use USB after the PC creates the RNDIS interface.
Why does the USB-connected SlimLine not appear on the network?
USB must create an RNDIS network interface on the PC. Check that interface first, assign the PC address 192.168.1.10, and use 192.168.1.122 as the module address.
Why can SimuLab run a program but not test communication?
SimuLab runs on the PC and does not manage serial or Ethernet communications. Use simulation to test program logic, then test the communication path with the connected controller.
Why should I avoid a bootloader update?
The specified update procedure calls for XUnified firmware using Toolly over serial and explicitly says not to execute the bootloader update. Select the firmware operation only.
How do I verify the MPS050A020 programming connection?
For serial, confirm the selected connected port and 115200, E, 8, 1; for USB, confirm the RNDIS interface has PC address 192.168.1.10 and the module target is 192.168.1.122. Then make a LogicLab connection to the controller using that same path.