Panel firmware travels inside the programming-software installer; the PLC needs two downloads, the update tool and the exact firmware binary for the installed CPU model. A program change normally needs no PLC firmware update at all. Verify every file opens offline before you leave.
Servicing a machine that pairs an HMI panel with a PLC at a site with no internet is a packing problem before it is a repair. Everything the visit needs has to be on your laptop and a USB stick before you leave, because there is no second trip for a forgotten binary. Panel firmware travels inside its programming-software installer. PLC firmware is two separate downloads, the update tool and the exact binary for the installed CPU model. This checklist walks through what to identify, what to download, and what to do on site in what order.
One package for the panel, two files for the PLC
The two devices take updates in different ways, and packing as if they were the same is the classic failed visit.
For the HMI panel, the firmware normally ships inside the programming-software installer. When you download a project, the software recognizes that the panel's firmware is older than the version the project expects and offers the update at that moment. One complete installer therefore covers both the programming and the firmware update. Confirm the arrangement in the panel's manual for your model before you travel.
For the PLC, firmware is never bundled. The maker's firmware download page hosts two separate downloads: an update tool, and the firmware binary for each CPU model. For one maker's DL-series CPUs, the update tool covers the DL05, DL06 and D2-250 CPUs, and the firmware binaries for each model are downloaded separately from the same page. The tool alone is not enough; the binary supplies the actual code the tool writes to the PLC, which is why both files go on the stick.
Identify the hardware before you pack
Write these down before you download anything. A wrong model number produces a wrong binary, and a wrong binary produces a dead visit.
- The exact PLC CPU model, read off the printer label on the module. Firmware binaries are listed per exact model, so record the full model designation such as DL06, plus any hardware revision shown on the label.
- The panel model and its installed firmware version. Reading the installed HMI panel firmware version for field maintenance shows where panels report it.
- The version of the programming software installed at your shop, because the project format and the bundled panel firmware both belong to a release.
- The project files for this machine: the panel project and the PLC program, plus the last known-good backup of each.
- The programming cable for the exact CPU, not a generic serial lead. Connectors and signal assignments differ between PLC families and even between models, as a note on choosing a PLC cable by exact CPU model shows.
- The communication settings that worked last time: node address, baud rate, protocol.
Download these files before you leave
- The full programming-software installer for the panel, with its files kept together. Firmware packaging changes between software releases; some HMI platforms record that updating an HMI operating system separately from its runtime software only became possible at a late service-pack release of the tooling, so an installer and its bundled firmware belong together.
- The PLC firmware update tool, from the maker's firmware page.
- One firmware binary per installed PLC model, from the same page. For a machine with one DL06 CPU, that is one binary.
- The panel project and the PLC program you intend to load, and the last known-good backups.
- Two copies of every file, one set on the laptop and one on the USB stick.
Media size is a non-issue: one vendor's complete firmware upgrade tool set downloads as a 51.9 MB ZIP, so a 1 GB stick holds every installer, tool, binary and backup a two-device visit will ever need. The part people forget is the offline check. Install the software on the travel laptop, open each project, and confirm the tool and the binary launch before you lock the shop door.
Scenario: a dispenser untouched for five years
The machine is a benchtop color dispenser run by a DL06 CPU and a small graphic HMI panel. The last visit was five years ago, the site has no internet, and the job is a program fix.
Packing arithmetic:
- Panel: 1 programming-software installer, firmware bundled.
- PLC: 1 update tool + 1 DL06 firmware binary = 2 files.
- Intended loads: 1 panel project + 1 PLC program = 2 files.
- Backups: 2 devices x 2 copies = 4 files.
Total: 1 + 2 + 2 + 4 = 9 files on one USB stick, a few dozen megabytes in all.
On site, the panel download triggers a firmware prompt and you accept one update. The DL06 accepts the program download with no firmware change, so the tool and the binary stay in the bag. The decision: pack the two PLC firmware files even for a program-only job at an offline site. They cost nothing until run, and they are mandatory the day a documented bug fix or a replaced CPU turns the job into a firmware update.
On site, in order
Work in this order and keep each operation separate.
- Back up before you write. Upload the PLC program and read the panel project, and save both to the laptop and the stick. If the panel will not open its project over the cable, restoring an HMI project from a USB drive without programming software covers the hand-off path.
- Download the panel project. If the software reports that panel firmware must be updated, check that the prompt names your exact panel model, then accept it and let it finish.
- Never remove power or pull the cable during a firmware write. A half-written panel may not restart its firmware loader, and there is no fix for that at a site with no internet.
- Download the PLC program first and exercise the machine's function under a safe test condition. Run the PLC firmware update only when a documented bug fix or a hardware-compatibility requirement calls for one, using the tool and the binary that match the installed model.
- Read the firmware and software versions back after each operation and record them; verifying the installed HMI software version after an upgrade shows the check.
The decision
- Program change only, PLC healthy: bring the programming software, the project and the backups. No PLC firmware files are required for the job, and the installed firmware stays untouched.
- Documented bug fix or new-hardware compatibility on the PLC: bring the update tool and the exact firmware binary, both of them. One without the other is an incomplete kit.
- Panel firmware prompt on download: accept the update the bundled installer offers, after checking the target model in the prompt.
- Site with no internet: pack the tool and the binary even for a program-only job, since the files cost nothing until run and cover the case you did not expect.
Recommendation: For any visit to a site with no internet, install the panel programming software on the travel laptop, copy the PLC maker's update tool plus one firmware binary per installed CPU, and carry two copies of every project and backup before you leave the shop. Run a PLC firmware update only for a documented bug fix or hardware-compatibility need, let the panel software's own download-time prompt handle panel firmware, and keep every firmware write on its own uninterrupted power and cable.
Leave a record for the next visit
- Final firmware and software revisions for both devices.
- What changed, one line per operation: program, panel firmware, PLC firmware.
- Which backup file matches the running machine.
- The settings that worked: node address, baud rate, cable used.
A five-year gap is hard to reconstruct from memory. A card in the panel's cabinet door with the revisions and the file names turns the next visit into an hour instead of a day.
Questions
How do I find the installed firmware versions before the visit?
Read the PLC CPU model and any hardware revision from the label on the module, and read the panel's firmware version from its setup or diagnostics screens or from the programming software's connection dialog. Write the versions down with the exact model designations. If the panel will not connect from your shop, the label and the last service report still identify which binary to download. Packing by memory is how the wrong binary ends up on the stick.
What should I do if a firmware update stops part way?
Note the exact error text and leave the device powered and cabled as it is. Repeat the same documented procedure with the same tool and the same binary, and check that the binary matches the exact model before the second attempt. If the device will not restart after that, the maker's support channel documents the recovery for that model, which is a reason to carry the manufacturer's contact details on paper on a no-internet visit.
Can I update the panel and the PLC firmware in the same session?
Yes, but as two separate operations with a working communication check between them. Finish and verify the panel download, confirm the panel talks to the PLC, and only then start the PLC firmware update with its own tool and binary. One change per step means a fault points at the change that introduced it, and the record you leave behind states which operation touched which device.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.