Adding a New PLC Connection
This section describes the procedure for registering a single PLC to the gateway.
Before You Begin
You'll need the following information. It's faster if you write it down beforehand.
| Item | Where to find it |
|---|---|
| PLC IP address | PLC body label, network settings screen, or your company's network administrator |
| PLC communication port | Defaults vary by PLC type. See the PLC Type Guide in this manual |
| Communication availability | ping <PLC IP> must respond from the gateway PC |
The PLC must be on the same network segment (VLAN) as the gateway for communication to work. If it's on a different segment, routing or firewall settings are required.
Procedure
1. Click the [Connection] menu
Click the [Connection] menu at the top of the gateway screen.
2. Click the [Add Connection] button
Press the blue [Add Connection] button above the [Connection List].
3. Select the protocol (PLC type)
On the "Select the PLC or protocol to register" screen, click the card that matches your PLC.
- If you're not sure which card to choose, see the PLC Type Comparison Table.
- If you're in a test environment without a PLC, you can select the Simulator card.
4. Fill out the registration form
The form layout varies slightly by PLC type. The common fields are as follows:
| Input Field | Description | Recommended Value / Example |
|---|---|---|
| Connection ID | Unique code within the gateway to identify this PLC | OPC_LINE1 (alphanumeric/underscore, spaces and Korean characters not recommended) |
| Connection Name | Name displayed on the screen | 1라인 미쓰비시 PLC |
| IP Address | PLC network address | 192.168.0.60 |
| Port | PLC communication port | (varies by PLC type) |
| Site ID | Site code (auto-filled) | (leave as is) |
| Collection interval (ms) | How often to read values in milliseconds | 1000 (1 second). 500 for rapidly changing values, 5000 for slow-changing values |
| Start collection automatically | Whether to bring this connection to START automatically when the gateway (collector) starts. If off, it will remain stopped after startup | Recommended to leave on for operational use |
Additional options specific to each PLC type (username/password, series type, etc.) are explained in detail on the respective pages of the PLC Type Guide.
5. Add tags (which values to read)
In the [Tags] section at the bottom of the same form, add the values to be read one line at a time.
- You can [Add] / [Delete] rows.
- You can also register just the PLC with zero tags (they can be added later).
Tag input fields and address notation are covered in detail on the Tag Registration page.
6. Click [Save]
When you click [Save], the following happens automatically:
- The gateway attempts to connect to the PLC.
- It begins automatically reading the registered tags at the collection interval.
- It exports the values to the configured transmission channels, such as the PlantPulse platform / MQTT.
Please wait a moment. The first values usually arrive within 1 to 3 seconds.
Post-Registration Verification
Return to the [Connection List] screen and you'll see the registered PLC. It auto-refreshes every 5 seconds.
Each card displays two separate statuses — this is a common point of confusion.
① Collection status — the text badge on the left side of the card
| Badge | Meaning | Next action |
|---|---|---|
| Green Normal | Values are being received | Click the card to see current values per tag |
| Yellow Abnormal | Collection is happening but there's a problem | Check the last error message in the card details |
| Gray Stopped | Polling has stopped | Start it with the ▶ button on the card |
② Connection status — the icon on the right side of the card (no text; it appears on hover)
| Icon | Tooltip | Meaning |
|---|---|---|
| Green Wi-Fi | Connected | The PLC is reachable |
| Red Wi-Fi (slashed) | Disconnected | The PLC is not reachable → Connection Issues |
| Gray Question Mark | Unknown | No status has been reported yet |
There actually is a state where it's connected but no values are coming — the icon is green but the badge is Stopped, or both are green but tag values are empty. Where to look depends on which case it is → Values Not Arriving
The summary line at the top of the screen counts the same things as Stopped · Connected · Disconnected — the badge's 「Stopped」 and the summary's 「Stopped」 are the same state.
Common Follow-up Tasks
| Task | How to do it |
|---|---|
| Modify PLC information | [Edit] button on the left row → the form reopens |
| Delete PLC | [Delete] button on the left row. Registered tags are also deleted (with a confirmation popup) |
| Pause collection | [Stop] button on the right of the row |
| Resume collection | [Start] button on the right of the row |
| Add a single tag | Click the PLC row, then the [Add Tag] button above the [Tags] table |
Registering Multiple Items at Once (CSV Batch Upload)
If you have dozens or hundreds of tags, entering them line by line is tedious. You can use the [CSV Batch Upload] button at the top right of the [Connection] menu to register them all at once using an Excel-format file.
The CSV format and sample files are documented on the upload screen.
Frequently Asked Questions
Q. Can't the Connection ID be in Korean?
Please use only English letters, numbers, and underscores (_). As this is an internal system identifier, Korean characters or spaces can cause problems in other screens or with external integrations.
Q. Can I register two PLCs with the same IP address?
Technically, yes. However, the Connection IDs must be different. This is useful when you want to manage different areas of the same PLC separately (for example, a Mitsubishi PLC with D and R areas).
Q. What happens if I set the collection interval too short (e.g., 100ms)?
The PLC may not be able to handle it, or the gateway resources may be insufficient. Generally, 500ms ~ 1000ms is a safe range. Only use shorter intervals if you truly need very fast values.
Q. Where do I enter the PLC password?
Only protocols that use username/password authentication, such as OPC-UA, have a password field in the form. Standard PLCs (Modbus / Mitsubishi / Siemens / LS) don't have a password concept and anyone with the IP address can connect (please be mindful of your internal network security).