Troubleshooting
This guide is organized by symptom so you can find and fix problems quickly.
If systemctl is-active plantpulse-edge.service is active, you are in container mode — for some symptoms, the "Fault Response" section of the
Container Mode Operations Guide or the scenario matrix (A–E) in /opt/kopens/install/RUNBOOK.md inside the box
provides a faster diagnosis. To collect diagnostic information all at once:
sudo bash /opt/kopens/install/bin/doctor.sh
# → /tmp/pe-doctor-`<host>`-`<ts>`.tar.zst (support 전달)
Quick Index
| Symptom | Where to go |
|---|---|
| The gateway screen won't open | The screen won't open |
| I can't log in | I can't log in |
| The connection fails (PLC) | The connection fails |
| It connects, but no values arrive | No values are arriving |
| Values arrive, but they look wrong | The values look wrong |
| Values suddenly stopped arriving | Values stopped suddenly |
| The screen is slow | The screen is slow |
| Memory/disk gauges are red | Resources are running low |
| Data isn't being sent to the cloud / SCADA | Transmission fails |
| Tag [Write] doesn't work | I can't write a value |
The screen won't open
You entered the gateway IP in your browser, but the page doesn't load.
Step 1 — Check whether the gateway is reachable from your PC
At the command prompt:
ping <gateway-ip>
If there is no response, it's a network / cable / VPN issue. Tell your system administrator that "the gateway is unreachable."
Step 2 — Try another browser / user
If the same symptom occurs on another PC, the gateway itself may be shut down or hung. Your system administrator will need to reboot the gateway PC.
Step 3 — Check the URL
http://게이트웨이IP/is the usual format.- In some cases a port number is included as well (e.g.
http://게이트웨이IP:8080/). - If you don't know your site's standard URL, check with a colleague.
I can't log in
I forgot the password
Try the default password.
- ID:
admin - Password:
admin123!
If the credentials have already been changed, ask your system administrator to reset the password.
I get kicked out right after logging in
This may be a session / cookie problem. Clear your browser cookies and try again.
The connection fails
A red "Connection Failed" is shown on the [Connections] screen.
Step 1 — Is the PLC reachable from the same PC?
Ask your system administrator to confirm that the gateway PC can ping the PLC IP.
Step 2 — Is the port correct?
Default ports by PLC type:
| PLC | Port |
|---|---|
| OPC-UA (Kepware) | 49320 |
| Modbus TCP | 502 |
| Mitsubishi (Q/L) | 5000 or 1029 (per PLC setting) |
| Mitsubishi (iQ-R) | 1500 |
| Siemens S7 | 102 |
| LS | 2004 |
| AB EtherNet/IP | 44818 |
The communication module on the PLC side must be enabled.
Step 3 — PLC-side security settings
| PLC | Additional setup required |
|---|---|
| Siemens S7 | Enable "Permit PUT/GET communication" in TIA Portal + turn OFF Optimized mode for the DB |
| Mitsubishi | Enable "MC protocol / TCP / port" in GX Works |
| OPC-UA | Allow user/password or anonymous access |
| LS | ICMP (ping) must not be blocked |
Step 4 — User / password
For PLCs with authentication such as OPC-UA, the ID / password must be exactly right. Re-enter them in the PLC [Edit] form and try again.
No values are arriving
The connection shows "Connected," but the [Current Value] field of the tag is empty.
Step 1 — Check the PLC address notation
This is the most common cause. Notation differs by PLC type.
- Mitsubishi:
D100,M50(no%prefix) - Siemens:
%DB1.DBW0(with%prefix, DB number + DBW/DBD) - LS:
D00309(5-digit number) - OPC-UA:
ns=2;s=경로format
Re-check the [PLC Address Notation] section on the page for your PLC.
Step 2 — Check the data type / format modifier
If the value is 32-bit or larger but [Format Modifier] is empty, it may be read incorrectly as 16-bit and the value won't appear.
- 32-bit integer: format modifier =
DW - 32-bit float: format modifier =
REAL - 64-bit float: format modifier =
LREAL
Step 3 — Verify the same address with another tool
Check in the monitor / watch window of the PLC engineering tool (GX Works / TIA Portal / XG5000 / UA Expert) that the same address actually works.
The values look wrong
Values do arrive, but the numbers are far too large or too small, or the sign is inverted.
A 32-bit value is being read as 16-bit
The values look random, or one half appears truncated. Specify DW (integer) or REAL (float) in [Format Modifier].
An unsigned value is being read as signed
For example, 65535 appears as -1. Specify UI (16-bit unsigned) or UDW (32-bit unsigned) in [Format Modifier].
The byte / word order (endianness) is reversed
If a particular slave (common with Modbus slaves) sends values in little-endian, 32-bit floats appear corrupted.
- For Modbus, try a data type variant such as
:UDINT_LSWORD_FIRST - For other PLCs, post-processing via Apply Formula is sometimes not feasible — contact your system administrator
The unit is different
The PLC sends a raw integer value (e.g. 1638) whose actual meaning is something like 163.8. Use Apply Formula and enter ${VALUE}*0.1 to convert the unit.
Values stopped suddenly
Values were arriving fine, then stopped at some point.
Step 1 — Check the connection status
What is the connection status of that PLC in the [Connections] menu?
| Status | Meaning / next action |
|---|---|
| Red "Connection Failed" | Problem on the PLC side. Reboot the PLC or inspect the cable / network |
| Gray "Stopped" | Someone pressed [Stop], or it stopped automatically. Resume with the [Start] button |
| Green "Connected" + no values | The address on the PLC may have been disabled |
Step 2 — Inspect the PLC itself
- Is the PLC in RUN mode? (Values stop if it has dropped to STOP)
- Have the memory protection settings for that address area changed?
- If a PLC firmware update / reboot has just occurred, wait a moment and it will reconnect automatically
Step 3 — Restart the gateway
Use [Settings] → [Restart Application] to bring the gateway back up. Recovery takes under 1 minute.
The screen is slow
When there are a great many PLCs or tags, the initial load may be delayed by 1–2 seconds.
- This is usually not a problem.
- If the CPU gauge on the main screen is red, the gateway PC may be short on resources. Contact your system administrator.
Resources are running low
The CPU / memory / disk gauges on the main screen are shown in red.
| Gauge | Action |
|---|---|
| CPU | Check whether any PLC uses an overly short collection period. Increase it to 1 second or more |
| Memory | [Settings] → [Restart Application] gives temporary relief. If it recurs, ask your system administrator to add memory |
| Disk | [Settings] → [Clean Temporary Files]. The time series retention period may also be too long |
Transmission fails
Values are collected fine, but they aren't delivered to the cloud / SCADA / MQTT.
MQTT / Sparkplug not publishing
- Ask your system administrator to verify that MQTT is enabled
- Check that the MQTT broker (HiveMQ, etc.) is running on the same gateway PC
No response from the Platform API
- If the PlantPulse Platform itself is unreachable → contact headquarters / the operations team
- The gateway queues the data locally, so brief outages recover automatically.
For log keywords and log locations intended for system administrators, see Advanced — Developer Notes.
Last resort
- [Settings] → [Download Logs] to download all diagnostic logs at once
- [Settings] → [Restart Application] to restart only the gateway (1 minute)
- [Settings] → [System Reboot] to reboot the PC itself (3–5 minutes)
If the problem persists, attach the downloaded logs and contact KOPENS or the PlantPulse operations team.
I can't write a value
You clicked the [Write] icon at the end of a tag row and got a message such as "Write failed" / "driver returned false."
Write support by protocol
Write support differs by PLC type.
| Your PLC | Write support | Notes |
|---|---|---|
| Mitsubishi (MELSEC) | ✅ Supported | Q/L/iQ-R all supported |
| Siemens (S7) | ✅ Supported | DB/M/I/Q areas |
| OPC-UA (Kepware, etc.) | ✅ Supported | Write permission on the target node required |
| Modbus TCP | ✅ Supported | Holding Register / Coil |
| HTTP push | ✅ Supported (cached) | — |
| LS ELECTRIC (XGI/XBC/XBM) | ✅ Supported | Bit/Byte/Word/DWord/Float/Double |
| AB EtherNet/IP | ✅ Supported | Some types may be rejected depending on PLC firmware/patch level |
Common messages
| Message | Meaning / action |
|---|---|
쓰기 실패 (opc_type=...) | The driver returned false. Check the address format, data type (format), and Write permission on the PLC |
tag not found: ... | Invalid tag ID. Refresh and try again |
scheduler not running for opc_id=... | That PLC is in [Stopped] state. Press [Start] and retry |
OPC ... 가 PLC 와 연결되어 있지 않습니다 | A write was attempted in DISCONNECTED state — check IP/port/firewall and restart |
If it still doesn't work
- Give your system administrator [PLC type + tag ID + the full message].
- The gateway log provides a more detailed cause.