Activity LED
The TCP/IP-based monitoring devices are equipped with several LED status lights on the front panel. We will now explain the function of these status messages.
Activity indicator
Description: appliance status
For all Didactum Units.
| LED | Color | Mode | Function (Percentage Indication) |
|---|---|---|---|
| ACT / Activity | Green | Normal mode | The LED is active (ON) 50 % of the time, inactive (OFF) 50 % of the time. |
| Recovery mode | The LED is active 25 % of the time per cycle, inactive 75 % - fast blinking. | ||
| Error, stuck | The LED remains at 100 % ON or 0 % (OFF) - indicating a device freeze or boot failure. |
Error LED
Description: errors and activity.
For all Didactum Units.
| LED | Color | Mode | Function (Percentage Indication) |
|---|---|---|---|
| ERR / Error | Red | Normal mode | 0 % activity (OFF) — no error. 100 % ON (constant glow) — error present. |
| One-time activity | Brief 100 % ON pulse (single flash, approx. 0.1–0.5 sec) for restart of failed service or USB backup. | ||
| Software update mode | The LED blinks with a 50 % ON / 50 % OFF duty cycle at high frequency (2 Hz blink rate). | ||
| Recovery mode | The LED remains 100 % ON (solid) after 5 seconds of holding the RECOVERY button — recovery active. |
CAN LED
Description: CAN bus status.
For all Didactum Units.
| LED | Color | Mode | Function (Percentage Indication) |
|---|---|---|---|
| CAN / CAN status | Green | Normal mode | The LED shows different states according to communication status: • Slow blinking (25 % ON / 75 % OFF) - not connected to CAN devices. • Fast blinking (50 % ON / 50 % OFF) - CAN configuration in progress. • Constant glow (100 % ON) - successfully connected to CAN devices. |
LAN port LEDs
Description: Ethernet 10/100 Base-T port status.
For all Didactum Units.
| LED | Function | Color | Description (Percentage Indication) |
|---|---|---|---|
| LED0 | Link | Yellow | Variable activity: 10–90 % ON duty cycle during network activity. |
| LED3 | 100M | Green | 0 % (OFF) - 100 Mbps connection established. 100 % ON (solid) - no connection. |
Applicable for: 100T, 500T and 550T.
| LED | Function | Color | Description (Percentage Indication) |
|---|---|---|---|
| LED0 | Link | Yellow | Variable activity: 10–90 % ON duty cycle during network activity. |
| LED3 | 100M | Green | 100 % ON (solid) - 100 Mbps connection established. 25–50 % blinking - connection attempt. 0 % (OFF) - no connection. |
RS-485 Modbus RTU LEDs
Description: RS-485 Modbus RTU status.
Applicable for: 100T, 300T, 500T and 550T.
| LED | Color | Function (Percentage Indication) |
|---|---|---|
| RS-485 status | Red | 10-50 % ON duty cycle — Data transfer active. |
| Green | 10-50 % ON duty cycle — Data receiving active. |
OSDP reader LEDs
Description: RS-485 Modbus RTU status.
Applicable for: 100T, 300T, 500T and 550T.
| LED | Color | Function (Percentage Indication) |
|---|---|---|
| RS-485 status | Red | 10–50 % ON duty cycle - data transfer active. |
| Green | 10–50 % ON duty cycle - data receiving active. |
12V Output LEDs
Description: 12V outputs status.
For all Didactum Units.
| LED | Color | Description (Percentage Indication) |
|---|---|---|
| E1, E2 / Electronic Relays Outputs: 12 V DC, 0.25 A | Yellow or Orange | 100 % ON (constant glow) - relay is ON. 0 % (OFF) - relay is OFF. |
Outlet LEDs
Description: 110/240V IEC-320 C13 outlets.
Applicable for: Didactum PDU.
| LED | Color | Description (Percentage Indication) |
|---|---|---|
| OUT 1, …, OUT 8 | Yellow or Orange | 100 % ON (constant glow) - outlet is ON. 0 % (OFF) - outlet is OFF. |
NC/NO/COM power relay terminal LEDs
Description: 110/240V IEC-320 C13 outlets.
Applicable for: 500T and 550T.
| LED | Color | Description (Percentage Indication) |
|---|---|---|
| R1, R2 (Relay 1, Relay 2) | Yellow or Orange | 100% ON (constant glow) - relay is ON. 0% (OFF) - relay is OFF. |
Didactum Monitoring System 300T
The Didactum Monitoring System 300 is a highly advanced monitoring and control unit designed specifically for mounting on DIN rails in industrial environments, server and industrial racks, as well as complex electrical systems.
Its main application lies in precise measurement of parameters such as temperature, humidity, voltage, leakages, smoke development, and airflow. Thanks to this versatile sensor integration, the system is excellently suited to ensure optimal operating conditions and prevent failures. The system features an LTE modem slot that can optionally be equipped with an LTE module to ensure a redundant internet connection—an important feature for reliable remote monitoring.