Didactum Knowledge Base · Didactum Devices
Didactum PDU 4M
An overview of the device, its connections, and technical specifications of the Didactum PDU 4M – the remotely switchable, per-outlet metering Power Distribution Unit for server rooms, data centers, and industrial infrastructures.
What makes the PDU 4M stand out
A remotely switchable, per-outlet metering Power Distribution Unit for intelligent power distribution in the rack.
4× C13 outlets
Each outlet individually switchable (on/off/reset/toggle) and individually metered, 10A / 110–240V.
Precise power metering
Voltage, current, power, frequency, active/apparent power, and active/real energy per outlet, accuracy <1%.
CAN environmental monitoring
One CAN port for up to 24 daisy-chained CAN sensors and expansion units.
Flexible alerting
Email, FTP log, syslog, SNMP trap, web-to-SMS, PUSH, and Telegram notifications.
Web-based, SNMP & app
Control via web interface, mobile app, or M2M protocols such as REST API and SNMP.
Logic schemes & timers
Up to 300 elements – sensors, triggers, timers, and logic schemes for automated workflows.
USB camera & data logging
Optional USB camera for JPEG alarm images, SDHC/SDXC memory card (up to 512GB) for up to 5 years of data storage.
Made in EU
Developed and manufactured in the EU, with German support included.
Typical use cases
- Power distribution within 19" rack cabinets in data centers
- Monitoring the power consumption of servers and network devices
- Remote restart of unresponsive systems
- Remote management of base stations, network switches, and repeaters
- Automated system restarts on failure (telecommunications)
- Scheduled on/off switching of individual outlets via scheduler
- Environmental monitoring of temperature, humidity, smoke, or water leakage via CAN sensor
- Energy efficiency optimization through per-outlet peak load analysis
Connections & controls
All ports, buttons, and LEDs on the front and rear of the PDU 4M at a glance.
Rear view – connections 1–5
Rear view: DC 12V backup, chassis ground, fuse, C14 power inlet, and the four C13 outlets.
DC 12V POWER
Keeps the board running and enables alarm notifications to be sent if the main C14 inlet loses power.
Chassis ground
Chassis grounding, M4 thread – improves immunity to conducted and radiated RF interference. Connection by a qualified electrician is recommended.
Inlet fuse
10A, 5×20mm.
Power inlet
C14 inlet, 110–240V AC, 50/60Hz, protected by a 10A/5×20mm fuse.
Outlets 1–4
4× C13 outlets, 110–240V AC, 50/60Hz – each individually switchable (on/off/reset/toggle) and individually meterable.
Front view – connections 6–13
Front view: temperature sensor, reset/restart button, status LEDs, CAN, LAN, SD card, DIP switch, and USB.
Temperature sensor
Built-in sensor, accuracy ±1°C.
Factory reset and restart button
Factory reset: hold the button for more than 5 seconds – the ERR LED blinks, and after 20–60 seconds the device is reset and reachable again via the ACT LED. Restart: hold the button for 2 seconds to restart the device.
Status LEDs R1–R4, ALARM, ERR, ACT
R1–R4 show the switching state of the four outlets (orange = relay on). ALARM is freely programmable. ERR (red) indicates errors/update mode, ACT (green) the system status.
CAN port
Digital RJ12 6P4C connector for CAN sensors, expansion units, and devices, daisy-chainable. Status LED CAN (green): slow blinking = nothing connected, fast blinking = configuration in progress, solid = devices connected.
LAN port
Ethernet 10/100 Base-T with integrated Ethernet switch. Orange LED indicates network traffic, green LED the connection status (blinks during startup/connection setup, solid when a connection is established).
SD card
MicroSD card slot with ejector – for data storage (SDHC/SDXC up to 512GB) or system recovery.
DIP switch N/R
"N" normal operation (default position, always left). "R" loads a clean system image from the SD card for full system recovery.
USB
Micro-USB 2.0 port – for USB camera recording, USB flash for system logs, and system recovery.
Connection diagram – full overview
Full overview of all connections on the front and rear in a single diagram.
What's included in the box
Please check the scope of delivery for completeness upon receipt and report any missing or damaged parts to your supplier immediately.
- Didactum PDU 4M (monitoring/switching device)1 pc.
- EU Schuko cable (C13, 0.75 mm², 230V, 10A)1 pc.
- RJ45 patch cable, LAN/Ethernet, 3 m1 pc.
- Micro-USB-C OTG adapter cable1 pc.
- Terminal block, 3-pin, 3.81 mm1 pc.
- Self-adhesive rubber feet4 pcs.
- Quick start guide1 pc.
For rack mounting, optional 19" brackets, mounting brackets for two PDUs, vertical rack brackets, and wall mounts are available separately in the shop.
Dimensions in detail
Technical specifications
Device management
| Device management | Web interface, mobile app, SNMP, REST API |
|---|---|
| Device type | Switched & metered-by-outlet PDU |
Interface
| LAN | Ethernet 10/100 Base-T, 100 Mbit/s, integrated Ethernet switch |
|---|---|
| Processor | Dual-core ARM Cortex-A7, 720 MHz |
| Memory (RAM) | 128 MB |
| Clock | Built-in real-time clock |
| Timer | Built-in watchdog |
Outlets & power metering
| Outlets | 4× IEC 320 C13, 10A, 110–240V AC, individually switchable (on/off/reset/toggle) |
|---|---|
| Switching behavior | Zero-cross switching to protect connected equipment |
| Measurement accuracy | Better than 1% |
| Parameters measured per outlet | Voltage (V), current (A), power (W), frequency (Hz), active power (W), apparent/real power (W), active energy (kWh), real energy (kWh) |
| Power-up state | Switching state after power restoration is configurable (on/off) |
| Scheduler | Time-controlled switching per outlet via timer/schedule |
Sensors & logic
| CAN port | 1× RJ12 6P4C, up to 24 daisy-chained CAN devices/sensors |
|---|---|
| Max. number of elements | 300 (sensors, notifications, triggers, timers, logic schemes, etc.) |
| Built-in sensor | Temperature sensor, ±1°C |
| Analog sensors | Via optional VT408 expansion unit (8 additional ports each) |
| Virtual elements | PING, timer, trigger, logic schemes, SNMP GET, virtual computation elements |
Network / protocol support
| Network protocols | DHCP, HTTP, HTTPS, DynDNS, SSL/TLS, SMTP, FTP, syslog, RADIUS |
|---|---|
| SNMP | v1, v2c, v3 |
| Modbus | Modbus TCP/IP |
| VPN | OpenVPN (client/server) |
| Notifications | Email, FTP log, syslog, SNMP trap, web-to-SMS, PUSH, Telegram |
Power supply
| Power inlet | 1× C14 inlet, 110–240V AC, 50/60Hz |
|---|---|
| Fuse | 10A, 5×20mm |
| DC 12V backup | Keeps the board active during a main power failure and continues to enable alarm notifications |
I/O & video
| USB | 1× Micro-USB 2.0 (camera, flash drive, system recovery) |
|---|---|
| USB cameras | 1 |
| IP cameras | up to 4 |
| SD card | MicroSD (SDHC/SDXC up to 512GB), data storage up to 5 years |
Environmental conditions
| Operating temperature | -10 to +80°C |
|---|
Mechanics & housing
| Mounting | Desktop or 19" (with optional rackmount kit) |
|---|---|
| Origin | Made in EU |
Frequently asked questions
What is the Didactum PDU 4M and what is it used for?
The Didactum PDU 4M is a remotely managed, switched, and per-outlet metering Power Distribution Unit with four IEC 320 C13 outlets (110/240V). Each outlet can be controlled independently (on/off/reset/toggle) and is individually metered with high accuracy. It is suitable for demand-based power distribution and energy monitoring in server rooms, data centers, and industrial environments.
How are the four outlets switched and metered individually?
Via the web interface, a mobile app, or M2M protocols such as REST API and SNMP, each of the four outlets can be switched on, off, toggled, or reset independently. At the same time, the device measures voltage, current, power, frequency, active/apparent power, and active/real energy per outlet with an accuracy better than 1%. Zero-cross switching also protects connected equipment during switching operations.
Which sensors can be connected via the CAN port?
Up to 24 digital CAN sensors and expansion units can be connected in a chain via the CAN port – for example, for temperature, humidity, smoke, motion, or water leakage. Analog sensors can also be integrated via the optional expansion unit.
How does the PDU 4M differ from the PDU 4T and PDU 8T?
The PDU 4M measures and switches each of its four outlets individually (metered-by-outlet). The PDU 4T also offers four switchable C13 outlets, but without detailed per-outlet metering. The PDU 8T extends the PDU 4T concept to eight switchable outlets. The choice depends on whether pure remote switching is sufficient or whether precise per-outlet energy metering is also required.
How are alerts triggered for critical events?
Notifications are sent via email, FTP log, syslog, SNMP trap, web-to-SMS, PUSH, or Telegram. Logic schemes also allow automated responses, such as restarting a server in response to a failed PING or automatically switching off an outlet in the event of overheating.
Can the PDU 4M be integrated into existing network management systems?
Yes. The device supports SNMP v1/v2c/v3, Modbus TCP/IP, and a REST API, allowing it to be integrated into common monitoring and DCIM solutions such as Nagios, CheckMK, or Zabbix.
How is the PDU 4M mounted?
The PDU 4M can be freely placed as a desktop device or mounted in a 19" rack using optional accessories. Available separately are 19" 1U brackets, a bracket for two PDUs, vertical rack brackets, and a wall mount.
Questions about the PDU 4M?
Our support team in Germany offers free advice on selection, connection, and setup.
Scope of delivery
- 1 x Monitoring device Didactum PDU 4M
- 1 x EU Schuko C13 0. 75 мм2 230V 10A cable
- 1 x RJ45 cable 3m
- 1 x Micro USB-C OTG adapter cable
- 1 x connector plug 3-pin, 3.81 mm
- 4 x self-adhesive rubber feet
- 1 x quick start guide
Manufacturer information:
Didactum® Security GmbH
Im Mühlenfeld 4
48163 Münster
Germany
Phone: (+49) 2501 92 90 160
Email: info@didactum-security.de
Suitable CAN expansion units
Suitable CAN sensors
Suitable sensors if you are using an extension unit:
