Didactum Monitoring Systems
Sensors, Elements & Network Monitoring

The System Tree is the central overview of all connected elements of your Didactum Monitoring System. Here you can add new elements, configure them, and organize them into groups.

The panel contains a categorized list of all connected elements. This area allows you to create new elements, edit configurations, view graphs for each element, and create element groups. Every element can be monitored, controlled, and set up for automatic event responses.

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System Tree Panel The System Tree of the Didactum Web Interface shows all connected elements categorized: physical sensors, virtual elements (e.g. email notifications, PING, SNMP GET) as well as system groups. New elements can be added via the + symbol in the top right of the panel.

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Create New Virtual Element Clicking the + in the System Tree opens this selection menu. Here you choose the type of virtual element you want – for example an email notification, a PING monitor or an SNMP sensor.

Every Didactum Monitoring System has built-in onboard sensors. The type and number vary depending on the device model. Onboard sensors can be used in logic schemes for automatic notifications and actions.

1. First check the comparison table of master modules to see which sensors your device has.
2. Open the Didactum Web Interface and navigate to: System Tree → Tab System Group → Tab Onboard
3. All available onboard sensors are listed there and can be configured directly.

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Onboard Sensors in the System Tree The onboard sensors are located in the System Tree under the tab “System Group” → “Onboard”. Depending on the device model (Didactum 50T, 100T, 500T or 550T), different sensors are available – e.g. temperature, voltage 1/2, Alarm LED.

Every Didactum Monitoring System has one or two built-in voltage sensors. These measure the input voltage at the main board input and can be used in logic schemes for notifications in case of voltage drop.

If Voltage 1 is greater than Voltage 2, the system uses Voltage 1 as the power input. If Voltage 1 is less than Voltage 2, the system automatically switches to Voltage 2 as the power input.

1. In the Web Interface navigate to: System Tree → Tab System Group → Tab Onboard → Voltage 1 or Voltage 2
2. A configuration window opens with the fields Name, ID, Type, Class, current state and current value.
3. Set the threshold values (Low Alarm, Low Warning, Normal, High Warning, High Alarm) to trigger notifications in logic schemes.
4. Optionally configure the hysteresis (time-based or value-based) to avoid false alarms with borderline voltages.

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Voltage Sensor Configuration Window In this window you set the name, threshold values (Low Alarm at < 6V, optimum at 12V, High Alarm at > 14V) and the hysteresis of the sensor. The current measured value is displayed in real time.

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Example 1: Monitor Single Power Source As soon as Voltage 1 falls below the set Low Warning value, an email notification is automatically triggered. This simple logic scheme is suitable for devices with a single power supply.

First create a Math Sensor with the formula (Voltage 1 – Voltage 2) and set the Low Warning threshold to -0.1. When Voltage 1 becomes smaller than Voltage 2, the Math Sensor switches to Warning state. Use this in the logic scheme:

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Example 2: Math Sensor for Voltage Difference The Math Sensor calculates the difference (Voltage 1 − Voltage 2). As soon as the result falls below −0.1, the backup power source is active. The logic scheme can then trigger email, phone call and siren simultaneously.

All connected sensors can be equipped with threshold values, hysteresis, and calibration parameters via the configuration window. The settings apply to both physical sensors and virtual elements.

1. In the Didactum Web Interface navigate to Main Menu → System Tree.
2. Click on the desired sensor in the tree structure. A modal properties window will open.
3. Make the desired settings and click OK or Apply.

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Set Threshold Values The current measured value is displayed by a small triangle on the scale. If the value is in the Normal range, the triangle appears green. The configured threshold values are evaluated by logic schemes to trigger notifications or actions.

Hysteresis prevents false alarms when measured values fluctuate near a threshold. It can be set as time-based or value-based.

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Time-based Hysteresis The system waits the set number of seconds before declaring a new state. The timer starts as soon as the measured value has left the current range. Each state can have its own time value.

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Value-based Hysteresis A state change occurs only when the measured value exceeds the current range by the set hysteresis value. Ideal for temperature sensors near thresholds – prevents alarm flapping.

Sensor values can be calibrated using the linear formula y = k × x − b. Save the calibration values to flash memory afterwards.

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Chart Tab The chart tab shows the time course of the measured values. Select the display period (seconds to days) and export the data if needed. For longer logging periods, the use of sensor dump files via the system log is recommended.

The dew point is the temperature to which air must be cooled to become saturated with water vapor. The Didactum system automatically calculates the dew point from the measured values of a connected temperature and humidity sensor.

When air is cooled below the dew point, water vapor condenses into liquid water (dew). This is particularly relevant in server rooms and data centers, as condensation on electrical components can cause short circuits. The higher the relative humidity, the higher the dew point.

1. Open the System Tree in the Didactum Web Interface and click on the + symbol.
2. In the dialog window all available virtual elements appear – select Dew Point.
3. The dew point configuration window opens.
4. Select the connected temperature sensor and humidity sensor from the dropdown lists.
5. Set the threshold values (Low Alarm, Low Warning, Normal, High Warning, High Alarm).
6. Save the configuration with OK.

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Step 1: Select Element Type In the System Tree dialog window all available virtual elements appear. Click on “Dew Point” to open the configuration window.

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Step 2: Link Sensors & Set Thresholds Select the temperature and humidity sensor. The system automatically calculates the dew point value. Set sensible threshold values – e.g. High Warning at 15 °C dew point in a server room.

All saved dew point elements are located in the Web Interface under: System Tree → Virtual Sensors. Clicking an element opens the configuration window.

The PING element checks the network reachability of a host (server, IP camera, switch, etc.). If the host fails, the element automatically switches to Alarm state – when it becomes reachable again, it returns to Normal.

Ping is a network diagnostic tool that sends ICMP echo requests and waits for replies. If no reply is received, the alarm is triggered. After the connection is restored, the sensor automatically returns to the Normal state. All Didactum Monitoring Systems support the PING element.

1. In the Web Interface open the System Tree and click on the + symbol.
2. In the dialog window select Ping. The configuration window opens.
3. Enter the target address (hostname e.g. google.com or IP address like 192.168.1.1).
4. Set the ping interval (minimum 5 seconds).
5. Enter the expected Round-Trip Time (time until expected response).
6. Confirm with OK.

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Step 1: Select PING from Element Dialog In the selection dialog “Ping” appears in the list of available virtual elements. Clicking it opens the configuration window.

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Step 2: Configure PING Enter the target address (hostname or IP), the ping interval and the round-trip time. After saving, Current Value shows the response time in milliseconds and Current State shows either Normal or Alarm.

With virtual Modbus TCP elements you can integrate external Modbus TCP devices (e.g. energy meters, UPS systems, industrial sensors) into the Didactum Monitoring System. Each measured value is displayed as a separate element in the System Tree.

Modbus TCP is a widely used industrial protocol for communication with measuring devices via Ethernet. The Didactum system supports both reading and writing Modbus TCP elements. Each register value of a Modbus device (e.g. voltage, current, power) is represented by a separate virtual element.

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Configure Modbus TCP Element For each register to be read from the Modbus TCP device, a separate virtual element is created. Enter the IP address, port (default: 502), Slave ID and register address of the device. Choose the data type according to the register content.

1. In the Web Interface open the System Tree and click on the + symbol.
2. In the dialog select Modbus TCP (Read) or Modbus TCP (Write).
3. Enter the IP address and port (default: 502) of the Modbus device.
4. Enter the Slave ID and register address.
5. Set threshold values and optionally a calculation formula.
6. Save with OK. Repeat this process for each additional measured value.

The virtual SNMP GET element allows reading data from external devices (switches, routers, servers, UPS, etc.) via SNMP PDU GET (Version 1, 2c or 3). It is available in two variants: analog (numeric value) and discrete (state comparison).

All Didactum Monitoring Systems support the SNMP GET element. The analog sensor interprets the value read via SNMP as a decimal number (e.g. temperature of a switch). The discrete sensor compares the read value with a given pattern: if it matches, the state is Normal – otherwise Alarm.

1. Open the System Tree and click on the + symbol.
2. Select SNMP Get (analog) from the dialog.
3. In the configuration window: enter name, unit, min/max value, threshold values.
4. In the Additional tab: enter SNMP server, port, version (1/2c/3), community and OID.
5. Save with OK.

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Step 1: Select SNMP GET Element In the System Tree selection dialog choose “SNMP Get (analog)” for numeric values (temperature, voltage, load) or “SNMP Get (discrete)” for text states (e.g. operating status).

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Step 2: Set Sensor Parameters (Analog) Enter name, measurement unit, min/max value (values outside = state “Not connected”) and threshold values. The optional Formula (e.g. 0.1*x+0.5) allows value transformation.

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SNMP GET (discrete) – State Comparison With the discrete sensor the read SNMP value is compared with the set Normal value (substring). If the data record contains the Normal value, the state is Normal. If not, the state changes to Alarm. The behavior can be inverted.

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Connection Tab: SNMP v1 / v2c In the “Additional” tab enter the SNMP server address, port (default: 161), protocol version (1 or 2c), community string (default: public) and the OID in numeric format.

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Connection Tab: SNMP v3 SNMP v3 offers authentication (MD5 or SHA) and optional encryption (DES or AES). Passwords must be at least 8 characters long. If you have problems with SHA, try SHA256 as a stronger alternative.