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  • New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB
    New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB 1
    New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB 2
    New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB 3
    New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB 4
    New item   -75.88€Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB 5

    Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB

    Code: PDM-8-MB
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  • Product description

    Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB

    The PDM-8-MB is a Sentera Controls Power over Modbus (PoM) module: from an 85–264 VAC mains supply it produces two galvanically isolated 24 VDC / 20 W channels and also works as a galvanically isolated RS485 Modbus RTU repeater. It is intended for powering and connecting Sentera controllers and sensors with Modbus communication.

    Key idea:
    This is the “heart” of the Sentera Modbus line: a single module connected to the 230 V mains – and through an RJ45 cable the devices receive both 24 VDC and data. The repeater allows the line to be extended up to 1200 m.
    Input
    85–264 VAC, 50–60 Hz
    Output
    2 × 24 VDC / 20 W (900 mA)
    Communication
    RS485 Modbus RTU repeater, up to 115.2 kbps
    Protection
    IP30

    Operating principle

    The module connects to an 85–264 VAC, 50–60 Hz mains supply and, via the RJ45 output (PoM) or terminals A, /B, GND and the 24 VDC output, to the Sentera Modbus device line. It has two galvanically isolated 24 VDC channels of 20 W (900 mA) each.

    An integrated galvanically isolated half-duplex Modbus RTU repeater regenerates the RS485 signal: automatic baud rate up to 115.2 kbps, distance up to 1200 m, and up to 32 modules can be connected (depending on distances and power requirements). The module is protected against short circuit, overload and voltage fluctuations, and a green LED indicates operation.

    Result – the whole PoM line is powered from a single mains point, and long Modbus lines are segmented and galvanically isolated. The output load depends on the input voltage (see the derating curve in the manufacturer's graph), so at low mains voltage it is worth leaving a margin in the power budget.

    Benefits PDM-8-MB?
    One module solves both the powering of Modbus devices and the extension and galvanic isolation of the communication line – fewer separate power supplies and RS485 repeaters in the panel.

    Technical specifications

    Product type Power over Modbus module with RS485 repeater
    Manufacturer / code Sentera Controls / PDM-8-MB
    Supply voltage 85–264 VAC, 50–60 Hz
    Output 2 × 24 VDC / 20 W (24 VDC / 900 mA), galvanically isolated
    Connections RJ45 output (PoM); Modbus terminals A, /B, GND; 24 VDC output
    Communication RS485, galvanically isolated, half-duplex; Modbus RTU repeater
    Baud rate Automatic, up to 115.2 kbps
    Distance up to 1200 m
    Number of modules up to 32 (depends on distances and power)
    Protections Against short circuit, overload and voltage fluctuations
    Indication Green LED – operation
    Protection class IP30
    Operating environment -20…+40 °C, 5–85 % rH non-condensing
    Weight 215 g net
    Compliance LVD 2014/35/EU, EMC 2014/30/EU, WEEE 2012/19/EU, RoHS 2011/65/EU

    Manufacturer documentation

    ✔ Recommended by Elektrotechnikos sprendimai

    Original manufacturer documentation – technical data, wiring diagrams and installation instructions.

    Main functions

    • 2 isolated 24 VDC channels – 20 W each to power Sentera PoM devices.
    • Galvanically isolated RS485 repeater – Extending the Modbus line and isolating interference.
    • Wide input range – 85–264 VAC – suitable for various mains networks.
    • Protections – against short circuit, overload and voltage fluctuations.
    • RJ45 PoM output – power and data over a single cable.
    • Up to 1200 m and 32 modules – large systems are segmented without separate repeaters.
    • Automatic baud rate – up to 115.2 kbps – nothing to set on the repeater.

    Where is it used?

    • Powering Sentera Modbus systems from the 230 VAC mains
    • Long Modbus RTU lines that need to be extended or segmented
    • Buildings with several ventilation units and many sensors
    • Systems that require galvanic RS485 isolation
    • Farm building complexes with long distances between ventilation units
    • Sentera systems with DMDBM22 / MDB-M-6 distribution boxes

    On-demand operation

    For the long Modbus line designer.
    A repeater for up to 1200 m and up to 32 modules allows a large system to be segmented.
    For farm building complex electricians.
    A single module from 85–264 VAC powers PoM devices through two isolated 20 W channels.
    For service engineers eliminating communication interference.
    Galvanically isolated RS485 eliminates interference between line segments.

    Practical application

    If a site has two groups of Sentera devices, each drawing up to 20 W, and the Modbus line to the BMS is several hundred meters long, then the PDM-8-MB powers both groups through separate isolated 24 VDC channels and extends the RS485 line up to 1200 m with its repeater.

    Application guide: how it is used in practice

    The PDM-8-MB sits at the start of the Modbus line or at a segment boundary:

    Site What is connected Result Installer's note
    Air handling unit automation 230 VAC → input; RJ45 → distribution box (MDB-M-6, DMDBM22) Sensors and controllers are powered via PoM Add up the device power – ≤20 W per channel
    Long Modbus line BMS line → Modbus terminals; continuation → RJ45 The line can be extended up to 1200 m with galvanic isolation Baud rate up to 115.2 kbps
    System with an internet gateway RJ45 → DIG-M-2 / DIGWM and sensors The system is powered and accessible via SenteraWeb Include the module current

    How to choose PoM distribution and power supply

    Requirement Recommended model
    6 RJ45 devices, surface mounting, IP65 MDB-M-6 (6 × RJ45, 1.5 A)
    Panel: 10 × RJ45 24 VDC + 12 × RJ12 3.3 VDC, -30…+85 °C DMDBM22 (DIN, 1.5 A)
    Panel: 10 × RJ45 24 VDC + 12 × RJ12 3.3 VDC (up to 0.3 A), 0…60 °C DLDBM22 (DIN, 1.5 A / 0.3 A)
    24 VDC PoM supply from 85–264 VAC mains + RS485 repeater PDM-8-MB (2 × 24 VDC / 20 W) ← this model
    Rule: add up the power of all devices powered on the line – ≤20 W (900 mA) for each 24 VDC channel; consider the manufacturer's derating curve at a lower input voltage. Use the MDB-M-6 or DMDBM22 / DLDBM22 for distribution.
    When to choose another solution: For PoM distribution – MDB-M-6 (IP65), DMDBM22 / DLDBM22 (DIN); for internet access – DIG-M-2, DIGWM.

    Pros

    • Power from 85–264 VAC
    • 2 galvanically isolated 24 VDC channels
    • Integrated galvanically isolated RS485 repeater
    • Up to 1200 m, up to 115.2 kbps
    • Short-circuit and overload protection

    Cons / limitations

    • IP30 – only in a panel / room; for PoM distribution near equipment – MDB-M-6 (IP65)
    • Operating temperature only up to +40 °C
    • Power is limited to 20 W per channel and decreases at lower input voltage
    • The mounting method is not clearly specified in the datasheet

    Safety and installation notes

    • Connection to the 85–264 VAC mains is to be made by a qualified electrician with the power disconnected.
    • Do not exceed 20 W (900 mA) on each 24 VDC channel.
    • Use in an environment of -20…+40 °C, 5–85 % rH, non-condensing.

    Quick selection guide

    85–264 VAC
    2 × 24 VDC / 20 W
    Modbus RTU
    RS485 repeater
    Galvanic isolation
    IP30
    Suitable when you need:
    • to power Sentera Modbus devices via PoM from 230 VAC;
    • to extend or segment an RS485 line with isolation;
    • to reduce the number of separate power supplies.
    Check before use:
    • the sum of the power of all devices for each channel;
    • the line length (≤1200 m);
    • the ambient temperature (up to +40 °C).
    Important reminder: The PDM-8-MB is not a controller – it only supplies power and relays Modbus RTU communication.

    FAQ

    What is the input voltage?
    The module is powered from an 85–264 VAC, 50–60 Hz mains supply.
    How much power can it supply?
    Two galvanically isolated 24 VDC channels of 20 W each (900 mA).
    Is this an RS485 repeater?
    Yes, the module has an integrated galvanically isolated half-duplex Modbus RTU repeater up to 115.2 kbps and 1200 m.
    How many modules can be connected together?
    Up to 32, depending on distances and power requirements.
    Does the baud rate need to be set?
    No, the repeater selects the transmission speed automatically up to 115.2 kbps.
    In what environment can it be used?
    The module is designed for an environment of -20…+40 °C and 5–85 % rH without condensation, protection class IP30.

    Power over Modbus module with RS485 repeater | 85-264VAC | 2×24VDC 20W | galvanic isolation | IP30 | Sentera Controls | PDM-8-MB

    Sentera PDM-8-MB – Power over Modbus module: 85–264 VAC input, 2 × 24 VDC / 20 W isolated channels, galvanically isolated RS485 Modbus RTU repeater up to 115.2 kbps and 1200 m, IP30.

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.
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