zelsius C5-IUF
The ZENNER zelsius C5-IUF is a compact heat meter that uses ultrasonic technology to measure heating and cooling energy in buildings. With no moving parts it lasts a long time and needs no inlet or outlet straight run. Open Metering System (OMS) certification gives it direct integration with smart gateways. Connected to Argus EMS over M-Bus TCP, it lets you follow live energy consumption, instant flow and temperature difference.
| Diameter (DN) | DN15, DN20, DN25, DN32, DN40 |
| Nominal Flow (qp) | 0,6 / 1,5 / 2,5 / 3,5 / 6,0 / 10,0 m³/h |
| Measurement Principle | Ultrasonic (transit-time) |
| Max. Temperature | 105 °C or 130 °C (option-dependent) |
| Min. Temperature Difference | Δθ ≥ 3 K |
| Accuracy Class | Class 2 (EN 1434), MID MI-004 |
| Energy Output | kWh heating + kWh cooling (combined) |
| Protocol | M-Bus EN 13757-2/-3 + Wireless M-Bus / LoRaWAN |
| Connection | Via an M-Bus TCP gateway (Argus EMS compatible) |
| Certification | MID 2014/32/EU MI-004, OMS |
| Battery | ≥ 12 years |
| Protection Class | IP54 |
| Mounting | Horizontal / vertical — no inlet/outlet straight run required |
| Standards | EN 1434, MID 2014/32/EU Annex MI-004 |
Integration with Argus EMS
The zelsius C5-IUF connects to Argus EMS over M-Bus (EN 13757) two-wire meter loop, and because a ready register template ships with the platform you do not have to work out a point map on site. The field agent polls the device every 60 seconds by default, writes the reading into a local queue first and then forwards it to the server over MQTT/TLS; nothing is deleted before the server acknowledges it. Hourly and daily summaries are derived from these raw readings, and the consumption and cost screens are fed from the same series.
| Protocol | M-Bus (EN 13757) two-wire meter loop |
| Connection path | The M-Bus loop is read through an M-Bus TCP gateway |
| Default polling period | 60 seconds (field agent) |
| Points in the ready template | 14 registers |
| Consumption calculation | Difference of the heat energy index (kWh) over the period |
| Data assurance | Local queue plus server acknowledgement; nothing is deleted before it is confirmed |
When Is This Model the Right Choice?
It measures the energy carried in a heating or cooling circuit, evaluating flow together with the supply/return temperature difference. In buildings with central systems this is the measured basis of heat-cost allocation.
The M-Bus loop is two-wire and meters connect in parallel on the same pair, so no dedicated cable is pulled per meter. Loop length, conductor cross-section and the number of meters on the loop are assessed together, because an M-Bus gateway can only drive a limited load. Meter addresses (primary/secondary) are verified one by one during commissioning.