Current measuring device RoCo1065Ax / Cube 525Ax

With a single voltage base unit, you can cascade up to about 15–20 current modules in one chain. This means a single Modbus connection can gather data from up to 15–20 separate three-phase circuits (each module measuring one feeder). In practice, one Volt1000 controller can handle monitoring for up to 20 outgoing feeders. For even larger systems, two base units on separate Modbus lines could be used, effectively doubling the number of feeders covered.

Yes. The RoCo1065Ax and Cube 525Ax modules are fully interoperable on the same daisy-chain bus. You can deploy a mix of Rogowski coil modules and cube modules as needed for different feeder sizes or space constraints. The Modbus addressing and data format are uniform, so the base unit and network see a seamless multi-module system regardless of the sensor type combination.

Both module types perform the same function of measuring multi-phase AC current, but they are designed for different physical scenarios. RoCo1065Ax modules use flexible Rogowski coils that wrap around larger conductors (up to 65 mm diameter) and can handle higher currents (around 1000 A). In contrast, Cube 525Ax modules use a rigid small-form sensor (cube shape with 25 mm aperture) intended for tighter spaces or smaller cables, with a current range up to roughly 500 A. Functionally, they are identical in terms of outputs and interface – the choice mainly depends on the size of the cables and available space in the installation.

It depends on what you need to measure. The RoCo/Cube modules can operate stand-alone – each will measure currents on its connected phases and provide those readings directly over Modbus to a PLC or SCADA system. In stand-alone use, you get current magnitude values per phase (useful for load monitoring, imbalance detection, etc.). However, if you want to obtain full power and energy measurements (like calculating kW, kVA, power factor, and kWh), then a Volt1000 voltage measuring unit is required in the chain. The Volt1000 supplies the reference voltage data to the current modules so that each module can compute real-time power values for its particular feeder. In summary: for currents only, the modules alone suffice; for complete power analysis, a voltage unit is needed as the first module in the chain.

Each module has an RS-485 port and is designed to be daisy-chained using standard shielded patch cables. One end of the chain connects to your Modbus RTU master (for example, a SCADA RTU or PLC) and the current modules attach one after another. The first module in line (often the Volt1000 if present, or the first RoCo/Cube if used alone) acts as the starting point. All modules are Modbus slave devices with individual addresses. Your Modbus master polls the chain, and thanks to the built-in coordinator logic (in the Volt1000 or first module), it can retrieve measurements from any module in the cascade with a single link. This architecture means you only need one cable run back to the control system, even if you are monitoring dozens of currents. Data is transmitted in real time over Modbus, so you can see near-instantaneous values for each phase current (and voltage/power if applicable) in your software.

Absolutely. These modules were specifically designed with retrofit applications in mind. The Rogowski coil of the RoCo unit can be opened or flexed around an existing bus bar or cable, so you don’t have to cut or disconnect any live conductor. The Cube unit is very compact and can be slipped around smaller cables where space is limited. Both types attach via magnetic mounts, avoiding drilling or extensive panel modifications. In practice, installers can fit the sensors into an existing low-voltage distribution cabinet or transformer station in a short time. This makes it feasible to upgrade an old substation with modern monitoring capabilities without expensive rebuilds or extended outages.

The modules use high-resolution ADCs and true RMS measurement techniques to capture AC current waveforms. They are capable of measuring from very low currents up to their maximum range with reliable accuracy for typical power network frequencies (50 Hz or 60 Hz). The exact accuracy class isn’t explicitly stated in the brief, but they are designed for utility monitoring needs – typically on the order of 1% accuracy or better for the nominal range. Importantly, all phase currents are sampled simultaneously across modules, ensuring synchronous measurements that are suitable for power calculations and grid analysis. The system updates continuously, allowing detection of changes in loading within seconds; it also meets the requirement to deliver aggregated data (for example, 5-minute interval values) to higher-level systems as demanded by grid regulation.

Threshold or limit monitoring is managed via the Volt1000 controller unit when it’s part of the system. The base unit continuously compares the measured values (currents, voltages, phase angles, etc.) against configured setpoints. If an overload or abnormal condition is detected – for instance, a feeder current exceeding its allowable limit or a phase failure – the system can trigger an alarm output or flag the event over Modbus. The Volt1000 has configurable I/O channels (on certain models) that can be used to drive alarm relays or indicators. In a stand-alone scenario without the Volt unit, the current modules themselves do not have built-in alarm relays, but an external PLC or SCADA can easily implement threshold checks by reading the live data and issuing alerts or control commands as needed.

Yes, that is one of the key applications. Section 14a EnWG requires distribution network operators to monitor and manage controllable loads (like EV chargers, heat pumps, etc.) by obtaining near real-time feeder data. The RoCo/Cube modular current sensors, used together with the Volt1000 voltage unit, form a comprehensive power monitoring system that can be retrofitted into local substations. They provide feeder-specific voltage and current measurements within the mandated intervals (e.g. five-minute updates or faster), enabling the detection of grid stress conditions. By deploying these modules across all outgoing feeders of a transformer station, an operator gains the granular visibility needed to document grid conditions and intervene (for example, throttling loads or switching configurations) in accordance with the regulation. Essentially, the system delivers the precise, timely data backbone required for a smart grid implementation under 14a EnWG, without having to replace existing infrastructure.