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Details voltage, current, power, frequency, and display specifications.
Specifies accuracy classes for voltage, current, power factor, and energy.
Lists operating temperature, storage, transportation, and reference temperature ranges.
Describes pulse outputs, RS485 Modbus RTU parameters, and communication settings.
Provides DIN rail dimensions, mounting type, ingress protection, and material.
Explains meter initialization, self-checking, and how to scroll through displayed measurements.
Details how to enter set-up mode and configure CT1 primary current.
Illustrates the wiring connections and provides overall meter dimensions.
Provides visual guidance for installing the meter on a DIN rail.
Details voltage, current, power, frequency, and display specifications.
Specifies accuracy classes for voltage, current, power factor, and energy.
Lists operating temperature, storage, transportation, and reference temperature ranges.
Describes pulse outputs, RS485 Modbus RTU parameters, and communication settings.
Provides DIN rail dimensions, mounting type, ingress protection, and material.
Explains meter initialization, self-checking, and how to scroll through displayed measurements.
Details how to enter set-up mode and configure CT1 primary current.
Illustrates the wiring connections and provides overall meter dimensions.
Provides visual guidance for installing the meter on a DIN rail.
The Eastron SDM120-CTM is a single-phase multifunction DIN rail meter designed for a wide range of applications, including residential, utility, and industrial settings. This compact and economical device is engineered to measure and display various important electrical parameters, making it a versatile tool for energy monitoring. Its design prioritizes ease of installation and clear data presentation, ensuring that users can effectively manage and track their energy consumption.
The primary function of the SDM120-CTM is to accurately measure and display key electrical parameters in single-phase systems. It is capable of measuring active energy (kWh), reactive energy (kVArh), active power (kW), reactive power (kVAr), apparent power (kVA), power factor (PF), frequency (Hz), demand (dmd), voltage (V), and current (A). This comprehensive measurement capability allows for a detailed understanding of the electrical characteristics of a system.
A significant feature of the SDM120-CTM is its bi-directional energy measurement, which includes both import and export active energy (kWh) and reactive energy (kVArh). This makes it particularly well-suited for applications involving solar PV energy metering, where tracking both energy consumed from the grid and energy fed back into it is crucial. The meter can differentiate between energy flowing in and out, providing a complete picture of energy transactions.
For remote monitoring and data acquisition, the SDM120-CTM is equipped with an RS485 communication port. This port supports the Modbus RTU protocol, allowing the meter to be integrated into larger building management systems or energy monitoring networks. Through Modbus commands, users can remotely read measured values and configure certain communication parameters, enhancing the meter's utility in smart grid and industrial automation contexts.
The device also provides two pulse outputs, which are a common method for integrating energy meters with external data loggers or control systems. One pulse output is configurable, allowing users to set it to represent total, import, or export kWh or kVArh, with a configurable pulse constant. The other pulse output is fixed to represent total kWh, providing a consistent signal for energy accumulation. These pulse outputs offer a simple yet effective way to transmit energy consumption data to other devices.
The SDM120-CTM is designed for user-friendly operation and clear data presentation. It features a white backlit LCD screen, which ensures excellent readability of the displayed parameters, even in low-light conditions. The LCD screen is capable of displaying a wide range of values, with a maximum reading of 999,999 kWh, accommodating significant energy consumption data.
Navigation and configuration of the meter are straightforward, primarily managed through a single button on the front panel. Upon power-on, the meter undergoes an initialization and self-checking program, displaying a full screen for a few seconds, followed by the software version. After this, the default display shows the total active energy (kWh). Users can scroll through various measured values by simply pressing the button. This intuitive interface allows for quick access to essential information without complex menus.
For more advanced settings, the meter offers a setup mode. By pressing and holding the button for three seconds, users can enter this mode, indicated by "-SET-" on the LCD. Within the setup mode, certain parameters can be configured directly from the front panel. For instance, the CT (Current Transformer) ratio can be set. The meter supports a range of primary current values for CT connection, and the secondary current can be set to 1A or 5A. The configuration process involves navigating through options and confirming selections by holding the button, making it accessible for on-site adjustments.
The meter's DIN rail mounting (35mm) simplifies installation in electrical panels and enclosures. Its compact dimensions (18x118x64 mm WxHxD) ensure it occupies minimal space, making it suitable for installations where panel space is at a premium. The self-extinguishing UL94V-0 material of the casing contributes to safety, while its IP51 ingress protection rating indicates suitability for indoor environments, protecting against dust and dripping water.
The SDM120-CTM is designed for low maintenance, focusing on reliability and durability. Its robust construction and adherence to international standards for accuracy (Class 1 for active energy, Class 2 for reactive energy) ensure consistent performance over time. The meter's operational temperature range of -25°C to +55°C and storage temperature range of -40°C to +70°C indicate its resilience in various environmental conditions, reducing the likelihood of performance degradation due to temperature fluctuations.
The device's internal self-checking program, performed upon power-on, serves as a basic diagnostic feature, ensuring that the meter initializes correctly. While the manual does not detail extensive user-level maintenance procedures, the design implies a "set it and forget it" approach, typical of modern energy meters. The use of a white backlit LCD, while enhancing readability, also contributes to the meter's long-term usability by providing clear data presentation without requiring external lighting.
The RS485 Modbus RTU communication interface not only facilitates remote reading but also allows for remote configuration of certain parameters. This capability can reduce the need for physical access to the meter for adjustments, thereby minimizing maintenance effort and costs, especially in large-scale deployments. Parameters such as baud rate, parity, and Modbus address can be configured via Modbus commands, offering flexibility in network integration without manual intervention.
The meter's design, with its focus on standard interfaces (DIN rail, RS485) and robust electrical specifications (e.g., AC voltage withstand, impulse voltage withstand, overcurrent withstand), ensures compatibility and longevity within typical electrical installations. The absence of moving parts, characteristic of electronic energy meters, inherently reduces wear and tear, contributing to a longer operational life and lower maintenance requirements compared to older, electromechanical meters. The configurable pulse outputs also offer a reliable and simple way to interface with other systems for data logging, further simplifying the overall system maintenance by providing a standardized output.
General| Rated Voltage (Un) | 230V AC |
|---|---|
| Base Current (Ib) | 5A |
| Maximum Current (Imax) | 100A |
| Accuracy | Class 1 |
| Communication | RS485 |
| Display | LCD |
| Impulse Voltage | 4kV |
| Operating Temperature | -25°C to +55°C |
| Storage Temperature | -40°C to +70°C |
| Mounting | DIN rail |
| Width | 1 module (17.5 mm) |
| Backlight | No |
| MID Certified | Yes |
| Type | Single-phase energy meter |
| Current Range | 0.0 - 100A |
| Starting Current (Ist) | 0.004A |
| Frequency | 50Hz |
| Protocol | MODBUS |
| Power Consumption | < 2W |
