IMPLEMENTASI MODBUS I/O DAN WEB-HMI PADA SIMULATOR OLTC SISTEM OTOMASI GARDU INDUK

Pengujian panel kontrol dan proteksi pada sistem otomasi gardu induk memerlukan media simulasi yang mampu merepresentasikan fungsi operasi peralatan secara aman dan efisien sebelum proses commissioning. Penelitian ini bertujuan mengimplementasikan Modbus I/O dan Web-HMI pada simulator On Load Tap Changer (OLTC) sebagai media pengujian, validasi fungsi kontrol, monitoring, dan komunikasi data pada panel Remote Control Panel (RCP). Sistem dibangun menggunakan Modbus Remote I/O sebagai media akuisisi data, Node-RED sebagai pengolah logika kontrol, dan FUXA sebagai platform Web-HMI. Simulator mampu merepresentasikan operasi Raise dan Lower, posisi tap, keluaran Binary Code Digital (BCD) 5-bit, serta sinyal analog 4–20 mA. Hasil pengujian menunjukkan bahwa fungsi Raise dan Lower bekerja sesuai logika dengan rentang operasi tap 0–17. Pengujian keluaran BCD 5-bit menunjukkan seluruh 18 posisi tap (0–17) menghasilkan kombinasi bit berbobot 1–2–4–8–10 yang sesuai dengan tabel mapping sehingga diperoleh akurasi 100% tanpa kesalahan kombinasi bit. Sementara itu, pengujian keluaran analog 4–20 mA menggunakan Fluke 705 Process Calibrator menunjukkan deviasi keluaran hanya sebesar +0,008 hingga +0,009 mA, dengan rata-rata error 0,0085 mA (0,053% span) dan error maksimum 0,009 mA (0,056% span), sehingga keluaran Analog Output memenuhi kebutuhan simulasi sistem OLTC. Hasil tersebut menunjukkan bahwa integrasi Modbus Remote I/O, Node-RED, dan FUXA mampu menghasilkan sistem monitoring dan pengendalian yang akurat, stabil, dan layak digunakan sebagai media pengujian, validasi fungsi, serta pendukung proses Quality Control pada sistem otomasi gardu induk.

Testing control and protection panels for substation automation systems requires a simulation tool capable of safely and efficiently representing equipment operations prior to commissioning. This study aims to implement Modbus I/O and a Web-HMI within an On-Load Tap Changer (OLTC) simulator to serve as a medium for testing and validating control functions, monitoring capabilities, and data communication for Remote Control Panels (RCP). The system utilizes Modbus Remote I/O for data acquisition, Node-RED for control logic processing, and FUXA as the Web-HMI platform. The simulator is capable of representing "Raise" and "Lower" operations, tap positions, 5-bit Binary Coded Decimal (BCD) outputs, and 4–20 mA analog signals. Test results demonstrate that the "Raise" and "Lower" functions operate according to the logic across a tap range of 0–17. Testing of the 5-bit BCD output confirms that all 18 tap positions (0–17) generate bit combinations based on the 1–2–4–8–10 weighting scheme that align with the mapping table, achieving 100% accuracy with no bit combination errors. Meanwhile, testing of the 4–20 mA analog output using a Fluke 705 Process Calibrator reveals an output deviation of only +0.008 to +0.009 mA, with an average error of 0.0085 mA (0.053% of span) and a maximum error of 0.009 mA (0.056% of span), thereby meeting the requirements for OLTC system simulation. These results indicate that the integration of Modbus Remote I/O, Node-RED, and FUXA yields an accurate and stable monitoring and control system suitable for testing, functional validation, and quality control support within substation automation systems.