Hioki ST5520 Insulation Tester

The Hioki ST5520 is an insulation resistance tester designed for fast, repeatable testing in production lines. It offers an adjustable test voltage from 25 to 1000 V DC in 1 V increments and can complete tests in as little as 50 ms.

Model Overview

• ST5520 – Insulation tester with external I/O for test control and result output.
• ST5520-01 – Insulation tester with BCD output for transferring measurement values to external systems.

Both models offer the same measurement functions and technical performance. The difference lies in their external I/O configurations.

• Test voltage: 25–1000 V DC, adjustable in 1 V increments
• Insulation resistance: up to 9990 MΩ (display range)
• Test time: from 50 ms
• Automatic discharge after testing
• Contact check and short-circuit check functions
• Comparator with adjustable upper and lower limits
• Memory for up to 10 measurement configurations
• RS-232C, analog output and external I/O

Measurement Functions and Applications

The ST5520 is designed for insulation resistance testing of electronic components and other devices requiring fast, repeatable test cycles. Its adjustable test voltage allows testing conditions to be adapted to different components and requirements.

The built-in contact check function verifies proper connection to the device under test before measurement begins. The short-circuit check function can detect micro-shorts by applying a low DC voltage before insulation testing.

After each measurement, residual voltage is automatically discharged. This helps reduce test cycle times and minimizes the need for separate discharge procedures between measurements.

Automated Testing and Communication

The instrument includes a comparator function with adjustable upper and lower limits for automatic pass/fail assessment. Up to ten measurement configurations can be stored and recalled.

The RS-232C interface enables measurement values and test results to be transferred to a PC or PLC. External I/O connections support remote control and integration into automated test systems. The ST5520-01 additionally provides BCD output for measurement data transfer.

Note: Test leads are not included as standard and must be selected separately according to the application.