Description
MR9321 Logic Probe for AC and DC Signal Monitoring
The MR9321 Logic Probe is designed to simplify voltage state detection when working with Hioki Memory HiCorders. Built for professionals who require accurate ON and OFF signal recording, this probe delivers fast response times and reliable isolation across four input channels.
Engineered for both AC and DC applications, the MR9321 Logic Probe detects relay drive signals, control voltages, and power line states without the need for complex wiring or additional signal conditioning. Its ability to detect voltage interruptions makes it especially valuable for troubleshooting unstable power lines, relay timing issues, and control circuit failures.
Each of the four channels is electrically isolated from the main unit, improving measurement safety and reducing the risk of signal interference. The probe supports high and low detection ranges, allowing users to monitor voltages from low-level DC signals up to high-voltage AC lines. This flexibility makes it suitable for industrial equipment, automation systems, and power distribution diagnostics.
With a high-speed response time of just 1 ms on rising edges, the MR9321 Logic Probe captures fast voltage transitions accurately, ensuring no critical events are missed during recording. Its compact housing and lightweight design make it easy to deploy in tight panels or crowded test environments.
The MR9321 connects directly to compatible Memory HiCorders using a miniature terminal interface. Before installation, users should verify terminal compatibility to ensure proper connection. Once installed, the probe integrates seamlessly into existing measurement setups, allowing clear high and low state recording without altering the signal path.
Whether you are monitoring relay operations, diagnosing power interruptions, or validating control logic behavior, the MR9321 Logic Probe provides dependable performance, fast detection, and safe operation in a compact form factor.
Technical Specifications Table
| Specification | MR9321 Logic Probe |
| Function | AC and DC voltage state detection |
| Channels | 4 isolated input channels |
| Detection Type | HIGH and LOW state recording |
| Input Resistance | 100 kΩ or higher (HIGH), 30 kΩ or higher (LOW) |
| High Detection Range | 170 to 250 V AC, ±DC 70 to 250 V |
| Low Detection Range | 60 to 150 V AC, ±DC 20 to 150 V |
| Low Output Detection | 0 to 30 V AC or ±DC 0 to 43 V |
| Response Time | 1 ms rise, 3 ms fall |
| Max Allowable Input | 250 Vrms (HIGH), 150 Vrms (LOW) |
| Connection Type | Miniature terminal |
| Cable Length | Main unit 1.5 m, input section 1 m |
| Dimensions | 62 mm × 128 mm × 20 mm |
| Weight | 300 g |
| Included Accessories | Carrying case, instruction manual |
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