Advanced motor load monitor with MODbus RTU
The HPL500MB builds on the HPL500 by adding two programmable relay outputs and a Modbus RTU interface for remote communication. It measures true motor kW across single-phase (100-400 V) and three-phase (100-575 V) networks using a built-in 40 A current transformer and can calculate shaft power (P2) using motor efficiency modelling. Independent high and low limits with start and reaction timers drive the relays, and an isolated 0/4-20 mA analogue output provides continuous feedback.
Technical Highlights 🔧
- Supply/measuring voltage: 1x100-400 VAC or 3x100-575 VAC; frequency 45-65 Hz.
- Current range: 0.5-40 A via built-in CT; external CT options extend range; shaft power calculation optional.
- Outputs: two programmable relays (one SPDT, one SPST) rated 5 A @ 230 VAC; isolated analogue output 0/4-20 mA.
- Communication: RS-485 MODbus RTU for integration with PLC/SCADA systems.
- Timers: start delay and reaction delay for each limit; independent max and min trip set-points.
- Housing: DIN-rail mount; IP20 terminals, IP40 housing; weight 0.27 kg.
Benefits ✅
- Provides remote monitoring and control through MODbus RTU.
- Dual relays allow separate actions for overload, under-load or dP/dt alarms.
- Shank power (P2) calculation helps optimise pump and fan performance.
- Built-in CT simplifies installation while external CTs extend current range.
Applications 🚀
- Water treatment and pump stations requiring network communication and dual alarm outputs.
- Conveyors and crushers with heavy starting conditions or variable-speed drives.
- Industrial fans and blowers where accurate shaft power monitoring improves efficiency.
The HPL500MB is ideal for applications that require both advanced motor protection and communication via MODbus, providing two programmable relays and an analogue output.
FAQs
- Q: What communication protocol does the HPL500MB use?
A: It uses RS-485 MODbus RTU and can be configured for typical baud rates.
- Q: How many relays does it have?
A: Two: one SPDT and one SPST, each with independent set-points and timers.
- Q: Can it calculate shaft power?
A: Yes. An optional P2 calculation estimates shaft output power using motor efficiency models.