DEIF VTR-5-NB – True RMS voltage transducer for 0–500 VAC to 4–20 mA monitoring

The DEIF VTR-5-NB is a compact, DIN‑rail voltage transducer designed to convert an AC line voltage (typically up to 500 VAC) into a clean, isolated 4–20 mA signal for PLCs, SCADA, and protection relays. From my experience, it’s a straightforward way to get reliable RMS voltage feedback out of switchboards, motor control centers, and generator panels without stuffing the PLC with extra analog front ends. You might notice that the NB variant is favored when engineers want a simple 4–20 mA loop for stable long‑run wiring in industrial cabinets.

Company’s Order Placement Process and Guarantees

• Warranty period: 365 days
• Delivery time: 1 week for in‑stock items, no more than one month at the latest
• Payment: 50% advance payment, full payment prior to delivery
• Express delivery: FedEx, UPS, DHL

Key Features

• True RMS measurement – Captures accurate voltage under distorted waveforms, which is common with VFDs and generator sets.
• 0–500 VAC input range – Suited for low‑voltage three‑phase systems (line‑to‑line) and single‑phase feeders, 50/60 Hz.
• 4–20 mA isolated output – Stable, noise‑resistant signal for PLC/SCADA analog inputs, typically scaled to match your nominal line voltage.
• DIN‑rail mounting – Quick to install inside standard control panels with minimal footprint.
• Galvanic isolation – Helps protect downstream IO cards and reduces ground loop issues in mixed‑voltage cabinets.
• Industrial temperature range – Built for continuous operation in electrical rooms and MCCs where ambient conditions vary.
• Low maintenance – No moving parts; routine checks typically involve verification of scaling and terminal tightness.

Technical Specifications

Note: Scaling and auxiliary supply variants exist across the VTR series; the figures above reflect common VTR‑5‑NB configurations used in low‑voltage panels.

Related or Supporting Products

• DEIF VTR-3-NB – Same concept with a 300 VAC input range when 500 VAC headroom isn’t needed.
• DEIF VTR-5-NP – 0–10 VDC output variant used where the PLC prefers voltage rather than current input.
• DEIF CTR-5-NB – Matching current transducer (5 A/1 A CT secondary to 4–20 mA) for complete V and I monitoring on the same panel.
• Standard 500 V rated voltage dividers and fuses – For safe tapping of phases; typically gG fuses and compact terminal blocks rated for 500 V AC.

Installation & Maintenance

• Cabinet environment: Install on TS‑35 rail in a closed panel with basic ventilation. Maintain clearance for wiring and heat dissipation.
• Wiring practice: Use shielded twisted pair for the 4–20 mA loop in noisy environments; terminate shields at one end to avoid ground loops.
• Protection: Include suitably rated fuses and a disconnect on the voltage input. Verify that measured circuits do not exceed the specified range.
• Grounding: Follow the panel’s protective earth scheme; keep high‑voltage conductors separated from low‑level analog wiring.
• Commissioning: Calibrate scaling in the PLC/SCADA to your nominal line voltage (e.g., map 4 mA to 0 VAC and 20 mA to 500 VAC).
• Routine checks: Annually verify terminal torque, inspect for discoloration, and spot‑check output against a portable reference meter.
• Firmware/updates: Analog transducers like this typically have no firmware; maintenance focuses on wiring integrity and periodic functional tests.
• Safety: Only qualified personnel should connect to live circuits. De‑energize and lockout where possible before servicing.

Quality & Certifications

• CE compliant for industrial environments
• RoHS compliant materials
• Manufactured under ISO 9001 quality management
• Supplier warranty: 365 days from delivery

A quick field note from a recent panel build: we paired the VTR‑5‑NB with a PLC analog input card over a 30‑meter run in a motor hall; the 4–20 mA loop stayed rock‑steady even with several VFDs nearby. That’s typically where this unit earns its keep.