DEIF TAC-311DG – Digital Tachometer/Speed Monitor for Diesel Generator Sets

The DEIF TAC-311DG is a compact, panel-mounted tachometer designed for diesel generator applications where reliable RPM indication and straightforward overspeed/underspeed protection matter. From my experience, it’s a practical fit for retrofits on older gensets and as a simple speed monitor on new panels when a full-blown controller would be overkill. You might notice that it typically accepts magnetic pickup (MPU) or W-terminal signals, which keeps wiring simple in most cases. One thing I appreciate is the clear front-face setup—quick to configure on site, especially during commissioning windows that always seem too short.

Key Features

• Purpose-built for gensets – Focused RPM display and alarm functions that slot neatly into diesel generator panels.
• Flexible speed inputs – Typically supports magnetic pickup (MPU) sensing or alternator W-terminal, suiting both new and legacy engines.
• Overspeed/underspeed protection – Programmable thresholds with relay outputs for alarm and trip; helps protect engines and drivelines.
• DIN 96 panel form factor – Standard 96×96 mm front, usually with a 92×92 mm cut-out; easy drop-in replacement in many cases.
• Simple front-panel setup – Local parameter setting without external software keeps fieldwork fast and predictable.
• Industrial temperature range – Designed to operate reliably in typical genset enclosures and plant rooms.
• Clear, stable RPM indication – Readable display suited for engine rooms where vibration and lighting vary.

Typical Use Cases

• Retrofitting older diesel gensets where you need standalone RPM display and a clean overspeed trip.
• Panel builds for standby power sets where a main controller is present, but separate speed monitoring is required by spec.
• Marine or industrial engine skids needing an independent tachometer as a secondary safety channel.

Technical Specifications

Related or Supporting Products

• DEIF AGC-150 – If you need full genset control (start/stop, protection, synchronization). TAC-311DG remains a focused speed indicator; AGC-150 is a complete controller.
• Standard Magnetic Pickup Sensor, 5/8-18 UNF (Model example: MPU-5/8-18-2W) – 2‑wire MPU for flywheel teeth; ideal speed source for the TAC-311DG when no W-terminal is present.
• Panel Gasket 96×96 (GSK-96) – Replacement sealing gasket to maintain front protection in humid or dusty rooms.
• Relay Interposing Module (RIM-24V-5A) – For isolating TAC alarm/trip relays from higher inductive loads, extending contact life.

If you’re replacing an older tachometer with non-standard scaling, let us know tooth count or PPR; we’ll pre-check that the TAC-311DG scaling fits, or suggest a variant if needed.

Installation & Maintenance

• Panel & environment: Mount in a rigid, low‑vibration panel to DIN 96 standards. Provide ventilation—avoid placing directly above heat sources. Use the front gasket to keep dust and moisture out.
• Wiring tips: Keep MPU leads twisted and away from high-current cables to reduce noise. For long runs, shielded cable with the shield grounded at one end typically works best.
• Alarms/trips: Route relay outputs via interposing relays when switching inductive loads (contactors, solenoids). Add flyback diodes on DC coils.
• Commissioning: Set pulses-per-rev and verify RPM against a handheld tach. Test overspeed/underspeed at safe simulated levels before going live.
• Routine maintenance: Annually check terminals for tightness, clean the front lens, and verify the MPU gap. Firmware isn’t typically user-updated on this unit; store parameters for records.
• Safety: Isolate power before wiring. Confirm trip logic and fail‑safe behavior with the site safety team, especially on critical engines.

Quality & Certifications

• CE marked; built under ISO 9001 quality management
• RoHS compliant materials
• Designed for industrial EMC and safety standards typically applied to panel instruments
• Manufacturer’s standard warranty applies; we provide 365-day coverage from delivery