Line Frequency Monitor · LFM Series

Line Frequency Monitor

45.00-55.00 Hz Mains Frequency 2 decimal place

High-Accuracy Measurement Microcontroller-based design delivers accuracy better than 0.02% — up to 3 decimal places on made-to-order versions.

Wide Display Range Available in ½-inch DIN to 12-inch jumbo LED, with 4-digit or 5-digit configurations for any viewing distance.

Auto Input from Mains Signal derived directly from the power supply line — no additional input transducer required.

Industrial-Grade Construction MS powder-coated enclosure, IP54/IP65 rated, wall-mount or roof-hanging installation.

Product Models

Line Frequency Monitor Models

2" / 4"

4 Digit Frequency Indicator

Models LFM02-4D, LFM04-4D

Input Direct Mains Supply

Range 40.00 to 60.00 Hz

Resolution 0.01 Hz

Accuracy 0.02%

Display type FnD 7 Segment

Display height 2" / 4"

Enclosure MS Powder Coated

Dimensions

2" 280 × 145 × 135 mm

4" 460 × 180 × 80 mm

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2" & 4" 5 Digit 5 Digit Indicator

5 Digit Indicator

Models LFM02-5D, LFM04-5D

Input Direct Mains Supply

Range 40.000 to 60.000 Hz

Resolution 0.001 Hz

Accuracy 0.002%

Display type FnD 7 Segment

Display height 2" / 4"

Enclosure MS Powder Coated

Dimensions

2" 280 × 145 × 135 mm

4" 460 × 180 × 80 mm

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Need a different size, input range, or enclosure? Tell us your requirement — we custom-build to spec.

About This Product

Precision Line Frequency Monitoring for Power Plants and Industrial Grids

The Line Frequency Monitor is a precise and reliable microcontroller-based instrument designed for accurate measurement of power line frequency to an accuracy of more than 0.02%, it ensures grid stability and optimizes power generation and synchronization in power generation and load dispatching centers, process industries, and other critical environments. Equipped with advanced accuracy capabilities of up to 2 decimal places (or up to 3 decimal places for the made-to-order version), this essential tool provides precise frequency monitoring for efficient operations.The 7-segment LED display, available in sizes from 4 to 12 inches, offers easy readability of real-time frequency measurements. Its robust design, wide operating voltage range, and suitability for power plants, manufacturing facilities, and research laboratories make it the ideal solution for accurate line frequency monitoring.

Measures line frequency accurately up to 2/3 decimal places
No calibration required.
Easy plug and play operation
Large display visible from distance

40–60 Hz

MEASUREMENT RANGE

½", 1", 2", 4", 6", 8", 12"

DISPLAY SIZES

0.01 Hz

RESOLUTION

RS485 Modbus

OUTPUT OPTIONS

Technical Specifications

Full Specification Table

Parameter	Specification
	LFM4X	LFM5X
Digits	4	5
Range	40.00-60.00 Hz	40.000-60.000 Hz
Resolution	0.01 Hz	0.001 Hz
Input Signal	Auto from Power Supply / 4-20 mA (On Order)	Auto from Power Supply / 4-20 mA (On Order)
Display Height	½ Inch, 1 Inch, 2 Inch, 4 Inch, 6 Inch, 8 Inch, 12 Inch Refer Display Size Table	½ Inch, 1 Inch, 2 Inch, 4 Inch, 6 Inch, 8 Inch, 12 Inch Refer Display Size Table
Type	DIN Mounted / Jumbo	DIN Mounted / Jumbo
Display Color	Red	Red
Power Supply	230 V AC +/- 10% / 110V AC +/- 10% (On Order)	230 V AC +/- 10% / 110V AC +/- 10% (On Order)
Mounting	Wall Mounting / Roof Hanging	Wall Mounting / Roof Hanging
IP Rating	IP54	IP54
Enclosure	MS Powder Coated	MS Powder Coated

Model	Variant	Dimensions (W × H × D mm)	Typical Viewing Distance
LFM02	Line Frequency Monitor, 2 Inch	280 × 145 × 135	20 m
LFM04	Line Frequency Monitor, 4 Inch	460 × 180 × 80	50 m
LFM06	Line Frequency Monitor, 6 Inch	750 × 260 × 80	75 m
LFM08	Line Frequency Monitor, 8 Inch	800 × 280 × 80	100 m
LFM12	Line Frequency Monitor, 12 Inch	1120 × 400 × 80	125 m
LFM04-5D	Line Frequency Monitor, 4 Inch, 5 Digit	550 × 180 × 80	50 m
LFM06-5D	Line Frequency Monitor, 6 Inch, 5 Digit	550 × 260 × 80	75 m
LFM08-5D	Line Frequency Monitor, 8 Inch, 5 Digit	1000 × 280 × 80	100 m
LFM12-5D	Line Frequency Monitor, 12 Inch, 5 Digit	1370 × 400 × 80	125 m

Full dimensional drawings and wiring diagrams are in the datasheet. Download Datasheet (PDF)

How to Order

Ordering Information

Parameter	Options
Code Format	`LFM[SIZE]-[CABINET]-[DIGITS]-[OUTPUT]-[IPRATING]-[PS]`
Display Size	02 — LFM02 (2" Display) 04 — LFM04 (4" Display) (default) 06 — LFM06 (6" Display) 08 — LFM08 (8" Display)
Cabinet	SS — Single Side (default) DS — Both Side
Digits	4D — 4 Digits (0–9,999) (default) 5D — 5 Digits (0–99,999)
Output	OP0 — No Output (default) OP4 — RS485 Modbus RTU
IP Rating	IP54 — IP54 Rain + Dust Resistant (default) IP65 — IP65 Fully Dust Tight, Air Tight
Power Supply	PS1 — 230V AC, 50Hz (default) PS4 — 110V AC, 50Hz