[New Product Launch] Acrel APM521 Electricity Meter, UL Certified + Multiple Installation Options, More Compliant for Overseas Export

Dec 26, 2025

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Overview

The APM521 network power meter (hereinafter referred to as the meter) is designed according to IEC international standards and features full power measurement, power statistics, power quality analysis, event recording, and network communication functions. It is primarily used for comprehensive monitoring of power grid quality. This series of meters is equipped with feature-rich DI/DO and AO modules, enabling flexible full power measurement of electrical circuits and monitoring of switch status.

UL certification empowers expansion into international markets.

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Product Function

Measured parameters	Total electrical measurement
Measured parameters	Four-quadrant energy, Four - quadrant reactive electric energy, Split phase electricity, Apparent energy, Multi-rate energy
Pulse output	Total active power, total reactive powerelectrical energy pulse output
Demand	Three-phase current, active power, reactive power, apparent power real-time demand andmaximum demand (including timestamp), last month's maximum demand (including timestamp)
Extreme value statistics	Current, line voltage, phase voltage, active power, reactive power and other electrical parameters extreme values of this month and last month (including time stamps)
Power quality	Unbalance of current,line voltage, phase voltage
	Voltage phase angle, current phase angle
	Total (odd,even) harmonic content of voltage and current
	Harmonic content of voltage and current(2-63 times)
	Voltage peak coefficient
	Telephone waveform factor
	Current K-factor
	Vector
	Voltage and current waveform
	Fundamental voltage, current and power factor
	Voltage deviation, frequency deviation
	Positive-sequence voltage, negative-sequence voltage, zero-sequence voltage
	Positive-sequence current, negative-sequence current, zero-sequence current
Frozen electric energy	24 -hour frozen electric energy, 31 -day frozen electric energy, December frozen electric energy, regular-time frozen electric energy
Event logging	DlDO records,which can record the last 128 DID records
Alarm logging	The last 128 alarm records can be recorded
Communication	Modbus- RTU protocol, DL/T 645-2007 statute
Optional features	4-channel digital input and 2-channel digital output
	2 channels of analog output, 4-20mA
	Expand the second RS485 communication channel with Modbus- RTU protocol
	Expand Ethernet communication with the MODBUS-TCP protocol, FTP protocol

Technical Parameters

Item			Performance Parameters
	Voltage	(UL、CE) Rated voltage (UL、CE)	66VACL-N 115VACL-L 230VACL-N 400VACL-L 277VACL-N 480VACL-L 400VACL-N 690VACL-L
		(CPA) Rated voltage (CPA)	3P3L	3P4L
			3x100V 3x380V 3x690V	3x57.7/100V 3x220/380V 3x400/690V
		Overload	1.2 times rating(continuous) 2times therating for 1 second
		Power consumption	<IVA
		Accuracy class	Error ±0.2%
	Cunrent	(UL、CE) Rated cunrent (UL、CE)	1A、5A
		(CPA) Rated current (CPA)	0.015-0.075 (6) A (Active energy) 3Xl (6) A (Reactive energy)
		Overload	1.2times rating(continuous) 10 times the rating for 1 second
		Power consumption	<0.2VA
		Accuracy class	Error ±0.2%
	Power		Active, reactive, apparent power, error ±0.2%
	Grid frequency		UL、CE	50Hz/60Hz, error ±0.2%
			CPA	50Hz, error±0.2%
	Response rate		≤200ms (voltage, current, power)
			≤1s(electrical energy)
	Measurement category		66ULN(+20%) 115ULL(+20%) CATIII 230ULN(+20%) 400ULL(+20%) CATIII 277ULN(+20%) 4S0ULL(+20%) CATIII 400ULN(+20%) 690ULL(+20%) CATII
Metering	Electric energy		Active energy : Class D Reactive energy (Class 2 accuracy)
Auxiliary power supply	ACDC 85-300V
Electromagnetic compatibility	power consumption ≤ 4W、 10VA
	Electrostatic discharge immunity class IV
	Surge (shock)immunity Class IV
Security	Power frequency withstand voltage		Between communication and signal input, AC4kV lmin
	Insulation resistance		Input and output terminals to casing >500MΩ
Communication	Interface and communication protocol		RS4S5 interfiace and Modbus RUT protocol
	Communication address range		Modbus RTU:1~247
	Baud rate		Support 1200bps-38400bps
Environment	Operating temperature		-40C~+70C
	Storage temperature		-40C~+80C
	Relative hummidity		≤95% (without condensation)
	Altitude		≤2000m, 5000m Only applicable to the power supply with the voltage range of AC/DC 85-265V and the voltage below 277/480V.
	Installation environment		Indoor use (dry location)
	IP rating		IP54(Front panel),IP30(Body)
	Pollution degree		Class 2
	Over voltege categories		OVC I11
Reference standard	UL		CAN/CSA C22.2 NO.61010-1-12 UL61010-1 CSA C22.2 No.61010-2-030 UL61010-2-030
	IEC EC		IEC 61010-1 IEC EN 61010-2-30
	CPA		GB/T17215.321-2021 GB/T17215.323-2022

Product Advantages

Multifunctionality: Supports four-quadrant energy measurement, harmonic analysis, demand statistics, event logging, etc., meeting diverse power monitoring needs.

High Accuracy: Voltage and current measurement error ±0.2%, energy metering meets Class D standards, ensuring data accuracy.

Flexible Installation: Offers multiple installation methods such as embedded and DIN rail mounting to adapt to different scenario requirements.

Safe and Reliable: Certified by UL, CE, etc., compliant with CAT III/CAT II safety standards, featuring overload protection and double insulation design.

Convenient Communication: Supports multiple protocols such as Modbus-RTU and DL/T 645-2007, compatible with RS485 and Ethernet communication, facilitating system integration.

Strong Expandability: Optional DI/DO and AO modules enable switch status monitoring and analog output, meeting customized needs. Suitable for industrial, commercial, and power systems, providing accurate power monitoring solutions.

Aaron Shi

Electrical Engineer Expert, Providing Service, consultant, product expert, professional manufacturer of energy efficiency management systemic solutions, and energy meters.

References

This is the first one.

The Benefits of Using MID-Certified Energy Meters in Industrial Applications

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