ROOTECH

Digital Power Meter

Display
Shows real–time measurement data on the FND display screen
Voltage
Line–to–neutral voltage, Line–to–line voltage, Fundamental frequency, Harmonics, Phasor diagram, THD¹
Symmetrical components(positive–, negative–, zero–sequence),Voltage unbalance based on symmetrical components, voltage unbalance according to the NEMA standard, Residual voltage
Current
Phase current, Fundamental frequency, Harmonics, Phasor diagram, THD¹, TDD²
Symmetrical components(positive–, negative–, zero–sequence), Current unbalance based on symmetrical components, Current unbalance according to the NEMA standard, Residual current
Power
Active, Reactive, and Apparent power
Power Quality
Voltage / Current harmonics	Magnitude of each harmonic up to the 50th order, THD, Current TDD, Crest factor, K–factor
Unbalance(voltage/current)	Unbalance according to the NEMA standard, Negative–/zero–sequence unbalance based on symmetrical components
Phasor	Voltage and current phasor
Waveform	Voltage and current waveforms
	One cycle of a waveform(64 samples/cycle)
Events
Detects Fuse fail, Phase open, and Blackout events
Detects Over–temperature events
Max. number of event logs	50
Aggregation of Measurement Data
Aggregation intervals	Fixed intervals		Supports 6 fixed intervals(1 and 5 seconds, 1 and 5 minutes, 1 and 6 hours)
Measurement data	Average value		Average value of the values measured for 0.2 seconds
	Max/Min value		Max/Min value of the values measured for 0.2 seconds
IO Modules(selectable when ordering the basic module)
DC module: 1 DC voltage input channel,2 DC current input channels,4 digital input channels,1 digital output channel
DIO module: 8 digital input and 2 digital output channels
DI module: 12 digital input channels		DO module: 6 digital output channels
AI module: 6 analog input channels		AO module: 6 analog output channels
A4D2 module: 4 analog output and 2 digital output channels		A2D4 module: 2 analog output and 4 digital output channels
RTD module: 3 RTD input channels		ELD module: 6 leakage current input channels and 1 digital output channel
External Communication with the Host System
Ethernet communication³	Communicates with the host system using the Modbus TCP protocol at 100 mbps
	Transfers a large amount of measurement data to the host system at high speeds
	The 2 ports allow for Ethernet connection between Accura 3550 devices.
	Wiring: Star, Daisy–chain, Ring connections (RSTP support⁴)
RS–485 communication	Communicates with the host system using the Modbus RTU protocol⁶ at 1,200 – 115,200 bps
Power Supply
Power supply voltage	AC 100 – 240 V 50/60 Hz, DC 100 – 300 V
Power Consumption
IO module not connected	6 W
2 IO modules connected	12 W

1. THD(Total Harmonic Distortion). Voltage THD:

, Current THD:

:fundamental voltage,

:fundamental current
2. TDD(Total Demand Distortion). Current TDD:

:peak demand current
3. The built–in switch allows for Ethernet connection between Accura 3550 devices without a separate external switch.
4. RSTP(Rapid Spanning Tree Protocol), IEEE 802.1D–2004
5. Up to 16 devices can be connected to each bus at 115,200 bps.

IO Modules

Accura 3550 comes with various IO modules that can be easily connected to the back of the device. Up to four modules can be attached regardless of connection sequence, and the same types of modules can be redundantly connected.
Model	Number of Channels		Specifications	Power Consumption
Accura 3550 DC module	DC voltage input	1	0 – 200V	2.0 W
	DC current input	2	–100 – 100 mV(shunt resistance required)
	Digital input	4	Internal DC 24 V power supply(Self excitation), redundant circuits
	Digital output ¹	1	Dry contact(external excitation)
Accura 3550 DIO module	Digital input	8	Internal DC 24 V power supply(Self excitation), redundant circuits	2.2 W
Accura 3550 DIO module	Digital output ¹	2	Dry contact (external excitation)	2.2 W
Accura 3550 DI module	Digital input	12	Internal DC 24 V power supply(Self excitation), redundant circuits	3.2 W
Accura 3550 DO module	Digital output ¹	6	Dry contact (external excitation)	0.4 W
Accura 3550 AI module	Analog input	6	DC 0 – 20mA	0.6 W
Accura 3550 AO module	Analog output²	6	DC 4 – 20mA, DC 0 – 20mA	3.6 W
Accura 3550 A4D2 module	Analog output²	4	DC 4 – 20mA, DC 0 – 20mA	2.6 W
Accura 3550 A4D2 module	Digital output ¹	2	Dry contact(external excitation)	2.6 W
Accura 3550 A2D4 module	Analog output²	4	DC 4 – 20mA, DC 0 – 20mA	1.7 W
Accura 3550 A2D4 module	Digital output ¹	4	Dry contact(external excitation)	1.7 W
Accura 3550 RTD module	RTD input	3	PT100, PT1000 4–wire, 3–wire, 2–wire module	0.8 W
Accura 3550 ELD module	Leakage current input	6	AC 0 – 2,000mA	0.7 W
Accura 3550 ELD module	Digital output ¹	1	Dry contact(external excitation)	0.7 W
Operation
Digital input detection cycle	1 msec
Analog input detection cycle	1 msec
Analog output(measurement) control cycle	200 msec
Analog output(communication) control cycle	20 msec
Power Supply
Receives power from Accura 3550

1. DO channels support latches, a single pulse, periodic pulses, and countable pulses.
2. AO channels output various electrical quantities measured by the device or communication command values by converting them into values between 0 and 20 mA.

Digital Power Meter

Voltage Input
Port name	V1, V2, V3, VN
Connector type	Terminal block¹
Wire specification	1 – 2.5 mm²(18 – 14 AWG), copper or aluminum
Wire temp rating	Above 70 ˚C
Measurement catagory	III
Withstand voltage	AC 2,000 V RMS, 60 Hz for 1 minute
Impedance	10 MΩ/phase
Burden	0.01 VA/phase @ 220 V
Wiring method	3P4W, 3P3W, 1P3W, 1P2W
Current Input
Port name	1S, 2S, 3S ports on the power supply side, 1L, 2L, 3L ports on the load side(internal busbar)
Connector type	Terminal block²
Wire specification	2.1 – 6.0 mm²(14 – 10 AWG), copper or aluminum
Wire temp rating	Above 70 ˚C
Rating Input	5 A nominal/10 A full scale 3~ continuous, per UL61010, 100A for 1 second(thermal)
Burden	0.01 VA/phase @10 A
Basic Measurement
Frequency measurement	Measuring range	42 – 69 Hz(50/60 Hz)
Basic measurement	Measurement cycle(gapless)	0.2sec(12 cycles @60Hz, 10 cycles @50Hz)
Voltage	Sampling	512 samples/cycle
	Measuring range(accuracy guaranteed)	35 – 300 V Line–to–line
		60 – 500 V Line–to–neutral
	Accuracy	±0.2 % Reading
	Minimum measured value	5 V Line–to–neutral(based on the secondary voltage of the PT when external PTs are connected)
	Measurement data	Line-to–neutral, Line–to–line voltage
		Fundamental, Harmonics(up to the 50th order)³
		Phasor, THD
		Symmetrical components(positive–, negative–, zerosequence components)
		Unbalance according to symmetrical components/ the NEMA standard
Residual voltage	Measuring method	Calculation of the sum of sampled three–phase line–to–neutral voltages
	Measurement data	RMS, Fundamental
	Accuracy / Operating range	±0.2% Un⁴ / Up to 300 V Line–to–neutral
Current	Sampling	256 samples/cycle
	Measuring range(accuracy guaranteed)	1 % In – 200 % In⁵
	Accuracy	±0.2% Reading
	Minimum measured value	0.1 % In
	Measurement data	Phase current
		Fundamental, Harmonics(up to the 50th order)
		Phasor, THD, TDD
		Symmetrical components(positive–, negative–, zerosequence components)
		Unbalance according to symmetrical components/ the NEMA standard
Residual current	Measuring method	Calculation of the sum of sampled three–phase currents
	Measurement data	RMS, Fundamental
	Accuracy / Operating range	±0.2% In / Up to 200 % In of phase current
Power	Accuracy of active power	IEC 61557–12 Class 0.5
	Accuracy of reactive power	IEC 61557–12 Class 1
	Accuracy of apparent power	IEC 61557–12 Class 0.5
Energy	Active	Accuracy	IEC 62053–22 Class 0.5S
		Type of energy	Received, Delivered, Net, Sum(total) energy
	Reactive	Accuracy	IEC 62053–24 Class 0.5S
		Type of energy	Energy in quadrant 1, 2, 3 and 4
	Apparent	Accuracy	IEC 61557–12 Class 0.5
Demand	Current, Apparent power⁶, Active power	Demand, Peak demand, Predicted demand⁷
	Demand time setup	Demand time = Demand sub–interval * the number of demand sub–intervals
IO Module Control
Module control	Maximum number of connectable modules: 2
	Automatically detects the connection status of modules and performs the module ID setup function
	Collects measurement and status data from connected IO modules
External Communication with the Host System
Ethernet communication	Protocol	Modbus TCP Protocol
	Port	2 ports, Ethernet switching⁸
	Connector type	RJ45 connector
	Communication cable	Ethernet cable Cat 5e FTP, STP, SFTP⁹
	Cable length	Up to 100 m
	Communication speed	100 Base–TX(100 Mbps/Full Duplex)
	Wiring mode	Star, daisy chain, ring topology(RSTP support)¹⁰
	Max. number of connected modules	20
RS–485 communication	Protocol	Modbus TCP Protocol
	Port	1port/Ta, Tb
	Connector type	Push In conductor	0.13 – 1.5 mm² (26 – 16 AWG)
	Communication cable	UL2919 RS–485 1P/2P 24 AWG
	Cable length	Up to 1,219 m (4,000 ft)
	Communication speed	1,200 – 115,200 bps¹¹
	Max. number of connected modules	32 per bus¹¹
Power
Port name	L+, N–
Connector type	Screw–type terminal(pluggable)
Wire specification	0.2 – 4.0 mm² (24 – 12 AWG), copper or aluminum
power supply voltage(Us)	AC 100 – 240 V 50/60Hz, DC 100 – 300 Vdc
Frequency	50/60 Hz
Operating voltage range	0.9 x Us – 1.1 x Us
Withstand voltage	AC 2,000 V RMS, 60Hz for 1 minute
Operating environment	Pollution degree 2
Power Consumption	6 W	IO module not connected
	12 W	2 IO modules connected
Inrush current¹¹	Peak 22 A, duration less than 1 msec(AC 220 V)
	Peak 11 A, duration less than 200 μsec(DC 110 V)

1. The maximum tightening torque of the terminal screws of the barrier–type terminal is 1.24 Nm (13 kgf–cm, 11 Ibf–in).
2. The maximum tightening torque of the terminal screws of the barrier–type terminal is 1.4 Nm (14 kgf–cm, 12 Ibf–in).
3. It indicates the harmonic components of the line–to–line voltage in 3P3W mode and the line–to–neutral voltage in 3P4W mode.
4. The rated voltage Un is 280V Line–to–Neutral.
5. The rated current In is 5 A.
6. For active power demand, Received or Net active power can be selected.
7. Peak demand is calculated based on thermal demand. The response time for thermal demand can be set up.
8. The built–in Ethernet switch allows for Ethernet connection between Accura 3550 devices, without a separate external switch.
9. FTP(Foiled Shield Twisted Pair), STP(Braided Shield Twisted Pair), SFTP(Braided Foiled Shield Twisted Pair)
10. RSTP(Rapid Spanning Tree Protocol), IEEE 802.1D–2004.
11. Up to 16 devices can be connected per bus at 115,200 bps.
12. When installing a fuse at the voltage line, it is recommended to use a fuse above 2A/500V due to inrush current.

General Specifications of IO Modules

DC 0–20mA Analog Input
Item	Description
Connector type	Screw–type terminal(Pluggable)
Wire specification	0.21 – 3.5 mm² (24 – 12 AWG), max 0.5 Nm (5 kgf–cm, 4 Ibf–in)
Input type	Dry contact(external excitation)
Input type	DC current 0 – 20 mA
Internal input resistance	150 Ω
Accuracy	±0.5 % Full Scale	Full Scale: 20 mA
DC 0–20mA Analog Output
Item	Description
Connector type	Screw–type terminal (Pluggable)
Wire specification	0.21 – 3.5 mm² (24 – 12 AWG), max 0.5 Nm (5 kgf–cm, 4 Ibf–in)
Output type	DC Current 0 – 20 mA
Allowable load resistance	Less than 450 Ω
Accuracy	±0.5 % Full Scale	Full Scale: 20 mA
Digital Input
Item	Description
Connector type	Screw–type terminal(Pluggable)
Wire specification	0.21 – 3.5 mm² (24 – 12 AWG),max 0.5 Nm (5 kgf–cm, 4 Ibf–in)
Input type	Internal DC 24 V power supply(self–excitation)
Carried current	1st channel : 10 mA, other channels: 5 mA
Insulation	Max. AC 2000 V for 1 minute
Minimum pulse width	10 msec
Digital Output
Item	Description
Connector type	Screw–type terminal (Pluggable)
Wire specification	0.21 – 3.5 mm² (24 – 12 AWG), max 0.5 Nm (5 kgf–cm, 4 Ibf–in)
Output type	Dry contact(external excitation)
Maximum Rating	AC/DC 240 V 350 mA (max. 1 A)¹
Insulation	Max. AC 2,000 V for 1 minute
Output signal type	Latch, pulse, energy pulse
Minimum pulse cycle	20 msec
Minimum pulse width	10 msec

1. It indicates the Peak AC or DC value. Max. 1 A indicates current flowing once during a current–carrying time of 100 ms.

Specifications of Individual IO Modules

Accura 3550 DC Module
DC voltage/current input
Number of channels	3
Port name	I_OUT+ I_OUT– / I_BAT+ I_BAT– / V_DC+ V_DC–⁵
DC Shunt resistance	Max. DC 100 mV
DC Voltage	Max. DC 200 V
Accuracy	±0.5 % Full Scale
Digital Input			Digital Output
Number of channels	4(redundant circuits per channel)¹		1
Port name	DI₁ DI₂ DI₃ DI₄ DI_G²		DO DO_G
Power Consumption	2.0 W
Accura 3550 DIO Module
Digital Input			Digital Output
Number of channels	8 (redundant circuits per channel)¹		2
Port name	DI₁ DI₂ DI₃ DI₄ DI_G / DI₅ DI₆ DI₇ DI₈ DI_G²		DO₁ DO_1G / DO₂ DO_2G³
Power Consumption	2.2 W
Accura 3550 DI Module
Digital Input
Number of channels	12 (redundant circuits per channel)¹
Port name	DI₁ DI₂ DI₃ DI₄ DI_G / DI₅ DI₆ DI₇ DI₈ DI_G / DI₉ DI₁₀ DI₁₁ DI₁₂ DI_G²
Power Consumption	3.2 W
Accura 3550 DO Module
Digital Output
Number of channels	6
Port name	DO₁ DO_1G / DO₂ DO_2G / DO₃ DO_3G / DO₄ DO_4G / DO₅ DO_5G / DO₆ DO_6G³
Power Consumption	0.4 W
Accura 3550 AI Module
Analog Input
Number of channels	6
Port name	AI₁ AI_1G / AI₂ AI_2G / AI₃ AI_3G / AI₄ AI_4G / AI₅ AI_5G / AI₆ AI_6G⁴
Power Consumption	0.6 W
Accura 3550 AO Module
Analog Output
Number of channels	6
Port name	AO₁ AO_1G / AO₂ AO_2G / AO₃ AO_3G / AO₄ AO_4G / AO₅ AO_5G / AO₆ AO_6G
Power Consumption	3.6 W
Accura 3550 A4D2 Module
Analog Output			Digital Output
Number of channels	4		2
Port name	AO₁ AO_1G / AO₂ AO_2G / AO₃ AO_3G / AO₄ AO_4G		DO₁ DO_1G / DO₂ DO_2G³
Power Consumption	2.6 W
Accura 3550 A2D4 Module
Analog Output			Digital Output
Number of channels	2		4
Port name	AO₁ AO_1G / AO₂ AO_2G		DO₁ DO_1G / DO₂ DO_2G / DO₃ DO_3G / DO₄ DO_4G³
Power Consumption	1.7 W
Accura 3550 RTD Module
RTD Analog Input
Number of channels	a₁ A₁ B₁ b₁ / a₂ A₂ B₂ b₂ / a₃ A₃ B₃ b₃
RTD sensor	PT100, PT1000
Wiring method	4W, 3W, 2W
Accuracy	±0.5 % Full Scale		Range: –100 to 200 °C, Full Scale: 200 °C
Power Consumption	0.8 W
Accura 3550 ELD Module
ZCT Analog Input			Digital Output
Number of channels	6		1
Port name	Z₁ Z_1G / Z₂ Z_2G / Z₃ Z_3G / Z₄ Z_4G / Z₅ Z_5G / Z₆ Z_6G⁶		DO, DOG
Leakage current input	Voltage output type ZCT 200 mA/100 mV @ 1.2 kΩ Burden⁷
Accuracy	±0.5 % Full Scale	200mA/100mV, Range: 0 – 2 A, Full Scale: 2 A
Power Consumption	0.7 W

1. Each channel features redundant circuits. Thus when two inputs differ, the module processes the event as a redundancy error
and provides maintenance notifications
2. The DIG port is internally connected and is the common ground port of all channels.
3. Each DO channel is electrically insulated.
4. The inputs of each channel features differential inputs, and the common–mode voltage should be less than 2 V.
5. The inputs of each channel features differential inputs, and the common–mode voltage should be less than 200 V.
6. The inputs of each channel features differential inputs, and the common–mode voltage should be less than 2 V.
7. The internal resistance(default: 1.0 kΩ) and burden resistance of the ZCT(default: 1.2 kΩ) can be set up.

General Specifications

Environmental Conditions
Installation location	Indoors
Operating temperature	–20 to 70℃(–4 to 158℉)
Safe operating temperature ¹	–20 to 65℃(–4 to 149℉)
Storage temperature	–40 to 85℃(–40 to 185℉)
Operating humidity	5 – 95%(non–condensing)
Operating altitude	Up to 2,000 m
General
Warranty Period	2 years