Modbus TCP meters

Modbus TCP meters

Modbus TCP meters allow for more flexibility in the installation. Since they use local network connectivity usually both wired and wireless options are available depending on the installation needs. The installation is also faster, since the meters need less space and work with the electrical cabinet, as the measurements are done via CT clamps that connect to the meter. It also allows for load balance in situations, where power cables have been prepared in advance, without preparing any data cables, or if the distances from electrical cabinet to the charger location are very long.

Shelly PRO-3EM

Description

Shelly Pro 3EM is a DIN-rail-mounted, three-phase energy meter that can operate locally over LAN or Wi-Fi, or connect to cloud and home automation systems. The device can be remotely accessed, configured, and monitored through the same network infrastructure, and its built-in web interface allows users to monitor and adjust settings.

Wiring diagram

User and safety guide

Shelly Pro 3EM user and safety guide

Resources

Manufacturers documentation page

Certificates and conformity declarations

EU

UK

AU and NZ

Technical data

Type	Value
Physical
Size (HxWxD):	94x19x69 ±0.5 mm / 3.70x0.75x2.71 ±0.02 in
Weight:	62 ±1 g / 2.19 ±0.05 oz
Mounting:	DIN rail
Screw terminals max torque:	0.4 Nm / 4.43 lbin
Conductor cross section:	0.5 to 2.5 mm² / 20 to 14 AWG (solid, stranded, and bootlace lugs)
Conductor stripped length:	6 to 7 mm / 0.24 to 0.28 in
Shell material:	Plastic
Color:	White
Environmental
Ambient temperature:	-20 °C to 40 °C / -5 °F to 105 °F
Humidity:	30 % to 70 % RH
Max. altitude:	2000 m / 6562 ft
Electrical
Power supply voltage AC:	100 - 260 V, 50/60 Hz
Power supply voltage DC:	N/A
Power consumption:	< 3 W
External protection:	Tripping characteristic B or C, 16A max. rated current, min. 6 kA interrupting rating, energy limiting class 3
Sensors, meters
Internal-temperature sensor:	Yes
Voltmeters (RMS for each phase):	100 - 260 V
Voltmeters accuracy:	±1 %
Ammeters (RMS via CT for each phase and the Neutral):	0 - 120 A
Compatible CT	CT 120A
Ammeters accuracy:	±1 % (2 - 120 A), ±2 % (1 - 2 A), ±5 % (0 - 1 A)
Power and energy meters:	Active and apparent power Active and apparent energy Power factor Fundamental active and fundamental reactive energy
Channel-to-channel calibration minimum load	500 W per channel
No load threshold:	30 VA per channel
Measurement data storage:	At least 60 days of 1 min data resolution
Data export:	CSV for PQ recorded values JSON format export through RPC
Radio
RF band:	2400 - 2495 MHz
Max. RF power:	<20 dBm
Wi-Fi protocol:	802.11 b/g/n
Wi-Fi Range:	Up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors (Depends on local conditions)
Bluetooth Protocol:	4.2
Bluetooth Range:	Up to 10 m / 33 ft indoors and 30 m / 100 ft outdoors (Depends on local conditions)
MCU
CPU:	ESP32-D0WDQ6
Flash:	16 MB
Firmware capabilities
Webhooks (URL actions):	20 with 5 URLs per hook
Scripting:	Yes
MQTT:	Yes
CoAP:	No

EASTRON SEM 3 WL

Description

Eastron SEM3 is a new generation din rail mounted energy meter, equipped with Wi-Fi and RS485 connectivity. The meter can be used as 1x 3phase energy meter or 3 individual single phase energy meter. In single phase mode, 3 external CTs can be set with different CT ratio for three independent loads.

Wiring diagram

Wi-Fi Configuration

You may find the installation instructions on page 11 of the official manual.

Electrical, Mechanical, Environmental, EMC and Safety Characteristics

Electrical Characteristics
Type of Measurement	RMS, Including Harmonics, on Three Phase AC System (3P+N)
Measurement Accuracy	Power	± 1% IEC 61557-12 Class 1
	Active Energy	± 1%
	Reactive Energy	± 2%
	Frequency	± 0.2%
	Current	± 0.5% (4A to 120A) ± 1% (1A to 4A) ± 3% (0.06A to 1A)
	Voltage	± 0.5%
	Power Factor	± 0.1
Data Update Rate	Active Power: 50ms (RS485), 100ms (Wi-Fi)
Input-Voltage	Un	3*230V L-N / 3*400V L-L
	Working Voltage Range	90 to 277 V ac L-N 156 to 480 V ac L-L
	Frequency Range	50/60Hz
Mechanical Characteristics
Weight	≈100g (SEM3)
IP Degree of Protection (IEC 60529)	IP51 Front Display IP20 Whole Meter
Dimensions (DxHxW)	68.5*90*19mm
Mounting	DIN Rail 35mm
Material of Meter Case	Self-extinguishing UL 94 V-0
Mechanical Environment	M1
Environmental Characteristics
Operating Temperature	-40°C to +70°C
Storage Temperature	-40°C to +85°C
Humidity Rating	≤95% RH, non-condensing
Pollution Degree	2
Altitude	Up to 2000m
Vibration	10Hz to 50Hz, IEC 60068-2-6
Electromagnetic Compatibility
Electrostatic Discharge	IEC 61000-4-2
Immunity to Radiated Fields	IEC 61000-4-3
Immunity to Fast Transients	IEC 61000-4-4
Immunity to Impulse Waves	IEC 61000-4-5
Conducted Immunity	IEC 61000-4-6
Immunity to Magnetic Fields	IEC 61000-4-8
Immunity to Voltage Dips	IEC 61000-4-11
Radiated Emissions	EN55032 Class B
Conducted Emissions	EN55032 Class B
Safety
Measurement Category	Per IEC61010-1 CAT III
Current Inputs	Require External Current Transformer for Isolation
Over-voltage Category	CAT III
Protective Class	II
Communications
Interface 1	RS485 Port
Interface 1 Protocol	MODBUS RTU
Communication Address	1 to 247
Transmission Mode	Half Duplex
Data Type	Floating Point
Transmission Distance	1000m Maximum
Transmission Speed	2400/4800/9600/19200/38400/115200bps
Parity	NONE (Default) / ODD / EVEN
Stop Bits	1 or 2
Response Time	<50 ms
Interface 2	Wi-Fi
Interface 2 Protocol	MODBUS TCP
Data Type	Floating Point
RF Band	2.4 GHz to 2.5 GHz
Max. RF Power	<20 dBm
Wi-Fi Protocol	802.11 b/g/n
Wi-Fi Range	Up to 30m / 100ft indoors and 50m / 160ft outdoors (Depends on local conditions)