Iskra iMC740 Class S Multifunction Power Meter, 96 mm

iMC740 is the Iskra multifunction meter for permanent monitoring of single-phase and three-phase networks in a 96 mm square panel housing. It meets the class S requirements of EN 61557-12, samples at 32 kHz, and reports more than 140 quantities including harmonics and unbalance. This page lists the numbers printed in the Iskra data sheet and user manual.

Class S metering with network time sync and three ports

Four voltage and three current channels use automatic range selection up to 1000 VTRMS and 12.5 A, so a single hardware version covers low-voltage feeders directly and medium-voltage systems through transformers. Eight programmable energy counters track four quadrants with up to four tariffs, and 40 minimum and maximum values can be logged over averaging windows from one period to 256 periods.

Communication is configurable: COM1 is RS232/RS485 or Ethernet with USB, and a second port COM2 can be ordered as an I/O module. Modbus RTU, Modbus TCP and DNP3 L1 are supported, and NTP keeps the real-time clock aligned over Ethernet. A front SD slot (up to 2 GB) carries settings files and firmware upgrades.

Features stated in the data sheet

• Accuracy class S (0.2 %) per EN 61557-12; active energy class 0.5S or 0.2S; frequency 16 Hz to 400 Hz.
• Up to four inputs or outputs: analogue, digital, pulse, tariff, alarm or watchdog.
• EX104 extension unit adds four configurable analogue outputs (0.4 to 20 mA or 0 to 10 V).
• Universal power supply, multilingual display, MiQen set-up software.

Technical specification

Measurement data

Inputs, outputs and mechanics

Choosing options from the order code

The code iMC740 followed by seven letters selects the current connection (T through-hole or C screw terminal), RTC backup (C supercap, B battery), auxiliary supply, I/O module 1/2, I/O module 3/4, communication COM1 and nominal frequency. Module letters cover relay, bistable relay, analogue, pulse, digital, tariff and status functions, including analogue inputs in mA, V or temperature.

Four communication configurations exist: RS232/485 only, RS232/485 plus a second serial port, Ethernet and USB, or Ethernet and USB plus a second serial port. The galvanic separation between Ethernet and USB is 1 kV AC. Fixed or programmable values are not part of the code.

Installation and commissioning notes

The user manual describes the iMC7x0 family as a fixed panel instrument, not portable equipment. It recommends a 6 A maximum protection fuse for voltage inputs and a suitably marked external switch or circuit breaker for the auxiliary supply; the inrush can reach 20 A for less than 1 ms, so choose the breaker accordingly.

Route voltage wires away from current transformers to avoid crosstalk, remove the protection foil from the screen, and connect the functional earth terminal. Current terminals are wired from outside because of space limits.

Where this meter is used

General engineering note: class S accuracy with harmonic and unbalance data suits plant main incomers, generator and transformer feeders, and distribution boards that need permanent monitoring with alarms. Time-synchronised readings from several meters help to find the origin of a disturbance, as the data sheet explains.

In hot panel rooms, check the K55 class limit of 55 C against the temperature inside the cabinet.

Related Iskra items

The iMC750 adds an internal recorder, the iMC770 and iMC784A add Class A power-quality functions, and the iMC330 is a simpler three-phase multimeter. Browse the power meters category for the full family.

Notes for panels in Oman and the GCC

Oman’s low-voltage networks run at 50 Hz, so set the nominal frequency and connection type during commissioning. In hot switchrooms, check the panel’s internal temperature against the meter’s operating range.

Frequently asked questions

Which accuracy class does iMC740 meet?

The data sheet states class S (0.2 %) accuracy in compliance with EN 61557-12, with active energy class 0.5S or 0.2S.

Does iMC740 support Ethernet and Modbus TCP?

Yes. COM1 can be ordered as Ethernet and USB, and the protocols are Modbus RTU, Modbus TCP and DNP3 L1, plus NTP time synchronisation.

What is the front panel cut-out?

The required mounting hole is 92 mm x 92 mm in a 96 mm x 96 mm housing, 96.5 mm deep, weighing 550 g.

Can the meter output analogue signals?

Yes, through two-channel analogue output modules, and four more outputs with the EX104 extension unit.

Does Seven Star LLC act as an Iskra distributor?

No, we are an independent supplier in Muscat and supply Iskra items on request rather than acting as a Iskra channel partner.

Documents and quotation

Download the official Iskra datasheet and manual for iMC740 from this page. As an independent supplier based in Muscat, Seven Star LLC supplies Iskra items on request: use the quote form with the quantity you need. Check every value in the documents against your own specification before you order. Browse similar items in the category.