Carlo Gavazzi EM340 S1 X

Compatibility

Compatible through Modbus RTU

Manufacturer-documented serial read path; not physical device validation or a built-in mapping.

Exact EM340DINAV23XS1X, AV2 direct input and S1 RS-485. The current product page links protocol version 2 revision 17 (2021); this is a document revision, not the installed firmware. Record firmware and serial number. The July 2026 datasheet identifies updated units from serial 2026150000A and changes the read-command limit from 50 to 125 words. The two-register example avoids that boundary and the older protocol’s inconsistent 20/50-word descriptions. No physical validation or automatic template is claimed; reject the finite overflow marker before scaling.

Connect it with

• 
  Modbus Interface ZMB-3X
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• 
  Gateway ZGW-20
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Models

Specifications

For a circuit within its direct connection current rating, EM340 avoids external CT selection and ratios. The full order code matters: AV2 fixes the input range, S1 supplies RS-485, and the final X is not the MID option. The 2026 datasheet also distinguishes new production from older meters under the same model name.^2, 4

Exact order

EM340DINAV23XS1X: AV2 input, three-phase system, self powered, S1 RS-485, standard X option.⁴

Electrical input

Direct 5(65) A; nominal 120–230 V L-N / 208–400 V L-L. No external CT input on this version.⁴

Wiring systems

Three-phase three- or four-wire and two-phase three-wire configurations listed for the X option.²

Energy

Import/export active and reactive energy; class 1 active energy. The X option is explicitly not MID certified.²

Serial interface

Modbus RTU on RS-485; address 1–247; configurable speed, parity and stop bits. One-second data refresh.²

Generation boundary

Serial 2026150000A begins the June 2026 update. Read-command limit: 125 words for updated units, 50 for earlier units; this guide reads only two.²

Mounting and protection

Three DIN modules, 54 × 90 × 63 mm; front IP51, terminals IP20; X-option operation −25 to +65 °C indoors under the stated humidity limit.²

Interface

Documented measurements and integration boundaries for EM340 S1 X.

• Phase-neutral voltage starts at physical address 0x0000: two 16-bit registers forming a signed 32-bit value, scale 0.1 V, low word first.
• Phase current at 0x000C uses 0.001 A, while active power at 0x0012 uses 0.1 W. Do not reuse one multiplier for all quantities.
• The grouped map provides separate total import and export energy. Measurement mode A combines direction; mode B preserves bidirectional behaviour.
• Overflow code 0x7FFFFFFF arrives as words FFFF 7FFF. Reject it before applying the multiplier.
• The protocol also documents higher-resolution energy totalizers; select the corresponding address, width and resolution instead of changing the multiplier on the older counter.

Setup

1. Confirm the complete code and production generation

   Record EM340DINAV23XS1X, serial number and firmware. The current datasheet distinguishes updated units from serial 2026150000A. Confirm the actual direct-connected circuit is within the AV2 voltage and 65 A input limits; EM330 CT settings do not belong to this model.

2. Choose the energy meaning before reading totals

   Check the wiring-system setting and measurement selection. For the X option, mode A treats power direction as positive; mode B provides bidirectional import/export behaviour. Select the intended mode through the authorised commissioning process, then retain it with the point-list documentation.

3. Match serial settings and termination

   Read the configured Modbus address, speed, parity and stop bits from the meter and match them in Edge. Follow the manufacturer’s RS-485 wiring. The protocol uses terminal T to terminate the final instrument; do not apply termination at every meter.

4. Read two words at physical address zero

   For L1-N voltage, send FC03 or FC04 to physical address 0x0000 with quantity 2. The printed reference 300001 is not the PDU address. Decode signed INT32 with low word first and high byte first inside each word, then divide by 10.

5. Reject overflow and compare before expanding

   Treat raw 0x7FFFFFFF as overflow, not an enormous valid voltage. Compare the decoded result with the meter display. Add current, power and energy with their own map rows, and compare an energy delta. Keep resets and configuration writes outside this monitoring path.

Common questions

Is EM340 a CT-input meter?

No. The AV2 EM340 specified here measures the load directly up to 65 A. EM330 is the CT-input sibling in the shared protocol document. A common register layout is not permission to connect external CTs to the EM340 current path.²

Why is export energy not behaving as expected?

The X option supports measurement selection A or B. Mode A integrates power without direction, while B provides bidirectional behaviour. Check that selection and the actual wiring before interpreting separate imported and exported totals.¹

Should I enter 300001 as the start address?

No. The table’s physical address is the value included in the request: 0x0000 for L1-N voltage. Its six-digit Modicon reference names the input-register convention. Both FC03 and FC04 are documented for the same measurements.¹

Can every EM340 read 125 registers at once?

No. The July 2026 datasheet gives 125 words for updated production, while Annex A gives 50 words for earlier units. The older protocol also has inconsistent 20/50-word limit text. The two-word check stays below every stated limit; qualify larger reads against the actual generation.²

Why is no ready-made template offered on this exact guide?

The overflow code is a finite signed integer, so a normal numeric decoder would turn it into a misleading measurement. A prepared import needs explicit sentinel handling and exact-generation qualification. The broader family download is not physical validation of this exact unit.¹