Siemens SENTRON PAC4220

Power monitoring device

This guide covers the wide-range-supply PAC4220, ordering code 7KM4220-0BA01-1EA0. Edge reads its native Ethernet interface without a serial module. The April 2025 manual, scoped from firmware 3.4.0, supplies the measurement offsets and security controls. Start with frequency and voltage, select the Float decoder against the display once, then extend the read-only poll.

Siemens SENTRON PAC4220 panel meter showing its phasor display and four front keys
  • Modbus TCP

Power monitoring device

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Compatibility

Compatible with EpiSensor Edge over Modbus TCP

Siemens documents native Ethernet, FC03/FC04 and two-register Float voltage, current, frequency and power values. Edge can read these over the protected site IP network.

Exact code 7KM4220-0BA01-1EA0, using manual L1V30827278B_RS-AC_005 from firmware 3.4.0 as the documented starting point. Record installed firmware and CT settings. One site check must select byte/word order against simultaneous frequency and voltage displays; the manual does not specify the ordinary Float word order.

Connect it with

For either built-in PAC4220 Ethernet port

  • Modbus
  • Edge
  • Platforms
Power monitoring device
Interface
Gateway
Edge
Output
SENTRON PAC4220PAC4220 Ethernet port
Protected EthernetSegmented LAN
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeModbus client + register map
Customer platformMQTT · API · files
Modbus TCP
Protected Ethernet
Runs locally
Optional onward data
Use the configured IP address, subnet and Modbus TCP port. Admit the Gateway address with the read-only allowlist role, retain the device’s hardware write protection and keep meter administration on the authorised network. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
7KM4220-0BA01-1EA0Two built-in Ethernet ports, 1 A/5 A CT inputs and the wide-range AC/DC supply.Direct Modbus TCP connection over Ethernet; no RS-485 module is needed.
7KM4220-1BA01-1EA0 / 7KM9300-0AM00-0AA0The first code is the separate extra-low-voltage DC meter variant. The second is the optional RS485 expansion module.Do not apply the low-voltage supply to the chosen meter. A serial route needs its installed module and separate serial configuration; the Ethernet route here does not use it.

Specifications

The exact wide-range supply code appears in both Siemens’ product record and the retained April 2025 manual. That manual covers firmware from 3.4.0; it is not proof of the firmware installed at a site. PAC4220 is a separate generation from PAC4200, so use its own configuration and register documentation.12

Exact supply variant
7KM4220-0BA01-1EA0: 95–250 VAC ±10% or 110–270 VDC ±10%, maximum 28 VA / 6 W on AC and 6 W on DC.12
Measurement inputs
CT inputs rated for 1 A or 5 A; nominal 400 V L-N / 690 V L-L upper range under IEC conditions. Configure CT/VT ratios and wiring before use.1
Accuracy
Total active energy class 0.2S to IEC 62053-22; voltage and current class 0.2 to IEC 61557-12. External CT quality affects the installed measurement.12
Native communications
Two RJ45 Ethernet ports with an internal switch, 10/100 Mbit/s. Modbus TCP is native; RS485 is an optional expansion module.1
Installation envelope
96 × 96 mm panel instrument. Front IP65, rear IP20; enclosed dry-room installation, −25 to +55 °C and altitude up to 2000 m. Follow the manual’s temperature-dependent humidity limits.1

Interface

Documented measurements and integration boundaries for SENTRON PAC4220.

  • The April 2025 table lists two-register Float values: L1-N voltage offset 1 in V, L1 current offset 13 in A, line frequency offset 55 in Hz and total active power offset 65 in W. FC03 and FC04 are documented.
  • Read each complete value from its listed start offset. A read that starts on the second word or ends inside a multi-register quantity can produce a Modbus exception.
  • The four-register double energy values, such as active energy import tariff 1 at offset 801, exceed the current Edge Modbus read width. Do not read half a counter or relabel Float electrical readings as billing energy.

Assessment

PAC4220 wide-range code 7KM4220-0BA01-1EA0, April 2025 documentation from firmware 3.4.0, complete two-register Float values.

InteroperabilityWell supported
Native Ethernet and documented FC03/FC04 measurement offsets give a direct connection. Select the Float byte/word arrangement against the display because the manual does not state it.1
AccuracySupported with conditions
Siemens specifies class 0.2S total active energy and CT-based measurements. CT quality and ratios matter; the proposed Edge point set uses complete two-register electrical values, not four-register energy counters.12
SecuritySupported with conditions
The manual documents an IP allowlist with a read-only role and physical hardware write protection. Configure both for the monitoring client and protect the site network; ordinary Modbus TCP is not an encrypted application session.1
ReliabilitySupported with conditions
The meter has a documented wide-range supply and gapless measured-value acquisition. Its Ethernet interface updates instantaneous values in about 500 ms. Match polling to that rate and verify stale-data handling.1
RuggednessSupported with conditions
Front IP65 and rear IP20 apply to an enclosed dry-room panel installation. The −25 to +55 °C envelope, altitude and humidity limits need to match the installed cabinet.1
ScalabilitySupported with conditions
The internal two-port Ethernet switch supports line cabling and the allowlist accepts up to ten addresses or ranges. Budget the polling traffic and upstream network; two ports do not establish redundant networking.1
LifecycleSupported with conditions
An exact product record and firmware-scoped public manual support replacement planning. The manual documents firmware updates and no downgrades for security reasons; retain the installed version and configuration rather than applying an assumed generation-wide decoder.12

Setup

Select the frequency decoder with one site comparison

Appendix A.1.4 table A-1 lists line frequency at offset 55, two registers, Float, in Hz. This read-only request follows that literal offset.

Read function
FC03 Read Holding Registers; FC04 is also documented for the table.
Start offset and length
55 decimal = 0037h; 2 registers
Request PDU
03 00 37 00 02
Conditional synthetic example
If the returned bytes are 42 48 00 00, ABCD Float32 decodes to 50.0 Hz. If they are 00 00 42 48, CDAB gives 50.0 Hz. These are decoder examples, not an OEM order specification.
Acceptance
Select the order that matches simultaneous frequency and voltage displays. Retain four bytes per reading and use the engineering unit directly.

Acceptance: The PDU uses the published function, offset and width. The response examples are calculated Float32 vectors, not a Siemens response capture or a fixed-order claim. A Modbus TCP client adds the transaction header and unit identifier.

  1. Confirm the supply and measuring circuit

    Have the authorised installer match the full ordering code, supply, CT secondary rating and wiring diagram. Apply the manufacturer’s isolation and CT-secondary short-circuiting precautions before wiring changes.

  2. Allow only the monitoring client

    Read the configured IP address and port locally. Add the Gateway address to the Modbus TCP allowlist with the read-only role. Hardware write protection applies to both the display and communication interface; keep it enabled for monitoring.

  3. Read one complete frequency value

    Use the manual’s frequency offset 55, hexadecimal 0037, with FC03 and a length of two registers. Preserve the returned four bytes. Do not send a 3xxxx/4xxxx display notation or split the value.

  4. Select the Float order against the display

    The table says Float but does not state ordinary measurement byte/word order. Decode the returned bytes with the supported Float32 arrangements and compare with simultaneous frequency and L1-N voltage displays. Retain the one matching order for the point set; do not assume a PAC4200 decoder or invent an integer scale.

Common questions

Is the RS485 module included in this Ethernet route?
No. The meter has two native Ethernet ports. The manual identifies 7KM9300-0AM00-0AA0 as an optional RS485 expansion module; a Modbus RTU route would need that installed hardware and its own serial setup.1
Can the low-voltage supply be used on this code?
No. Siemens assigns the 24–48 VDC ±25% supply to 7KM4220-1BA01-1EA0. This guide’s 7KM4220-0BA01-1EA0 has the distinct wide-range AC/DC supply. Match the nameplate before connection.12
Can the settings be locked while Edge reads?
Yes. The manual documents a read-only Modbus TCP allowlist role and hardware write protection. The display PIN alone protects local operation; it is not a substitute for the network allowlist and device write protection.1

Sources

  1. PAC4220 equipment manual, April 2025, from firmware 3.4.0 (opens in a new tab) (PDF) Siemens
  2. 7KM4220-0BA01-1EA0 official product record (opens in a new tab) Siemens

Further reading

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