Siemens SENTRON PAC1200

Compatibility

Compatible with EpiSensor Edge over Modbus TCP

The PAC1200 is compatible with EpiSensor Edge over Modbus TCP: the 7KT1261 Data Manager runs a Modbus TCP server on port 502, and Siemens documents Read Holding Registers, zero-based register numbers, most-significant-word-first values, the register areas and worked conversions for total imported power and energy.

PAC1200 systems with the 7KT1261 Data Manager, sensor bars 7KT1233, 7KT1236, 7KT1238 and 7KT1242 and sensors 7KT1254 and 7KT1255, using the register specification in equipment manual 2514374107_RS-AC_005 (01/2026, firmware 2.1.0) as a best-effort starting point. Registers beyond the two Siemens works through come from Siemens' register table or the list in the Data Manager's web interface. Site check: compare the first power read with Active power (+) in the Data Manager app. Systems documented only in the 2016 system manual and the Data Manager's RS485 register output are outside this guide. Read-only monitoring.

Connect it with

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Models

Specifications

The Data Manager measures voltage and current on the three phases of the incoming supply. The sensor bars measure only current in each outgoing circuit, and the Data Manager calculates each sensor's power from that current and the voltage of the phase the sensor is assigned to. Correct phase assignment in the Sensors app is therefore part of the measurement, not just labelling.¹

Components

Data Manager 7KT1261; sensor bars 7KT1233, 7KT1236, 7KT1238 and 7KT1242 with three, six, nine or twelve slots; sensors 7KT1254 (40 A) and 7KT1255 (63 A); starter kits 7KT1224 and 7KT1225.^1, 2

Supply

From L1 and N: 230 V AC ±10 % at 50 Hz or 110 V AC ±10 % at 60 Hz; 12.5 VA.¹

Measurement

110 to 230 V AC ±10 %, 50 or 60 Hz detected automatically, CAT III. Up to 63 A per phase direct (40 A with 7KT1254); above that, transformers from 1 to 5000 A primary and 1 to 5 A secondary.¹

Accuracy

Data Manager: phase current and voltage ±0.5 %, total active and reactive power ±1 % of full scale, active energy class 1, reactive energy class 2. Sensors: current ±1 % of full scale, fundamental only. Overall system 2 %.¹

Capacity

Up to eight sensor bars and 96 sensors per Data Manager, plus up to four SENTRON Powercenter 1000/1100 units.¹

Ethernet

Two RJ45 ports, 10/100 Mbit/s; DHCP needed for first commissioning. Modbus TCP server on port 502; MQTT and HTTPS REST interfaces as well.^1, 2

RS485

Two half-duplex, non-isolated connectors for the sensor bars, supplying 5 V at 280 mA; 9600 to 115200 bit/s; 8N1, 8N2 (default), 8E1 or 8O1; no more than 10 m of twisted pair.¹

Local storage

16 GB with circular buffers: 1-minute values for two days, 15-minute values for two weeks, hourly values for two months and daily values for ten years.¹

Mounting

DIN rail, 88 × 70 × 65 mm (4 modules); 300 g; IP20; protection class II; 1.5 to 25 mm² terminals for L1, L2, L3 and N.¹

Environment

-25 to +45 °C continuous, or up to +55 °C with protection no larger than 32 A; up to 75 % RH annual average; up to 2000 m; enclosed dry rooms only.¹

Interface

Documented measurements and integration boundaries for SENTRON PAC1200.

• Modbus TCP server on port 502 as standard, switched on with Enable TCP server in the Modbus settings app. The port can be changed, and port 0 switches the server off. Use Modbus TCP Server mode: in Modbus TCP Client mode the Data Manager writes its values to other servers instead.
• Register numbers are zero-based PDU addresses: Siemens calls the first two registers 0 and 1, sent as 00 00 and 00 01. The manual reads them with Read Holding Registers (FC03).
• Values that span several registers are most significant word first: the lower address holds the most significant bits and each register travels high byte first. Request every register of a value in one read; the Data Manager guarantees a consistent value only within one request.
• Total imported active power, Active power (+): registers 0 and 1, a 32-bit integer in units of 0.1 W, ({register 0} × 65536 + {register 1}) × 0.1 W.
• Total imported active energy over all phases, Active energy (+): registers 512 to 515, a 64-bit integer in units of 0.1 Wh with register 512 most significant.
• Register areas: total instantaneous readings 0 to 27, instantaneous readings per phase 40 to 147, total energy readings 512 to 551, energy readings per phase 592 to 791, configured groups 59392 to 61311 and connected sensors 61440 to 65279. The group and sensor areas exist only once groups or sensors are configured.
• The Register configuration section of the Modbus settings app selects which of those areas are served and opens the list of registers in each. The Groups app shows each group's Modbus address, the first register of its block.
• Siemens works through only the two values above in the manual. The meaning of every other register is in Siemens' Excel Modbus register table for the 7KT1261, Industry Support entry 109955592, which needs a Siemens login to download, and in the register list in the web interface.
• The web interface shows power and energy separately for import (+) and export (-). The two documented registers are the import values; take export registers from the register list rather than assuming they follow.

Setup

1. Find the Data Manager and log in

   Connect a LAN port to a network with DHCP, which first commissioning needs, open the assigned address in a browser and log in with the factory password from the rating plate. Check that the firmware version matches the manual you are using; the 01/2026 edition covers 2.1.0.

2. Check phases and sensors

   In the Sensors app, confirm that every sensor bar is detected and each sensor is assigned to the phase its circuit is on. Sensor power is calculated from that phase's voltage, so a wrong assignment gives wrong power and energy.

3. Switch on the Modbus TCP server

   In the Modbus settings app, select Modbus TCP Server, turn on Enable TCP server and keep port 502 unless the site needs another. Check that the register groups you need are selected under Register configuration, then give the Data Manager a fixed address.

4. Make one power read

   Send FC03 to register 0 for two registers and decode high word first, in units of 0.1 W, as in the worked read below. Compare the result with Active power (+) in the Data Manager app.

5. Add the points you need

   Add the energy at register 512 as four registers, then the phase, group and sensor values from the register list shown in the web interface. Keep the configuration read-only.

Common questions

Where is the full PAC1200 register list?

The equipment manual gives the register areas and works through total imported power and energy. Siemens keeps the full table for the 7KT1261 as an Excel file in its Industry Support portal, entry 109955592, which needs a Siemens login. Without one, use the Register configuration section of the Modbus settings app, which lists the registers in each area, and the Groups app, which shows each group's first register.¹

Can Edge read the sensor bars directly?

No. The sensor bars sit on the Data Manager's own RS485 bus, which also powers them, and the Data Manager turns each sensor into a virtual meter. Edge reads those values from the sensor register area, 61440 to 65279, on the Data Manager's Modbus TCP server.¹

Does the Data Manager also offer Modbus RTU?

The manual describes making the Data Manager's registers available on its RS485 connectors, with its own address from 1 to 255 and a selectable baud rate and data format (8N2 by default). Those connectors also carry the sensor bars and are limited to 10 m of cable, so this guide uses Modbus TCP.¹

How many Modbus clients can connect?

Siemens sets no explicit limit across the two RJ45 ports but says the practical number depends on how much data each client requests and how often, with at least four simultaneous connections supported. Login attempts over HTTP(S), SSH and Modbus are rate limited.¹

What happens to data when Edge stops polling?

Modbus serves current values only, so a missed poll is missing data in Edge. The Data Manager keeps its own history in circular buffers, 1-minute values for two days down to daily values for ten years, which can be viewed and exported as CSV from the web interface.¹