Technology

Siemens S7 PLC data collection: S7-1200, S7-1500, S7-300 and S7-400

We read production data from your Siemens PLCs without changing the PLC program and deliver it to MES, OEE, ERP and reporting systems.

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Our clients

Siemens
Anadolu Isuzu
BSH
Tofaş
Toyotetsu
Martur
Turkcell
Vodafone
Doğadan
Pakmaya
Bross
Abdi İbrahim
Nobel İlaç
Plastimak
Dalgıç Kalıp
Barbaros Motor
Magneti Marelli
Rözmaş
Sanel

Siemens S7 PLC data collection means reading a machine's counters, states and process values over the network without touching the PLC's control logic. The S7-1200 and S7-1500 are the families we meet most often; older lines still run S7-300, S7-400, S7-200 and S7-200 Smart CPUs.

VOLSOFT is a software and integration engineering firm, not an automation contractor: we do not program PLCs. We build the data layer above them. Together with the plant's automation team we agree which values are read, from which data block and address, and how often, then commission the reading on Proxus.

On the S7-1200 and S7-1500 there are two routes. S7comm (ISO-on-TCP, port 102) reads directly, but needs PUT/GET access allowed in the CPU and optimized block access turned off on the data blocks being read. The alternative is the CPU's OPC UA server, enabled in TIA Portal: optimized blocks stay as they are, and the automation side decides which variables the server exposes.

What we deliver

Siemens S7 PLC data collection

Direct S7comm reading

We connect to S7-200, S7-200 Smart, S7-300, S7-400, S7-1200 and S7-1500 CPUs on port 102. Rack and slot are set per CPU family, and the connection test also reads the CPU's order number.
TIA Portal OPC UA server

When the OPC UA server is enabled on an S7-1200 or S7-1500, we read through the OPC UA driver instead. It is our preferred route when turning off optimized block access is not acceptable.
PUT/GET and optimized blocks

The PUT/GET permission and non-optimized data blocks that S7comm needs are changes to the PLC project. We do not make them: we specify them in writing and plan them with the plant's automation team or PLC integrator.
Data types and tag lists

We read Siemens data types such as BOOL, INT, DINT, REAL, WORD and STRING with the right length and byte order. Every value is listed with its data block number and offset in one tag list.
Read-only, segmented network

By default we only read. If a write is needed, the address and who approves it are defined separately. The edge server sits in the OT network and connects out to the central server, so no inbound port is opened into OT.

How a project runs

From discovery to live, step by step

01
PLC inventory

We list CPU models, firmware versions and IP addresses on the line, and who holds the current TIA Portal or STEP 7 projects.
02
Choose the route

For each PLC we choose S7comm or OPC UA with the automation team and send the required PLC settings in writing.
03
Tag list

Counters, states, alarms and process values are listed with data block address, data type and read interval, and placed in the shared data model.
04
Commission and verify

We start reading on a Proxus edge gateway and check the values against the HMI or SCADA before anything downstream uses them.

Built on Proxus

Proxus's Siemens driver does the reading. It runs on the edge gateway in the plant network, with no separate OPC server in between. Values flow into the Unified Namespace and on to MES, OEE, ERP and databases.

Proxus is the industrial data platform built by the VOLSOFT team.

Proxus Siemens S7 driver ↗

Frequently asked questions

Common questions

How do you collect data from a Siemens PLC?

Over Ethernet, either with the S7comm protocol or through the OPC UA server on S7-1200 and S7-1500 CPUs. S7comm needs PUT/GET access and non-optimized data blocks; OPC UA needs the server enabled in TIA Portal and the variables published.

Should we use OPC UA or S7comm on an S7-1500?

If optimized block access must stay on, OPC UA is the cleaner route. If the firmware or licensing does not allow OPC UA, or the PLC project can be changed, direct S7comm works well. We decide per PLC from the inventory.

Do you change the PLC program to collect data?

No. We do not touch the PLC program or its control logic. Settings such as PUT/GET access live in the PLC project; we specify them and plan them with the plant's automation team.

How are Siemens S7 data types handled?

Each tag is defined by data block number, offset and data type. BOOL, INT, DINT, REAL and STRING values are read with the PLC's length and byte order, so they match what the HMI shows.

Can you read older S7-300 and S7-200 PLCs?

Yes. S7-300, S7-400, S7-200 and S7-200 Smart CPUs with an Ethernet connection are read with the same driver. Which CPU uses which route is settled during the site survey.