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Version: 7.9


Siemens Devices

The Siemens drivers in Ignition support basic connections to S7 devices. Ignition connects to these PLCs via TCP/IP using the S7 protocol. Similar to Modbus and some Allen Bradley connections, the Siemens S7 devices do not support tag browsing. You can create S7 Tags manually in Ignition, or use Ignition's Tag import/export to create all of your Tags quickly in Excel or another spreadsheet program. Currently, Ignition has drivers for the following Siemens PLCs:

  • S7-300
  • S7-400
  • S7-1200
  • S7-1500

Considerations for 1200 and 1500 Devices

The following considerations and configurations changes must be made when using the S7-1200 and S7-1500 drivers.

  1. Only global DBs can be accessed
  2. The optimized block access must be turned off
  3. The access level must be "full" and the "connection mechanism" must allow GET/PUT
  4. Reads and Writes can not be used in TM/CT areas

Connection to a Device

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Connecting to S7 Devices

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  1. Go to the Configure section of the Gateway webpage.
  2. Scroll down under OPC-UA Server and click Devices.
  3. On the Devices page, find the blue arrow and click on Create new Device.
  4. On the Add Device Step 1: Choose Type page, select the type of device. After making a selection, click Next. There are four types to choose from:
    • Siemens S7-1500 - Which connects to Siemens S7-1500 PLCs over Ethernet.
    • Siemens S7-1200 - Which connects to Siemens S7-1200 PLCs over Ethernet.
    • Siemens S7-300 - Which connects to Siemens S7-300 PLCs over Ethernet.
    • Siemens S7-400 - Which connects to Siemens S7-400 PLCs over Ethernet.
  5. On the New Device page, leave all the default values and type in the following fields:
    • Name: S7Device
    • Hostname: type the IP address for the PLC
  6. You can check the box for Show advanced properties? to see the additional settings, but you can keep all the defaults.
  7. Click Create New Device. The Devices page is displayed showing the Siemens device is successfully created and added to Ignition. The Status will show as Disconnected and then Connected.

Unlike other PLCs, but just like Modbus, Siemens devices do not support browsing, therefore you can not browse the tags by going to the OPC Connections > Quick Client in the Configure section of the Gateway. To see and browse the tags, you need to create the tags manually as described in the Addressing section.

Configuring Siemens Addressing

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About Siemens Addressing

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The S7 protocol does not support tag browsing. Therefore, you must configure all tags in the Designer. This can be done either manually, as needed, or by importing bulk using the Tags CSV import functionality.

To manually specify each address

  1. From the Designer, in the Tag Browser, right-click on Tags folder, and then go to New Tag > OPC Tag.
  2. In the Tag Editor window, as an example, you can set the following values:
    • Name: Tag
    • Data Type: Int4
    • OPC Server: choose Ignition OPC-UA Server from the dropdown
    • OPC Item Path: [S71200]IW0, the S71200 device name goes in the square brackets then you give the address to PLC which in this example is IW0 (Word at Offset 0 in the Inputs area). The Address Syntax section below, explains how your can construct these addresses.
  3. Click OK. Now you can see the tag in the Tag Browser.

Address Syntax

You need a device name plus a tag address to create a tag. The device name is a known, but the tag address needs to be configured. Once you have both the device name and tag address you enter them in the in the OPC Item Path field of the Tag Editor window using the [device_name]address format, where device_name is the name of the device and address is the configured tag address which is described here.

Tag addresses are made up of three different components: Area, DataType, and Offset.



Data Types

Data TypeSyntaxSignedness


To form an address, you combine syntax for the desired Area and DataType with an Offset into that area. Area + Data Type + Offset

IB0Byte at Offset 0 in the Inputs area
IW0Word at Offset 0 in the Inputs area
DB500,DI8DInt at Offset 8 in DataBlock 500
ISTRING24.50A String of length 50 starting at offset 24 in the Inputs area
IX20.3Bit 3 of the Byte at Offset 20 in the Inputs area
T0Timer at offset 0 (No DataType is specified for Timers)
C0Counter at offset 0 (No DataType is specified for Counters)


It is important to note that offsets are absolute. IW0 and IW1 share a byte. To get 2 consecutive, non-overlapping words you need to address IW0 and IW2.


Bits are addressed by using the Bit DataType (X) and appending .bit to the end, where bit is in the range [0-7]. When addressing a Bit at a given offset, that offset is always treated as a Byte.


Strings are assumed to be in the S7 string format and have a max length of 210.


Timers are scaled up to a DWord and converted from S5 time format so they can represent the time in milliseconds without requiring any multipliers. When you write to a timer it is automatically converted from milliseconds into S5 time format for you. A DataType is not specified when accessing Timers.


Counters in the PLC are stored in BCD. The driver automatically converts to/from BCD for you and exposes any counter tags as UInt16 values. A DataType is not specified when accessing Counters.

Device Settings

General Settings

NameThe name of the Device Connection
DescriptionA description for the Device Connection. The description will appear on the Devices page on the Gateway.
EnabledWhether or not the connection is active. Disabling this setting terminates communication with the device.

Connectivity Settings

HostnameThe hostname or IP address of the device.
TimeoutThe request timeout, specified in milliseconds. The default is 2,000.

Advanced Settings

PortThe port to use when connecting to the device. The default is 102.
PDU SizeNumber of bytes to fit into PDU block of a single packet. Increasing this number can improve request throughput only if the processor supports a higher PDU Size. Varies from 240 and up to 960 depending on the device. The default is 240.
Rack NumberThe number of the rack that the device is positioned in. The default is 0.
CPU Slot NumberThe slot number assigned to the CPU. The default is 2.
Reconnect After Consecutive TimeoutsAfter several consecutive timeouts, the Device Connection will attempt to reconnect to the Device. This setting determines how many consecutive timeouts must occur before reconnecting.