Use the Siemens LOGO! Connector to read and write values in a Siemens LOGO! 0BA7 or 0BA8 controller over Ethernet.

This guide explains how to prepare the controller connection, configure an instance, create items for LOGO! memory areas, and troubleshoot communication.

Prerequisites

Before you begin, make sure that:

• The Siemens LOGO! Connector is installed.
• SIA Connect can reach the LOGO! controller by IP address or hostname.
• The LOGO! project contains an Ethernet connection that permits communication with the external partner.
• You know the local and remote TSAP values configured for the connection.
• You know whether the controller is a 0BA7 or 0BA8 model.
• You know the memory addresses and data types that you want to read or write.

Understand the TSAP settings

The TSAP values identify the two endpoints of the configured connection. Enter the values from the Ethernet connection in the LOGO! project.

For example, if the controller uses local TSAP 20.00 and its configured partner uses TSAP 30.00, enter 30.00 as Local TSAP and 20.00 as Remote TSAP.

Create a Siemens LOGO! instance

1. In the Edge Portal, go to Instances.
2. Select Create instance.
3. Select the Siemens LOGO! Connector.
4. Enter a name for the instance.
5. Enter the IP address or hostname of the LOGO! controller in Address.
6. Enter the TSAP assigned to SIA Connect in Local TSAP.
7. Enter the controller TSAP in Remote TSAP.
8. Select the controller generation in Device type.
9. Select Create.

Instance parameters

When the instance is created, the Connector also creates read-only identity items for Vendor, Model, Serial, Firmware, and Product code. Values are shown when the controller provides the corresponding information.

Create an item

The Siemens LOGO! Connector does not discover process items. Create each item manually.

1. Open the Siemens LOGO! instance.
2. Open the Items tab.
3. Select Create item.
4. Enter a unique item name.
5. Select the required Memory area.
6. Enter the Offset.
7. Select the Type when using V memory.
8. Configure the remaining item settings as required.
9. Select Create.

Item parameters

Memory areas

Address V memory

For V memory, enter the byte address shown in the LOGO! project. Do not convert the address to a one-based item number.

Supported data types

Configure strings and arrays

Strings

A Siemens STRING uses two header bytes before its character data. Specify the complete byte range in the Offset field.

• 20-12 starts at byte 20 and reads 12 bytes in total. This allows 10 character bytes after the two header bytes.
• 20-31 reads bytes 20 through 31 inclusive. This is also a total of 12 bytes.

Numeric arrays

Add an ending byte offset after a hyphen to read an array. For example, a REAL array that starts at V100 and ends at V111 uses offset 100-111 and contains three 4-byte values.

String arrays

Use parentheses to define the size of each string element. For example, 0(27)-54 reads three strings that each occupy 27 bytes, starting at byte offsets 0, 27, and 54.

Array values are returned and written as compact JSON arrays, such as [10,20,30].

Verify the connection

1. Open the instance and confirm that it is running without a connection error.
2. Open the Items tab.
3. Confirm that the required items receive current values.
4. If writing is required, write a safe test value to an item that is intended to be writable.
5. Confirm the result in the LOGO! project or connected equipment.

Troubleshoot the Siemens LOGO! Connector

The instance reports Unreachable peer or Connection timed out

• Confirm that the controller is powered and connected to the network.
• Confirm that the instance uses the correct IP address or hostname.
• Use the Ping tool to test network communication from SIA Connect.
• Confirm that TCP port 102 is permitted by switches, routers, and firewalls.

The instance reports an ISO connection error

• Confirm that the Ethernet connection is configured in the LOGO! project.
• Confirm that Local TSAP contains the TSAP assigned to SIA Connect.
• Confirm that Remote TSAP contains the controller's local TSAP.
• Confirm that the configured partner connection is permitted by the controller.

The instance connects but item values are incorrect

• Confirm that Device type matches the controller generation.
• Confirm that the correct memory area is selected.
• For V memory, use the direct byte address. For example, V100 uses offset 100.
• For digital or analog I/O, use the one-based input or output number.
• Confirm that the selected V-memory data type matches the value in the LOGO! project.

The item reports Invalid offset in address

Check the offset syntax. Remove unsupported characters and confirm that ranges, bit numbers, and string lengths are complete.

The item reports Address out of range or Item not available

• Confirm that the address exists on the selected controller model.
• Confirm that the offset is within the supported range for the selected memory area.
• Use network memory areas only with a 0BA8 controller.
• Confirm that the complete multi-byte value fits in the available memory range.

A string reports Could not determine length of string

Enter a valid STRING range that includes the two header bytes and the character data, such as 20-12.

An array write reports Invalid format

Write the value as a valid JSON array with the correct number of elements, such as [10,20,30]. Make sure every value is valid for the configured data type.

A TIME item does not return a usable value

The current Connector exposes TIME in the item form but does not implement its read or write conversion. Use another supported representation in the LOGO! project when possible.

Identity items are empty

The controller may not have returned the corresponding CPU information. Confirm that the instance is connected. Empty identity values do not by themselves indicate that process-item communication has failed.

Related articles

• Install and manage Connectors
• Create and edit instances
• Create and edit items
• Use the Ping tool
• Siemens LOGO! releases
• Configure the Siemens S7 Connector