Connections table

The table in which you define the connections that Live uses to communicate with the PLC and other devices: driver, address, port, timeout and driver-specific parameters.

What is a connection

A connection is the single-row definition of the information needed to exchange data with a device (PLC, OPC server, MQTT server, Modbus device). Tags are read from the PLC and written to the PLC by being bound to a connection; a tag without a connection becomes an internal tag and its value lives only inside Live. Connections are defined in the Connections section of the project tree.

Live runs a separate read cycle for each active connection. A device that does not respond does not delay the other connections. Studio does not connect to any device: the live state of a connection is visible only in Live (Connection diagnostics).

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1. Add — new connection row.
2. Name — unique; the dot next to it is the color of the connection.
3. Communication driver — determines the protocol.
4. IP address / computer name — the network address of the device (the COM port for serial drivers).
5. Port — the default port of the driver is filled in.
6. Timeout (ms) — how long to wait for a response from the device.
7. Enabled — if off, Live does not establish the connection.

Adding a connection

1. Open the section

   In the project tree, click the Connections section.

2. Add a row

   Click the Add button on the toolbar or the Add new row row below the table. The new connection is created with these values: name Baglanti_1 (the number increases for later connections), driver Siemens S7-1500, address the first unused address in the 192.168.0.x range, port 102, timeout 2000 ms, Enabled on, the first unused color from the color palette.

3. Change the name

   The name must begin with a letter; it can contain only letters, digits and _ and must be unique in the project. The name appears in the Connection column of the tag table.

4. Select the driver

   Select the driver that suits your device from the Communication driver cell (Drivers). When the driver changes, the port and driver parameters return to that driver's defaults (the arbiter address is kept). For drivers that do not need a network address, the address is cleared; for serial drivers (Modbus RTU / ASCII), the address becomes COM1 if it is not a valid COM port.

5. Type the address

   In the IP address / computer name cell, enter the IPv4 address of the device (192.168.0.10) or the computer name (PLC-HAT1); for a Modbus RTU / ASCII connection, enter the serial port (COM3). An invalid address is not accepted into the table; the reason is shown below the cell. If you paste the address in the form opc.tcp://192.168.0.5:4840/yol or mqtts://sunucu:8883, only the server part goes into the address; the port and (for OPC UA) the endpoint path are written to the corresponding fields, and mqtts:// sets the security to TLS.

6. Enter the parameters

   With the row selected, the <Driver name> parameters card opens on the Properties tab of the Inspector window: driver-specific fields such as rack / slot, unit ID, security, serial port settings and backup PLC are entered here. Below it there is also the Arbiter (redundant server) card (see below).

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   1. Driver — when it changes, the port and parameters return to the default.
   2. Rack — 0 – 7.
   3. Slot — the slot in which the CPU is installed.
   4. Target — the address the connection goes to and the data types it can carry.

7. Test

   Use Online›Test connections… to see whether the device can be reached (details), and check the project with F7.

Columns

The Connections section can be grouped: a Group filter appears in the table and folders appear in the project tree (Table editor).

Address rules

The network address is validated with the following rules:

• If it contains only digits and dots, it must be IPv4: four parts, each 0 – 255, with no unnecessary leading zero (192.168.01.5 is invalid), the first part in the range 1 – 223.
• If it contains other characters, it is treated as a computer name: letters, digits, - and . can be used; the name must start and end with a letter or a digit.
• For the serial drivers, the address is COM followed by a number from 1 to 256; lowercase letters and spaces are corrected (com 3 → COM3). Any other format is rejected with the message "COM-A" bir seri port adı değil. Seri port COM1 – COM256 biçiminde yazılır (ör. COM3).
• An empty address is not accepted (except for OPC DA).

This check is not done for OPC DA and MQTT connections: one computer can host several OPC servers, and one MQTT server can have several connections. Modbus RTU / ASCII connections also share the same COM port (devices on one RS-485 line); the serial port settings of these connections must be identical (Modbus serial line). Studio still suggests an unused address for a new or duplicated connection; if you want to use the same IP, type the address yourself. If connections whose driver, port or parameter is changed later end up on the same device endpoint, the problem appears as an error in the Check project list.

Target card

The Target card in the Inspector shows where the binding goes and which data types it can carry:

Arbiter card

At the bottom of the Inspector of every connection except Simulator there is the Arbiter (redundant server) card. Its only field is Arbiter address (Int): in a redundant server pair, the master writes a counter that increases every second to this address; if the network between the two computers fails, the standby sees that the counter is increasing and does not take over the master role. Empty = this PLC is not an arbiter. When and how to use it: PLC arbiter.

• While the address is empty, examples suitable for the driver are shown on the card; when it is filled in, Valid arbiter address: … or the reason for the error is shown.
• The address must follow the driver's Int rule and be in a writable area; input / output and read-only areas are rejected.
• An address that is the same as that of a tag on the same connection gives a warning. While the operating mode is Single station, the address is not used; a note appears in Problems.

Connection status tag

When each connection is created, an internal Bool tag named <Bağlantı adı>_Baglanti is added automatically (1 = connected). Live writes its value; it can be used in animations, alarms and scripts. If the connection is renamed, the tag name follows (unless you changed it manually); if the connection is deleted, the tag is deleted too. Details: Connection diagnostics.

Duplicating, deleting, Excel

• Duplicate (Ctrl+D): the copy receives a new name, a new color from the palette and (for drivers that need a network address) the first unused 192.168.0.x address. The copied connection gets its own status tag.
• Delete (Delete): tags bound to the connection are not deleted; tags that refer to the connection records produce the error refers to a deleted record in the Check project list. Move these tags to another connection.
• Excel: the table can be exported to Excel and imported again. Driver parameters (rack / slot, unit ID, PLC series, serial port settings, backup PLC, arbiter address, etc.) are not written to Excel; a connection added from Excel starts with the driver’s default parameters, and a connection whose driver is changed in Excel reverts to the default port and parameters.

Limitations and points to note

• After changing the connection settings, save the project and upload it to Live (Uploading to Live); Live establishes the connections when the project is opened.
• For drivers that require authentication (OPC UA, OPC DA, MQTT), the user name is entered in the project and the password on the Live computer: Connection security.
• The connection addresses in the Demo Project are examples; enter the address of your own device.