One or more devices can be connected to the HMI/SCADA system via one defined Port. Device table will define the setting/behaviour of the connected device(s). A device can be a PLC, a RTU unit, a transmitter that possess communication capability., or even a software application that exposes data.
Devices are inherited from Ports, so it must be created under a desired Port.
- Name
-
Any unique name for the configured device.
- Description
-
Additional description.
- Address
-
Numerical type node address, or device ID. For example Modbus node.
- Path
-
String type node address, or device ID. For example, OPC Server name: 'RSLinx OPC Server'.
- Driver
-
Choose the protocol to communicate with this device.
![[Note]](images/note.png)
Note
Some protocols have additional attributes to set. Please refer to Device Driver for more details.
- Timer
-
Choose device polling rate.
- Max Connection
-
This setting is applicable only to ethernet base device. Ethernet base device could possibly support more than 1 connection for faster speed. By default only 1 connection will be established for each device.
Enter -1 to let I/O manager automatically handle connection pool.
Enter 0 for unlimited connection. I/O manager will create as many connection as possible to enable fastest communication with the device. However, this may not be the best case, because some devices do not support too many concurrent connection. Some devices even does not support concurrent connection. Please refer to your device documentation to understand the limitation of the device.
Enter any positive integer for other number of concurrent connection.
Note
Serial and parallel communications shall always default to 1 connection.
Very often engineer needs to provide a page of network layout to display its connection status. Each device status can be obtained via system tags based on the name given by engineer. For instance, if a device is named as "PLC01", then a list of status tags will be available for relevant usage. The name of tags can also be obtained from Tag window in Server Interface. Engineer could click the dropdown list to check the available tags promptly.
Please refer to Application Tag and look for all application tags start with app.device[XX] for runtime tags created for each devices.
![[Tip]](images/tip.png)
Tip
More than one device setting can be configured for a single physical device. For instance, one device may have different byte ordering for Float data as compare to Long Integer, then two device settings are needed.