Symbolic Access to I/O Channels

You get direct access to the I/O channels of your device by means of specially generated function blocks, without having to actively set up a mapping manually for each device and for each channel.

. Automated generation

The inputs and outputs are combined into a function block under the name of the I/O channel. If possible, the basic block defined in the device description is extended.
The channel name corresponds to the name as specified in the device editor on the I/O Mapping tab in the "Channel" column.
The input and output variables created in this way are also displayed in the Input Assistant.
If the I/O channels are structured or enumerations, then their function blocks are also structured accordingly. As such, the generated function blocks contain structured inputs and outputs or enumerations.
For channels with identical names, the suffix _<X> is appended to the input or output of the function block.
If a device does not have its own I/O channels (example: EK1100 Slave), then no function block is created.

Enable automatic mapping

In the Devices view, open the top device. In the device editor, select the PLC Settings tab.
Under Additional Settings, there is the Enable symbolic access for I/Os option.
Select the check box.
The generated function block instance is displayed on the IEC Objects tab of the device.
For each I/O channel, a (usually extended) function block is now automatically created and instantiated. This provides you with direct access immediately. You can access the I/O channel by means of the variables of the function block.

Example 483. Example: EtherCAT Slave

The new function block extends the existing function block. The EL1008 function block instance is listed in the device editor below the EtherCAT IEC Objects tab.

The DrvEthercatLib.ETCSlave_Diag function block is extended to EL1008_FB and gets the output variables Input_<n>.

Figure 3. Function block: EL1008_FB

Example 484. Example: Device without a defined basic block

If no function block is defined in the device description which can be extended, then a new function block is generated. For example, the Generic_XN1AI function block instance is listed in the device editor below the IEC Objects tab.

Figure 4. New function block: Generic_XN_1AI_F

Example 485. Example: CANopen

The BK5120_FB function block, which extends the existing _3SCOS.CANRemoteDevice function block according to the device description, is generated. The BK5120 function block instance is listed in the device editor on the CANopen IEC Objects tab.

Figure 5. Function block: BK5120_FB

Online Mode

In online mode, the data is updated by means of the existing functions. However, only those of the generated variables which are actually used are updated. Or if the Always update variables option is enabled.

If a channel is simultaneously accessed symbolically and via I/O mapping, then compiler warnings are issued.