Configuring S7-1500 Axis Control with LAxisCtrl Library

After commissioning, each S7-1500 or S7-1500T axis can be configured through one structured interface, commanded from the user program, and tested from the supplied single-axis HMI panel. The commissioning sequence below keeps the library release, technology object, configuration data, command logic, and test interface aligned.

Library and engineering-release pairing

Start with the library release that matches the project’s engineering release. The term matching here means using the published library-to-release pairing, not merely importing whichever library archive is newest. A mismatched release can introduce incompatible data types, block interfaces, or project objects before axis behavior can be tested.

1. Read the project’s engineering release.
2. Select the Motion Control library from the same row in the table.
3. Import the library and compile its types and blocks before connecting an axis.
4. Resolve import or compilation errors at this stage; changing interfaces locally makes later upgrades and comparisons harder.

Check 1: Expect the imported library objects and data types to compile without missing-type or incompatible-interface errors.

Axis technology-object connection

The library controls an axis represented by a technology object in an S7-1500 or S7-1500T project. The technology object holds the axis-specific motion configuration and runtime state; the application block supplies a standardized user-program interface to that object. Commission the technology object far enough that its assigned hardware, scaling, and motion configuration pass the engineering tool’s checks before testing library commands.

Maintain one unambiguous relationship between the application block instance and the intended axis. An incorrect reference can produce a healthy block call that observes or commands the wrong technology object. Use descriptive instance names tied to the machine axis, and verify the reference wherever the block call, configuration structure, and HMI tags are connected.

1. Create or identify the required axis technology object.
2. Complete its hardware assignment and axis configuration using the actual machine data.
3. Create the corresponding axis-control block instance.
4. Connect that instance to the intended technology object.
5. Compile the technology object and its calling program together.

Check 2: Expect the selected technology object and application block instance to reference the same physical axis, with no unresolved axis-configuration diagnostics.

Structured axis configuration

The library does not expose every command setting as a separate block input. Dynamic characteristics and position specifications are passed through a variable structure of type LAxisCtrl_typeAxisConfig. Treat that structure as the axis command configuration, not as miscellaneous storage.

1. Declare one variable of type LAxisCtrl_typeAxisConfig for the axis instance.
2. Populate its required dynamics and position-related members from validated machine settings.
3. Connect the structure to the matching axis-control block interface.
4. Monitor the structure online and confirm that no unrelated logic overwrites it.

Wrong practice is to guess individual structure members until motion starts. Read each required value from the commissioned axis data, mechanical specification, or library interface documentation.

Check 3: Expect the online LAxisCtrl_typeAxisConfig values to remain stable and to use the same units and direction convention as the technology object.

User-program integration

The axis blocks can be integrated into a user program written in LAD, FBD, or SCL. Language choice does not change the control contract: call the block cyclically, retain its instance state, present coherent configuration data, and give each command a defined owner.

Separate command selection from block execution. Operator commands, automatic-sequence commands, and commissioning commands must not write competing requests to the same instance. Apply arbitration before the block call so only one operating source controls the axis at a time. A command should transition deliberately; repeatedly reconstructing requests in several networks obscures which source initiated motion.

1. Place the axis-control block in the program path that executes cyclically while axis control is required.
2. Connect the persistent instance and its LAxisCtrl_typeAxisConfig variable.
3. Map status information to dedicated program variables for diagnostics and HMI display.
4. Combine manual and automatic requests through one selection layer.
5. Compile the complete calling hierarchy and inspect cross-references for unintended writers.

Check 4: Expect one cyclic block execution, one retained instance, and one active command source for the axis.

Single-axis HMI commissioning panel

The example project includes an HMI screen that acts as a control panel for one axis. Use it first as a commissioning interface: it provides a direct way to test the configured axis and observe command and status behavior before a higher-level machine sequence is added.

Connect the panel to the same axis instance and status data already verified in the PLC program. Keep automatic requests inactive during direct tests. Begin from a controlled non-motion condition, confirm the displayed axis identity and position, then issue only the command needed for the current check. If the panel indication changes but the PLC command does not, inspect tag mapping. If the PLC command changes but axis state does not, inspect the block status and technology-object diagnostics.

1. Open the supplied single-axis HMI screen from the example project.
2. Map its command, configuration, and status tags to the intended axis instance.
3. Confirm that displayed configuration values agree with LAxisCtrl_typeAxisConfig.
4. Test one command at a time while monitoring both the HMI and PLC online values.
5. Return every manual command to its inactive state before enabling automatic control.

Check 5: Expect each HMI action to change the corresponding PLC request for only the selected axis, with status feedback returning to the same panel.

End-to-end commissioning verification

Higher-level technology modules, including multi-belt control, can use these axis blocks as their foundation. Add such coordination only after the individual axis passes a repeatable end-to-end test. Otherwise, an axis configuration fault can be misdiagnosed as sequence or synchronization logic.

1. Check 6.1: Expect the library release to match the project release according to the pairing table.
2. Check 6.2: Expect the block instance, configuration structure, HMI tags, and technology object to identify the same axis.
3. Check 6.3: Expect the monitored dynamics and position specifications to remain unchanged unless the designated configuration source updates them.
4. Check 6.4: Expect a command from the selected control source to appear at the axis block once, without a competing request.
5. Check 6.5: Expect axis status and position feedback to propagate through the PLC variables to the HMI panel.
6. Check 6.6: Expect the command to complete or produce a diagnostic that can be traced through the block status and technology-object diagnostics.

Frequently asked questions