This post is the final entry in DMC’s Getting Started with TwinSAFE series, designed to help you build confidence in configuring and commissioning TwinSAFE safety systems. If you’re new to the series, be sure to review our earlier guides in this series.
Getting Started with TwinSAFE Series
In this post, we’ll introduce the Safe Motion Wizard—a powerful tool for quickly generating safety projects for your drives—and walk through best practices for post-wizard configuration.
One of the many useful features included in Beckhoff’s TwinCAT XAE Shell is the Safe Motion Wizard. When configuring the safety project for your drives, the Safe Motion Wizard will help configure your Safety Project for STO (Safe Torque Off), SS1 (Safe Stop 1), SDlp/n (Safe Direction positive and negative), and more.
Not all features are available for all drives, so make sure to consult the Beckhoff website for supported features when selecting which drives to use for your project. If you need help making these selections, help evaluating the safety risks of your designs, or automation help in general, please contact our experienced automation and safety teams.
Using the Safe Motion Wizard
To make use of the Safe Motion Wizard, you will need to have a device configured in a Drive Manager Project in your solution. The Safe Motion Wizard will reference this device to determine how to configure the resulting safety project.
The safety motion wizard can be found under the TwinSAFE tab in the toolbar. Navigate to “TwinSAFE>Wizards>Start Safe Motion Wizard…”:
The first window displayed, “Select Project Targets”, will allow you to select which devices you would like to configure Safety Projects for via the Safe Motion Wizard. Begin by selecting the Target Type at the top of the window. This should match the hardware you have or plan to use.
If you do not see your hardware as an option in the window, you may need to update the installed version of TE9000. As the Safe Motion Wizard is a more recent feature, it is still being updated as new hardware is released or support is added for existing hardware. The latest version of this post is TE9000 version 1.4.8.
Once you have the target type selected, select the corresponding device that has been configured in the Drive Manager Project, then select “Next”:
The second window, “Select Safety Feedback”, will have you select the encoder feedback per drive. Select this to match the physical device setup:
The third window, “Select Safety Function”, will allow you to choose which safety functions you would like to use for the project. When selecting safety functions, make sure the hardware you have supports the features you select. Information about supported features can be found on the Beckhoff website:
The fourth window, “Configure TwinSAFE Projects”, lets you choose a project name for each project that will be generated. After choosing a name for each project, proceed to the next page.
The fifth page, “Assignment of Master Target Logics”, allows you to assign the logic to an existing project. If you leave the selection empty, a new project will be created per target:
The sixth window, “Safe Address Selection”, will let you enter the safe address for the target. This can be changed later if the safe address changes, or you do not know the safe address at the time of the project’s creation:
The final window, “Finalization”, is simply a warning to notify you that this is an automatically generated project template and should be reviewed thoroughly before use.
Post-Wizard Configuration
The project generated by the Safe Motion Wizard is not intended to be a standalone solution as it does not inherently have logic to determine when to set the various configured signals (SS1, STO, etc). By default, the command signals are intended to be received from another Safety Project via an FSoE Connection:
The “Connection Input” and “Connection Output” TwinSAFE Groups created by the wizard expose command and status signals based on the safety functions you selected. If you are using a separate safety controller, then you will use the FSoE Connection to pass signals; however, if this is your main safety project, then you will need to remove these two groups and write to the related variables directly.
Working within a Single Safety Project
The easiest way to set the STO and SS1 logic within the generated project is to remove the FSoE Connection and interface with the “ChX.sgvl” global variable lists directly. If you delete the safeDecouple blocks from the input and output safety logic blocks, then you can write directly to the values per channel in the safety global variable list. This “ChX.sgvl" file is where the logic in the main TwinSAFE groups will grab input/output variables from.
The following are the blocks that decouple data for the FSoE connection and route it to the “ChX” global variable list:
The following is an example of a block directly writing to the “ChA.sgvl” safety global variable list.
Channel-Specific Error Acknowledgement
In addition to the safety response commands such as STO or SS1, your safety logic will have to handle an additional “Error_Ack” handshake meant specifically for the drives. Similar to how the Group Port “Err Ack” requires a rising edge signal to clear errors in a TwinSAFE Group, the “Error_Ack” available for each channel will be required before the safety responses associated with that channel can be released.
The ”Error_AckReq” status for each channel is the indicator to let you know when the “Error_Ack” response is required.
An example of operational behavior goes as follows:
- STO_ChA is true and STO_active_ChA is true
- Safety designates that STO_ChA should drop false
- STO_active_ChA drops false in response to the command
- The cause of STO loss is and STO_ChA returns to true, STO_active_ChA remains false while Error_AckReq_ChA is true
- Error_Ack_ChA is pulsed, clearing the drive error and allowing STO_active_ChA to rise to true
Conclusion
From this point, you should possess the knowledge required to set up a project via the Safe Motion Wizard.
If you aren’t properly equipped to develop your own safety solution or would like help from safety-certified experts, please feel free to contact us for help developing your safety solution.
Special thanks to Dominic Del’Olio and Hannah Gjovik for their contributions to this blog’s content.