Innovation in Motion

Advanced Topics:

Multiple SHAs in a project. When multiple SHAs will be controlled in a project, create a unique SHA_PositionControl instance for each. For SHAs that are identical (and/or will be synchronized), it is possible to use the same SHA_Config for them; otherwise create unique SHA_Config tags for each one.

Coordinated or synchronized SHAs. If two (or more) SHAs will be used which need to move together, then a typical solution is to setup virtual position axes for each SHA, and then when they are properly aligned, issue MAG instruction(s) to Gear each slave virtual position axis to the master virtual position axis.

CAM profiles. If there are defined position and force profiles that are needed, then a CAM profile could be created for the application.

Load Cells. When a LoadCell is used for Force feedback, then its properly scaled feedback tag will be used as the AOI Extend Pressure (for an extend load), or as the AOI Retract Pressure (for a retract load cell). Then the SHA_Config.ExtendForceGain and SHA_ConfigRetractForceGain MUST be set to 1, instead of using any factor provided values. If the Load Cell and SHA will be used only for Extend, then the RetractPressure input can be set with a value of 0, and the SHA_Config.RetractForceGain can be set to 0. Conversely, if the load cell and SHA will only be used for a Retract Force limit, then set the ExtendPressure to 0 and set the SHA_Config.ExtendForceGain to 0.

If the Load Cell will be used for both Extend and Retract Force limits, then if the Load Cell returns positive values for Extend (compression) and negative values for Retract, then use that signed, scaled value into the Extend Pressure input and set the Retract Pressure input to 0. Or, alternately, when the Load Cell is compressing, send its positive value to the ExtendPressure input, and set the RetractPressure tag’s value to 0. Then, in the Retract case, set the ExtendPressure input tag to 0, and post the absolute value of the negative load cell feedback value to the RetractPressure input.

The AOI Force output in Extend force cases will show a positive Force, and in the Retract force case, the Force output will be a negative value.

In general terms, the Force output of the AOI will be the net force, calculated as: (Extend Pressure * SHA_Config.ExtendForceGain) – (Retract Pressure * SHA_Config.RetractForceGain).