Danfoss MCO 305 Design Manual

Also see for MCO 305: Operating instructions Operating instructions Design guide

MCO 305 Design Guide__ APOSS Tools __MG.33.L5.02 – VLT® is a registered Danfoss trademark 117 Oscilloscope VersionsThere are four versions of the Oscilloscope available to users. Each version is designed for a different usebut all versions basically operate in a similar manner and have a similar appearance. The Free Run, SingleShot, and TESTSETP Oscilloscopes are designed for debugging and diagnostics. The Tune Oscilloscope isdesigned for optimizing system performance.Free Run OscilloscopeThe Free Run Oscilloscope is a tool designed specifically for diagnosing operational problems in runningsystems. However, it can also be used for debugging prototype applications. It is referred to as “Free Run”because the application on the controller can run freely without regard to how the Oscilloscope is being usedor that it is being used at all. The impact of the existence and usage of the Oscilloscope on the runningapplication has been minimized as much as possible. This allows the controller to behave as it would inactual operational situations.Values are recorded and displayed in real time during the actual test. This information is normally collectedusing PDO messages from the controller.NB!:Note that PDO messages are not supported by some older controllers and by some connectioninterface types.Free Run Oscilloscope in Polling ModeIn certain circumstances, the user may be unable or unwilling to allow the Oscilloscope to use PDOmessages. Reasons for this include the following:− The running application may already be using all available PDO message types. In this case, there willbe no free PDO message type that the Oscilloscope can use to receive curve data from the controller.− The controller may have an older version of firmware installed that does not support the dynamicconfiguration of PDO messages. The Oscilloscope will then be unable to configure the required PDOmessages.− The controller may be connected using a connection interface type that does not support PDOmessages.In these cases, the Free Run Oscilloscope either cannot be used or must be used in the slower “polling”mode. Note that using polling can have a significant impact on the performance and response of thecontroller and the communication network.If the Free Run Oscilloscope cannot be used, then it may be possible to use the Single Shot Oscilloscope asan alternative.Single Shot OscilloscopeThe Single Shot Oscilloscope is designed more for debugging prototype applications than it is for diagnosingoperational problems in running systems. However, it can be used for both. It can also be used in somesituations where the Free Run Oscilloscope cannot be used.It is referred to as “Single Shot” because the curve data is recorded on the controller itself and thenuploaded to the Oscilloscope after the test is complete.Values are recorded on the controller in a TESTSETP array. The allocation of this array can be done eithermanually by the user (i.e. by defining a user array for the purpose) or automatically using available freememory in the controller. In either case, the Single Shot Oscilloscope may affect the memory managementof the application program. The TESTSETP array will be automatically configured by the Single ShotOscilloscope when recording begins.NB!:Some older controllers do not support the automatic configuration of TESTSETP arrays. In these cases,the Single Shot Oscilloscope cannot be used; the TESTSETP Oscilloscope should be used instead.