1.8.8. Diagnostic Information

The diagnostic information consists of two different parts:

1. Bit-Field in every connector for the general diagnostic information

1. Extended diagnostic information of a device with detailed information

The Bit-Field can be used e.g. for the online-diagnostic information in the device tree to see, if one device has an error or has some information for the user.

The extended diagnostic information can be used to display some device specific information about an error or a special detected state.

These parameters are explained now in detail.

1.8.8.1. General diagnostic information bit-field

The actual state of a device can be published in a bit-field, that is a generic part of each connector. This is a bit-field (32-Bit) with the following meaning:

Bitname	Bit-Value	Is set by	Description
CF_ENABLE	0x0001	IO-Config	Connector enabled in the IO-configuration
CF_DRIVER_AVAILABLE	0x0010	CmpIoMgr	A driver has registered to this device, so the device will be supported by a driver.
CF_CONNECTOR_FOUND	0x0020	IoDriver	Connector found (device detected)
CF_CONNECTOR_CONFIGURED	0x0040	IoDriver	Connector configured
CF_CONNECTOR_ACTIVE	0x0080	IoDriver	Connector active (bus is active)
CF_CONNECTOR_BUS_ERROR	0x0100	IoDriver	Bus error
CF_CONNECTOR_ERROR	0x0200	IoDriver	General error
CF_CONNECTOR_DIAGNOSTIC_AVAILABLE	0x0400	IoDriver	Extended diagnostic information available

The Connector flags must always be set out of the IO-diver with the functions IoMgrConfigSetDiagnosis() and IoMgrConfigResetDiagnosis() of the IO-manager to set and reset single diagnostic bits.

If CF_CONNECTOR_DIAGNOSTIC_AVAILABLE is set, two diagnostic parameters out of the device description are used to transmit further extended information.

This bitfields is monitored by CODESYS, if the target is online.

If everything is OK (the bits CF_ENABLE, CF_DRIVER_AVAILABLE, CF_CONNECTOR_FOUND, CF_CONNECTOR_CONFIGURED, CF_CONNECTOR_ACTIVE are set), the following Icon is displayed at the corresponding device (connector):

If something is wrong (one of the bits CF_CONNECTOR_BUS_ERROR, CF_CONNECTOR_ERROR or CF_CONNECTOR_DIAGNOSTIC_AVAILABLE is set or one of the other bits is not set), the following Icon is displayed at the corresponding device (connector):

After a new initialization of the fieldbus (new download, reset of application) the state of a fieldbus (CF_CONNECTOR_ACTIVE flag is set or not) depends on whether the fieldbus is already running or not. This means that it depends on the fieldbus, if the connector has got a green (fieldbus already running) or an red (fieldbus not running) icon after a new initialization.

The table shows the icons of some field busses after a new initialization:

1.8.8.2. Extended diagnostic parameter

The parameter with the attribute “diag” can be a structure, string or whatever. This contains the extended diagnostic information of this device, if the corresponding device dialog with the register card “Status” is opened in CODESYS. In this situation, a IoDrvReadParameter() /IoDrvReadParameterById() is called of the corresponding driver of the device.

The parameter can be specified in the device description as followed:

<Parameter ParameterId="327936" type="local:TslaveDiag">
 <Attributes channel="diag" download="true" functional="false" offlineaccess="read" onlineaccess="read" />
   <Default>
       <Element name="Status1">0</Element>
       <Element name="Status2">0</Element>
       <Element name="Status3">0</Element>
       <Element name="MasterAddress">0</Element>
       <Element name="IdentNumberHigh">0</Element>
       <Element name="IdentNumberLow">0</Element>
       <Element name="ExtDiag en">58</Element>
       <Element name="ExtDiag">[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]</Element>
   </Default>
   <Name name="local:Id327936">SlaveDiag</Name>
       <Description name="local:Id327936.Desc">ProfiBus DP slave diagnostic information</Description>
</Parameter>

1.8.8.3. Extended diagnostic acknowledge parameter

To acknowledge the extended diagnostic information, there is a second parameter with the attribute “diagAck”. This is always a bool parameter to reset the CF_CONNECTOR_DIAGNOSTIC _AVAILABLE bit. This is executed by pressing the Diag Acknowledge button in the device dialog. In this situation, a IoDrvWriteParameter() /IoDrvWriteParameterById() is called of the corresponding driver of the device.

After pressing this button, the diag flag CF_CONNECTOR_DIAGNOSTIC_AVAILABLE must be reset by the IO-driver. After this, the parameter with the “diag” attribute is never read by CODESYS, until CF_CONNECTOR_DIAGNOSTIC_AVAILABLE is set the next time.

<Parameter Parameter"d="327937" type="std:BOOL">
  <Attributes channel="diagack" download="true" functional="false" offlineaccess="read" onlineaccess="readwrite" />
  <Default>0</Default>
  <Name name="local:Id327937">SlaveDiagAcknowledge</Name>
  <Description name="local:Id327937.Desc">ProfiBus DP slave diagnostic acknowledge</Description>
</Parameter>

1.8.8.4. Implementation notes

To realize an identical behavior of all IO-drivers regarding the IO-diagnostic information, some implementation details and requirement must be known:

Requirement
R01	The diagnostic bits in the Bit-Field must be written cyclically from the IO-driver itself! For this, the standard IO-driver interface function IoDrvGetModuleDiagnosis() contains the cyclic diagnostic transfer. This function is not called automatically from the runtime kernel. Typically, this function is called implicit in the IO-driver in IoDrvStartBusCycle.
R02	IoDrvGetModuleDiagnosis() must only set the diagnostic bits cyclically and must not read any time consuming specific diagnostic information of a slave! So the runtime of this function must be as short as possible, because this has an effect on the cycle time of an IEC-task! If the time is too long to set the information in one cycle, only diagnostic information of a few slaves should be read per cycle!
R03	If a slave is disabled in the IO-configuration, no diagnostic information may be set (CF_ENABLE is disabled in this case)
R04	If a slave is configured but not available physically (e.g. bus is disconnected), the diagnostic information must be updated always!
R05	Unimportant extended diagnostic information should be acknowledged and handled by the IO-driver implicitly. This depends on the type of fieldbus: Profibus DP: For example, if a slave informs about the activation of the watchdog is a information, that can be implicitly acknowledged.
R06	The relevant extended diagnostic information must be available, until this parameter is acknowledged by the user (or the program!) with the extended diagnostic acknowledge parameter!