FB_BACnet_RemoteLoop
The following function block is used for linking a remote BACnet object of the local BACnet client. The function block for the corresponding BACnet object is linked with the aid of process data. The data exchange with the remote BACnet server takes place via BACnet with the aid of WOC (Write-On-Change) and COV (Changes-On-Value) or via polling (not recommended).
The process data can be created manually in the BACnet object, linked manually, or they can be generated automatically via PLC automapping. The comments required for PLC automapping ( (* ~ (BACnet... | ??? | ??? ) *) ) are already included in the declaration of the function block.
Use
The function block "FB_BACnet_RemoteLoop" can be used for read access to a remote BACnet object of type Loop (LOOP). To this end the remote BACnet object was added to a local BACnet client.
VAR_OUTPUT
 | Variables are only included in the extended version of the function block. The extended versions of the function blocks end with "_EX". They offer substantially more process data, although in projects with a large number of objects this may have performance implications. |
bReady : BOOL;
fControlledValue : REAL;
fPresentValue : REAL;
bOverridden : BOOL;
bOutOfService : BOOL;
bFault : BOOL;
bInAlarm : BOOL;
bError : BOOL;
nErrorId : UINT;
bReady: notification of general readiness. If this output is set, the other status outputs are valid (PresentValue, Overridden ...). If the output is FALSE, the corresponding function block "FB_BACnet_RemoteDevice" reports "not operational", the function block instances was not linked correctly in the System Manager or the remote server cannot be reached (gateway cannot be reached, no Ethernet link).
fControlledValue: feedback of the current process parameter (X, actual value).
fPresentValue: feedback of the current control output (X, control value). Attention: Present_Value and Controlled_Variable_Value can easily lead to confusion (see also BACnet specification DIN EN ISO 16484-5 for BACnet object Loop and properties Present_Value, Controlled_Variable_Value and Controlled_Variable_Reference).
fPropBand: feedback of the current control output in percent (-100%...+100%) in relation to the minimum and maximum control output (properties Minimum_Output and Maximum_Output).
bOverridden, bOutOfService, bFault, bInAlarm: see BACnet specification DIN EN ISO 16484-5 for BACnet object Loop and property Status_Flags.
bError: an error is pending.
nErrorId: error number
0 = no error
1 = function block of the associated client (RemoteDevice) is not called at all or too irregularly in the PLC program.
2 = faulty process data mapping detected (check mapping in the System Manager; if necessary compile PLC project completely and reload)
3 = the associated BACnet client is not ready (bOperational = FALSE on instance of FB_BACnet_RemoteDevice)
The error numbers can be queried as function block constants via the FB instance (FB_BACnet_Remote???.nERR_xxx).
VAR_IN_OUT
RemoteDevice : FB_BACnet_RemoteDevice;
RemoteDevice: Block instance of the corresponding remote BACnet device object. The remote BACnet device object of a remote BACnet server has been added under a local BACnet client. Local client and remote server are linked via BACnet. Any number of clients can be linked via BACnet adapter. See FB_BACnet_Adapter and FB_BACnet_RemoteDevice for further information.
Controller configuration
The controller is configured using the following BACnet properties: Action, Proportional_Constant (P-factor), Integral_Constant (I-factor), Derivative_Constant (D-factor), Bias (output offset), Maximum_Output (maximum control output) and Minimum_Output (minimum control output). See BACnet specification DIN EN ISO 16484-5 for BACnet object Loop.