FB_ReadAdsSymByName

The block enables the reading of any value from another controller with the aid of the symbol name.

On a rising edge at the bRead input the block reads the value of the variable sVarName from the selected ADS device (e.g. PLC). The ADS device is indicated by the AMS-NetId (sNetId) and the AMS Port number (nPort). The value is written into the variable to which nDestAddr points.

The internal mode of operation of the block can be changed with the aid of the eComMode input:

eComMode := eAdsComModeSecureCom: Following each read procedure the handle of the PLC variable is released again. This mode should be used when values are exchanged very slowly.

eComMode := eAdsComModeFastCom: As long as the sVarName, sNetID and nPort inputs do not change, the handle of the PLC variable will not be released after each read procedure. This mode should be used when values are exchanged very frequently.

bRead        : BOOL;
sNetId       : T_AmsNetId;
nPort        : T_AmsPort := AMSPORT_R0_PLC_RTS1;
sVarName     : STRING;
nDestAddr    : DWORD;
nLen         : UDINT;
tTimeout     : TIME := DEFAULT_ADS_TIMEOUT;
eComMode     : E_AdsComMode := eAdsComModeSecureCom;

bBusy        : BOOL;
bError       : BOOL;
nErrorId     : UDINT;