FB_WriteDWordOnDelta
The function block enables event-driven writing of a variable of type DWORD.
The FB_WriteDWordOnDelta function block checks cyclically whether the value at the nSignal input has changed. The cycle time for checking is determined by the parameter tCycleTime. If 0 s is given for tCycleTime, the input signal is examined during every PLC cycle. If the comparison establishes that the current value is greater than the value nUpperLimit or lower than the value nLowerLimit, then the value of the signal is sent to the ADS device that is to be specified. The receiver is addressed by means of the AMS-NetId and the port number (see also ADS Device Identification). The position within the receiver is specified by the index group/index offset or by the symbol name. Usually this is the input image or the flags area.
If the bEnable input is set to FALSE, no further signal transmission is carried out.
VAR_INPUT
VAR_INPUT
bEnable : BOOL := FALSE;
sNetId : T_AmsNetId;
nPort : T_AmsPort;
nIdxGrp : UDINT;
nIdxOffs : UDINT;
sVarName : STRING;
nSignal : BYTE;
nLowerLimit : BYTE;
nUpperLimit : BYTE;
tCycleTime : TIME := t#0s;
bSendNow : BOOL;
END_VAR
bEnable: Enable function block.
sNetId: AMS NetID of the ADS device to which the value is to be transmitted. (Type T_AmsNetId)
nPort: AMS port number of the ADS device to which the value is to be transmitted. (Type T_AmsPort)
nIdxGrp: Index group within the ADS device into which the value is to be transmitted.
nIdxOffs: Index offset within the ADS device into which the value is to be transmitted.
sVarName: Symbol name within the ADS device into which the value is to be transmitted.
nSignal: Variable whose value is to be transmitted.
nLowerLimit: Lower limit value.
nUpperLimit: Upper limit value.
tCycleTime: Cycle time in which the input signal is examined to see whether it has exceeded the limit values.
bSendNow: The value is transmitted immediately in response to a positive edge.
VAR_OUTPUT
VAR_OUTPUT
bBusy : BOOL := FALSE;
nLastSignal : DWORD;
bError : BOOL := FALSE;
nErrorId : UDINT := 0;
nErrorCnt : UDINT := 0;
END_VAR
bBusy: The transmission is active.
nLastSignal: Most recently transmitted value.
bError: An error occurred during the transmission.
nErrorId: Error number if an error has occurred.
nErrorCnt: Number of transmission attempts that have returned faults.
Requirements
Development environment | required TC3 PLC library |
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TwinCAT v3.0.0 | Tc2_DataExchange |