TC_SysLatency

TC_SysLatency 1:

The "TC_SysLatency" function block allows the current and maximum latency time of a TwinCAT system to be determined. This function corresponds to the display of latency time in the TwinCAT system menu under the real-time settings. Internally, an instance of the ADSREAD function block is called.

VAR_INPUT

VAR_INPUT
    NETID       :T_AmsNetId;
    START       :BOOL;
    TMOUT       :TIME := DEFAULT_ADS_TIMEOUT;
END_VAR

NETID: It is possible here to provide the AmsNetId of the TwinCAT computer whose latency time is to be determined If it is to be run on the local computer, an empty string can be entered.

START: The function block is activated by a positive edge at this input.

TMOUT: States the length of the timeout that may not be exceeded by execution of the ADS command.

VAR_OUTPUT

VAR_OUTPUT
    BUSY       :BOOL;
    ERR        :BOOL;
    ERRID      :UDINT;
    ACTUAL     :UDINT;
    MAXIMUM    :UDINT; 
END_VAR

BUSY: When the function block is activated this output is set. It remains set until and acknowledgement is received.

ERR: If an ADS error should occur during the transfer of the command, then this output is set once the BUSY output is reset.

ERRID: Supplies the ADS error number when the ERR output is set.

ACTUAL: The current latency time of a TwinCAT system in µs.

MAXIMUM: The maximal detected latency time of a TwinCAT system in µs.

Requirements

Development environment

Target system type

PLC libraries to include

TwinCAT v2.8.0 Build > 732

PC or CX (x86)

TcUtilities.Lib

( Standard.Lib; TcBase.Lib; TcSystem.Lib are included automatically )

TwinCAT v2.10.0 Build >= 1301

CX (ARM)