Transmission Verification

When transmitting commands to a DAQ Module, in many cases it may be extremely important to verify the reception of that command. Using a command to turn on or off any external electrical devices is one example, since the failure of that function may adversely effect the operation of the application as a whole. Fortunately ModCom is designed to allow each command to be verified and retransmitted if it failed to be received by the target DAQ Module.

When using the Transmit Command function in a Script, Conditional, PushButton, InputWindow, etc., there is an option to "Send the response to this Screen Object". Typing in the name of a Screen Object into this box notifies ModCom that a response is expected from the DAQ Module which is the target of this command. In this case, ModCom will automatically watch for a response and if one has not been received within 0.5 seconds, the command will be retransmitted. This procedure will repeat itself every 0.5 seconds until receiving a response, which will indicate that the DAQ Module successfully received the command. If no response has been received within a timeout period equal to one minute, an error box will pop up indicating that the DAQ Module is not responding.

Note, the Screen Object listed in the "Send the response to this Screen Object" box does not have to actually exist in the project. This could be a fictitious name such as "Dump" or "Delete" if not wanting to show the response in a window on the screen. ModCom simply interprets the presence of a name in this box as an indication that a response is expected.