The timeout is only used to provide enough time for the other device to get a valid message, act on it, and respond to it in a reasonable amount of time without the calling program to wait endlessly for a message that may never come such as in your case due to a corrupted transmission. If it's noise, increasing your timeout won't help because if the noise corrupts the message, you will never get a valid message back.
Labview modbus code code#
(You may want to put some additional code in there to be able to stop the loop on other conditions as well such as only reattempt the MB WR 2 or 3 times before just returning an error.) In the event that the timeout error occurs, you have the modbus write/read happen again. You could put the modbus read in its own loop. Īre you getting popup error messages for this timeout? Don't forget to wire up your error wires! Don't use a shift register but just regular tunnels for the error wire otherwise if an error happens once, it will prevent the modbus read/write from ever executing properly again. In case it's useful, I've posted a simple version of code which generates the problem. I Declared the 9 and 10 pin as Tx Rx Pins in the code the Rest of the Code is.
Labview modbus code serial#
My question: is there a coding trick i can use to reconnect in the event that a corrupt signal occurrs (or some other problem which results in the intermittent appearence of the error 6101)? I've increased the timeout value on the MB Serial Master Query sub vi, but this hasn't helped. It should be noted that Modbus is a software protocol and not a hardware. I am now having the problem with an RS 485 line in the noisy environment, which should be very stable in noisy environemnts. JKI Softwares VI Package Manager (VIPM) makes utilizing and dispersing a NI LabVIEW. Removing the USB cable from the noisy environment eliminated the problem. We have studied about labview and an additional software VI package Manger. Below screenshot will give you an idea about my LabVIEW project. In the past, I was getting this error as a result of RF noise corrupting the signal in the USB connection to the instrument. Anybus X-gateway - EtherCAT Slave - Modbus RTU Slave.
This code seems to be associated with the MB Serial Master Query sub VI. The code works as desired for a while, but will intermittently stop executing and give a timeout error, code 6101. I am trying to acquire data from an instrument using MODBUS RTU protocol. I am experiencing a problem which other users have reported, but for which little useful information has been posted:
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