![]() At this moment, I can open the VISA panel and see on his attributes that "Is Port Connected" has an "Invalid Property Value" on his current value.Īt this point, I tried some examples found on modbus library or on topics given by labview community and It always starts the same way : I just have to choose "Com 1" for the visa ressource name before the system detect the instrument and so I can finally choose "ASRL1::INSTR". The equipment you have should have documentation describing which modbus functions should be used to communicate.I'm currently trying to establish a communication between a Superflow SF1020 bench and Labview thought a Modbus protocol and I'm meeting a few troubles.įirst of all, the device can be seen by MAX properly only when i just rebooted the computer. It could be that addresses 1 through can only be accessed from a read input registers command. The focus here would not be the entire protocol but just start with understanding the memory map in Modbus and some of the basic function calls. I highly suggest you read up a bit on the basics of Modbus first before you dive in and try to communicate. Although the register def file is pretty cryptic (a nice secret decoder ring would be nice ), it looks like address 1 through 35 can be accessed with a read function and 201 through 203 from a write holding registers command. You could use a known Modbus master like Modpoll to help you troubleshoot the communication. I would first try to read 1 word at the first address and see if you can get some data from the device. The examples that ship with the NI Modbus Library are probably not going to work without some modification to the reading and writing. I know that Modbus I/O Servers supports RTU but have never used it myself. If you have Labview DCS or RT, you could use the Modbus I/O Servers. ![]() The NI Modbus Library supports RTU and ASCII. Next thing to find out is if the unit your trying to communicate to is a master or slave. ![]()
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