Ron

thanks you, I found a software to simulate slave and everything is working great! Thanks for the help, didn't used it this time but defiantly keeping that in mind

Hi all, Im trying to understand how to communicate through modbus RS485 with a V700 PLC. In the end I need to connect to a blower type device but let's forget that for now (I dont have it available anyway). Im trying to successfully send and receive from a PC using a USB to RS485 adapter (USB to DB9 to RJ11) - DB9 pin 2 is connected to pin 1 in the RJ11 and DB9 pin 1 connected to pin 6 on the RJ11, is that correct? Now for the program (attached): I configure the TCP port for online view and download, then configure port 1 as RS485 with the default settings. BTW the dipswitches are configured as a RS485 termination is that right? Then did 1 net to read register (function 3) and 1 net to preset register (function 6), only trying to read and write 1 bit(byte?), same as would be with the blower device. Im using a program called ComTestPro for modbus devices to try and act as the blower to read and write the first bit. I get the following error "Incorrect function code in response", for both read and write Does anyone know what's the problem? any help/clues are greatly appreciated TestModbus485.vlp

I "modified" the cable I use and it worked! thanks so much kratmel

Ok thats a good idea.. any easy way to check/solve? thanks

Hello all, I using a Samba 3.5 to send and receive data to/from a weight indicator. I only have (for now) 1 com port on the samba so I cant use the online test while connect to the indicator, so I used a terminal on my PC to "replace" the indicator when connected to the samba and "replace" the samba when connected to the indicator. The indicator has 2 comm modes - response to a "W", or send the weight automatically ~5 times a sec. When Im using the terminal to talk to the samba/indicator everything works great - the samba sends "W" and it's received on the terminal, and when I reply with "+XXX.XXX" the samba receives it (shows on the monitor in the info mode) and displays it in the HMI like I programmed. When I connect the indicator to the PC I can send "W" and receive "+XXX.XXX" as expected. All this is great and all, but somehow when the indicator is connected to the samba nothing is received (on the samba end). even in the info mode monitor nothing is showed in the Rx box. Not in respose to "W" and even in the auto send mode where it sends the weight without any command. Now, as I understand (could be wrong), no matter how I program the samba, when it receives data through the com port it shows on the serial monitor, right? so how can it be that nothing is received? Thanks:) SM35RA22_WeightCheck2.vlp