Helloo....i have a vacuum pump and controller....the controller can display the pump data and control the pump on/off, set point and etc....my question is how can i sniff the data of that the pump from the controller and display it on an HMI that connected to a plc.....the information that i know for now is the pin rx,tx and gnd from the controller.....the pump controller use rj11 connector.....idk what protocol its use but i think its ASCII......my plan right now is to buy a Y connector rj11 and connect it to my plc...need some advice.....

 

Assuming the communication protocol is half duplex (which most protocols are), you could use an RS-232 tap device, such as this:
https://www.digikey.com/en/products/detail/advantech-corporation/BB-9PCDT/4759754

Alternatively, you could use an RJ-11 Y splitter and make your own RS-232 tap using two diodes (or one diode and one resistor) on the TX and RX lines (pins 2 and 3) such as shown here:
https://www.lammertbies.nl/comm/cable/rs-232-spy-monitor

Regardless of which method is used to combine the TX and RX lines into a single RX line for sniffing, I recommend first testing with a computer and a terminal emulator program to try to make sense of the protocol. Custom ASCII protocols are sometimes documented in the user's manuals or other documentation (such as communication manuals) of devices. You may have luck looking up the documentation for your vacuum pump and controller.

 

Assuming the communication protocol is half duplex (which most protocols are), you could use an RS-232 tap device, such as this:
https://www.digikey.com/en/products/detail/advantech-corporation/BB-9PCDT/4759754

Alternatively, you could use an RJ-11 Y splitter and make your own RS-232 tap using two diodes (or one diode and one resistor) on the TX and RX lines (pins 2 and 3) such as shown here:
https://www.lammertbies.nl/comm/cable/rs-232-spy-monitor

Regardless of which method is used to combine the TX and RX lines into a single RX line for sniffing, I recommend first testing with a computer and a terminal emulator program to try to make sense of the protocol. Custom ASCII protocols are sometimes documented in the user's manuals or other documentation (such as communication manuals) of devices. You may have luck looking up the documentation for your vacuum pump and controller.

thanks broo later i;ll try it