modbus communication

Franky 2017-09-29

Hallo Community

we have a problem with the modbus communication. We send a Signal e.g. Door open from a Siemens LOGO to the UR. This way is running.
But if we send an output Signal like open the door we can´t recive it on the LOGO. The robot is config as a client. We have test a lot of things but we can´t find the wright way. Maybe someone here can help me.

Greetings from Germany

matthewd92 2017-09-29

@Franky welcome to the community. A couple of thoughts come to mind as these are issues we've had in the past.

First, are you using discrete output bit or a byte register for the output? If you're using a register are you setting it to the correct byte for the output you want to turn on?

In either case is the address for the bit or the byte correct. I've never used the Siemens system but I know some units use the same addressing for inputs and outputs and some use diffferent ranges. We used a system a few years ago where discrete inputs were between 0 and 511 and discrete output addresses were 512-1023. Until we figured that out it wouldn't work. It was the same with the register values as well.

Franky 2017-10-16

@matthewd92 Thanks a lot for your comment. We change the SPS now to a Siemens S7 1200. Now the communication is running over Profinet. That´s realy fine. We can send a lot register Bits and recieve them. That´s fine.

matthewd92 2018-04-25

@Franky I am trying to hook up a Siemens S7 1215C to a UR10 using Profinet and am having issues getting the PLC to find the robot. I keep getting an error that the robot is unreachable. I know the robot is on the same network, can ping it and it responds. Did you have any issues or is there any insight you could share with us to get this running? We have the other portions of the cell now hooked up and operational and just need the robot to complete the communications.

Franky 2018-04-25

Hallo Matthew92. Check out this german Video Tutorials. https://youtu.be/F6rHbVb6Y10 This is part one. https://youtu.be/MhUDFoAdZNc This is part two. I use it. With this Information the UR10 is communicate with the S7. I Hope I can help you with this links.