Setting Up Profibus

BrendanDixon

Member
Join Date
Oct 2012
Location
Durban
Posts
19
Hi All,

Firstly I do not know much about profibus. But have allot of machines using it.

I have a machine that has Siemens 840D cnc system and has a jack with a profibus connected Baluff measurement sensor the problem is that the CPU is not getting a reading from the sensor. We have tried replacing the sensor and checked the cable but cannot get the system to read the sensor. I see the sensor has dip switches for setting the address and if I look at the PLC program hardware configuration it shows the sensor with the same address that it has been set to. Is there anything else I need to take a look at?

I am not sure if we just had to set the address and plug in or is there something else?

Hardware 1.jpg Hardware 2.jpg
 
Last edited:
Disclaimer: I dont know Sinumerik 840D, but it looks similar to STEP7.
If similar to STEP7, then check the hardware diagnostics.
If it says that the node is unreachable, then check the dip switches (are you interpreting them correctly ?), check the connectors at both ends.
If that doesnt reveal anything, then check the encoder with another system. If that works OK, then there is a problem with the profibus port on the 840D.
 
Hi Jesper,

The 840D is basically a S7-300 PLC and CNC combination unit and it is configured in Step7

On the CPU is has a DP Light flashing. According to the manual if this light flashes it means the profibus is configured properly and that there is a device missing. I am not sure how to do a diagnostic. on the HMI there are no errors.

The agent is now suspecting that maybe the DP Port on the CPU is faulty
 
Probably a silly question, but do you have termination resistor installed or the switch it the right position on the end connected to the sensor?
 
In Simatic Manager, right-click on the "CPU". Then choose "Hardware diagnostics".

also, what I said before:
If it says that the node is unreachable, then check the dip switches (are you interpreting them correctly ?), check the connectors at both ends.
If that doesnt reveal anything, then check the encoder with another system. If that works OK, then there is a problem with the profibus port on the 840D.

These are my experiences for when a functioning profibus system "suddenly" goes bad:
80 % of all profibus errors are badly terminated cable(s) in one or more connectors.
10 % are bad DP slave devices.
5 % are defective connectors.
5 % are other problems.
 
Last edited:
I have had this happen and switched all devices off starting at the controller then went and switched them back on in the opposite order.
 

Similar Topics

We have been grinding for too long trying to configure a node in our profibus network. A Profibus card in our GE Rx3i PLC is the master. We have...
Replies
1
Views
1,776
Hello, I am very beginner in PLC world when it comes to networking. For student exercise I need to investigate how to set up communication...
Replies
3
Views
2,675
Hi. Im trying to setup a connection between a S7-300 and a TP170B through profibus. On the S7-300 i have a CP343-1 ethernet module for...
Replies
22
Views
9,077
I am facing a problem with softstarter abb which was communicated to s7400 via profibus as i had used related pdp22 gsd and...
Replies
0
Views
1,439
Hi guys, Just joined, had a bit of a browse and most people seem to know more than myself regarding PLC's which is a good start. Quick bit about...
Replies
4
Views
2,604
Back
Top Bottom