Profibus problem

Rocguy

Member
Join Date
Dec 2016
Location
Chicago
Posts
48
Hey guys, it's been a little while. I'm having a problem that I can't seem to figure out. I'm using a Helmholz FLEXtra® multiRepeater. 6 way. I connected to one port, a PAS 153 slave plc unit, out to a Yaskawa 1000 VFD. The out of that goes to in the input of another PAS 153 slave plc and, on to another Yaskawa drive. That works fine.
The problem is when I try to continue to another PAS 153, it bus faults the first two. I have triple checked the addresses to make sure of no conflicts. I have checked the address settings in the software to make sure they are set right. Surely I should be able to get more than just those 4 nodes connected to a port on the 6 way repeater??
 
Hey thanks for the reply! The resistor is built into the connector and, one thing I find weird is that the only way the first two work is if that last switch is in the OFF position even though it's supposed to be ON. When switching it, it bus faults. It doesn't seem to matter what position its in. I can't get the third set of nodes to work.
 
What data rate are you running the Profibus DP network at ? Is your total cable length compatible with that data rate ?

The Helmholtz repeaters, the PAS153 I/O adapter, and the Yaskawa V1000 Profibus DP adapter all appear to have no termination built into them, so you will use normal Profibus DP connectors with switchable terminators.

Profibus DP needs terminators at each physical end of the daisy-chain, so only two of the Terminator switches in your set of devices need to be turned on.
 
The data rate appears set at 115. The connectors do have on and off switches on them. You are correct. They are not built into the PAS or repeater. I would estimate total cable length at less than 100 feet.
 
115 what ? 115 kbps ? That is not a standard profibus speed as far as I remember.
Maybe you mean 1.5 Mbps ?


The terminators should like this:
Repeater-out (IN)(ON) ---- PAS 153 slave (IN)(off)(OUT) ---- Yeskawa 1000 (IN)(off)(OUT) ---- PAS 153 slave (IN)(ON).
 
115 what ? 115 kbps ? That is not a standard profibus speed as far as I remember.
Maybe you mean 1.5 Mbps ?


The terminators should like this:
Repeater-out (IN)(ON) ---- PAS 153 slave (IN)(off)(OUT) ---- Yeskawa 1000 (IN)(off)(OUT) ---- PAS 153 slave (IN)(ON).

Thank you very much for the reply.

I will have to double check that. I will be at work tonight and can clarify what it is. I am going off memory. I'm thinking that was Baud Rate?

I'm a little confused on what the beginning of your terminator check is saying.

The line coming from the repeater has one cable only. An out. Are you saying that switch should be off or on? Like I said, it's working with two machines so I'm guessing someone set it correctly. The last thing in the line is a VFD. It looks like that's missing from what you said. 2 PAS 153 and 2 Yaskawa VFD working. Trying to connect another PAS 153 and finally on to another Yaskawa VFD
 
it's working with two machines so I'm guessing someone set it correctly.

When I am troubleshooting industrial networks, I always check the low-level cable and termination first. When somebody says "it used to work so there's nothing wrong with it", then I check it twice.

From what you describe, you should have the Profibus connector termination switch ON at the Repeater, and at the last VFD.

Any connectors in between should have their termination switches OFF.
 
When I am troubleshooting industrial networks, I always check the low-level cable and termination first. When somebody says "it used to work so there's nothing wrong with it", then I check it twice.

From what you describe, you should have the Profibus connector termination switch ON at the Repeater, and at the last VFD.

Any connectors in between should have their termination switches OFF.

Ok, thank you very much. I will check that when I get to work tonight. That might explain why the last machine is currently working with the switch off. Maybe that first switch is set to off. I'm new to Profibus. I read in the directions that came with the switches that the last connector needed to be "on"

Am I correct thinking that 3 PAS 153 and 3 VFD from one feed off the repeater shouldn’t be a problem?
 
Last edited:
I'm a little confused on what the beginning of your terminator check is saying.
I may have confused you by assuming that there are connectors on the repeater.
If the repeater is the kind without connectors, but have terminals built-in, then there will be a switch on each side for activating or deactivating the termination resistors.


On the other devices, you use connectors with the termination resistors built-in.
Important, on these connectors there is an input (arrow in) side and an output (arrow out). If there is only one cable going into the connector, it MUST be on the input side. And the termination must be ON of course.
 
115 what ? 115 kbps ? That is not a standard profibus speed as far as I remember.
Maybe you mean 1.5 Mbps ?


The terminators should like this:
Repeater-out (IN)(ON) ---- PAS 153 slave (IN)(off)(OUT) ---- Yeskawa 1000 (IN)(off)(OUT) ---- PAS 153 slave (IN)(ON).

Ok sorry, yes I meant 1.5mbps. In the software it's listed as 1500 kbits for Baud Rate.

This is the exact repeater. https://helmholzsales.com/products/700-972-6aa02-flextra-multirepeater-6-way?variant=496958533

This is the connector going into the PAS 153 https://helmholzsales.com/products/700-972-0ba50-profibus-connector-easyconnect?variant=469078349

This is the connector used at the drive pack. https://helmholzsales.com/products/...onnector-axial-cable-outlet?variant=468707805

We have swapped out the connectors and re done the cable connections to no avail. Rechecked that all cables were in the correct order. In where in should be and out where out should be etc. Reverified all address settings again. Tried a new cable from the out of the last working drive to the In of the non working slave. We swapped all connectors in the backplane of the Slave PLC unit. We have swapped the Slave PLC (PAS 153) 3 different times.

All of this produces the same result. If you leave the OUT port of the last working VFD empty, the first two units are fine. As soon as you plug into the port, it bus faults the first two working units.

Terminating resistors are as follows. At repeater, ON all other switches set to OFF. I know the last one is supposed to be ON but, when you turn it on, It faults the other working units.

The only thing I can think of that I haven't tried is swapping out the repeater. I know it's easy enough to say try it. The problem is, I don't want the supervisor looking at me when it knocks out a whole production line. I may be better off suggesting that to the electrical supervisor in the morning and they can try it on day shift.

I'm open to all suggestions.
 
Renting a profitrace is also possible. We rented one when we had a problem which we just couldnt knack. With the profitrace it was quickly established that the common ground was floating, something that would have been near impossible to figure out by other means.
These things are remarkable. I dont do much Profibus anymore, but if I did I would definetely buy one.
 

Similar Topics

Dear All, I have a KUKA Palletizer machines having Iconics Genesis SCADA installed on its PC. It remained closed for about 7 to 8 years. We are...
Replies
0
Views
944
Hello guys, I have problems with the Porfibus communication to my regulator Siemens Sipart DR 21and my PLC rockwell 1756-L161. So, for the...
Replies
8
Views
2,085
Hello to all, I have a strange problem with establishing the communication between WinCC HMI station and the rest of Profibus network. We have...
Replies
14
Views
3,822
Experts! Need Help In My application i have Siemens CPU 316 WITH APPROX 28 PROFIBUS NODES (including Simovert Master Drive -14N.o.s & IM153 &...
Replies
5
Views
4,709
Hi guys, I have a machine that has been acting up a few times lately. It looks like it "forgets" it's position. The position comes from a...
Replies
1
Views
1,431
Back
Top Bottom