Hello
we have inserted a SEW DFC40A drive in our configuration and we are encoutering a powerlink communication problem with this device.
Our net cycle time is 800us and I think is too fast for the drive.
I think this because with 4800us is working correctly, but setting even 1600us i’m having a status BE LED ON.
From manual it means:
the problem is that our APC has three powerlink board full of devices that must runs at 800us and we have no possibility to add more boards or change cycle time.
Any idea? Is there a way to add an additional powerlink net running at a different cycle time?
from what I could find, SEW recommends (requires?) 2ms cycle time (generally I found “<= 4ms”) on some page there. Let’s assume it’s 2ms <= x <= 4ms for the sake of the rest of the post.
I can’t think of any possibility of getting anothter PLK MN into your system if you already exhausted all 3 interfaces for it.
What I can come up with and this depends on your current setup:
Why are you using 3 separate PLK interfaces right now and would it be possible to collapse them into one or two only, so the third can be used with >=2ms cycle times?
Since I don’t know your current setup and why it was chosen, my guess is:
You currently have some amount of PLK slaves that each have to run at 800µs cycle time. Since you can only use that cycle time for so many participants in a row, you split them into three separate lines.
What, if this is true, could be done: Use a hub and merge two lines
trying to disable DS402 mode → expecting SEW do not care on interpolation time, but we still had Moduleok set to FALSE and no data from drive. I was thinking to develop the entire function block using VELOCITY mode instead of PROFILE VELOCITY and sending messages via SDO’s. No chance
change various powerlink cycle time → no chance
in the end, I change powerlink topology: I moved all the axis and time critical modules to two slots, taking care of correct balancing ofthe networks using hardware configuration analyzer. At the moment: I have Servo network with estimated loop time around 680us, the other board 600us and the last at 400us.
Our configuration is full of servo and devices, so it is not very easy to change powerlink timing… We will reconsider the usage of these Sew devices.
