Ultra 3000 w/ DeviceNet

[Bitmore]

The bugs are now talking
Ken is right! Cercos ring is the way to go!
I have had a few projects with them, and the motion command structures are awesome! There is nothing that compares to the one button commissioning function! Just provide the memory!

bitmore

 

[Steve Crotty]

I dont see the point of going from SLC / Indexing Ultra 3000 to a SLC / DeviceNet Indexing Ultra 3000.

The reason why your rep wants you to switch to Control Logix is that it is very powerful for motion control. As soon as you cut control logix out of the loop im not sure what you are really gaining? Do you really want to be able to communicate with the drive over deviceNET? Why?

If you were building the system from scratch I could see why you might want to go with the devicenet option.

 

[ChuckM]

We want to switch because there are 4 drives on this machine and each axis makes at least two indexed moves per cycle. The current communication method uses a Quartech communications bridge and it takes sometimes up to six seconds to send the index pos/dist and host index to the drive. Six seconds, four drives, two indexes each drive per cycle... It adds up quickly. Also because the communications are so slow, it is difficult to get two axis to operate at the same time. We estimate that if we could communicate with the drives faster we could double the output of the machine.

 

[Ken Roach]

I just finished a project using the Ultra 3000 Host Protocol to replace a Quartech OIT panel on four drives. It took me a week to sort out two months of another guy's hard work. My comment to the customer was "If you'd used DeviceNet, we would have been done two months ago".

Sending index values to the Ultra 3000i is very simple on DeviceNet; you fill in an Output memory block in the 1747-SDN with the value and a parameter pointer, then trigger the "write parameter" bit. Once the "Parameter write successful" bit comes back in the Input data table, you're done. I have never had to calculate how long it takes the Ultra 3000 to accept and apply the value; I presume it is in the 10-20 millisecond range.

The big challenge when using the SLC-5/0x as a controller with the Ultra 3000 is, as you have already seen, the fact that the Ultra likes its values in Counts, sometimes in very large numbers of Counts.

Because the SLC doesn't support 32-bit integers, that's the big hurdle.

Search this Forum for some examples of using the 32-bit Resultant registers in the SLC to obtain large values, or to convert a Floating Point value into a long integer using ladder logic.

I am doing an Ultra 3000i / CompactLogix L32E application test next week. We might have to open up another thread to talk about Chuck's application specifically.

 

[ChuckM]

I'm glad I'm not the only one in this boat. The Quartech product is pretty neat and to the point, but just not as fast as one would hope to see. And as Ken stated, the only hurdle I am seeing is the 32bit math part of it. While the Micrologix demo I have can do long integers, the 5/03 that I plan to use can't. I'm tempted to just buy a devicenet scanner for my SLC and see what I come up with.

I have some more questions but I promised myself that I would put this project out of my mind and enjoy some good Canadian whiskey this weekend.