Has anyone done a successful [-LARGE-] PLC-3 system conversion to Logix while retaining all of the existing 1771-I/O? My main concern at this point in time is putting together an architecture that will work without scan time and hardware issues for an “UM” proposal.
To be more specific and bring you into our abyss, we have (2) two individual PLC-3 hot-backup systems that have about 40 chassis worth of I/O on each PLC spread across three scanner modules in each PLC system. (12 Channels / Networks each PLC – 24 channels total) The total I/O count doesn’t come close to Logix max. capability.
It would be desirable to bring all of this into one Logix processor using a primary/secondary setup. Sounds easy enough, but there are some concerns where the 1756-DHRIO module are concerned.
If we swap blue hose from all of our scanner module channels (24 in all) and apply them directly to the DHRIO module(s) ports we end up using 12 of the DHRIO modules. Each port would then support anywhere from two to ten drops based on existing routing of blue hose. We may be able to better this by combining some blue hose runs in the field increasing the drops on some channels. Anyway,,,, I know Rockwell’s claims of “Processing speed” – but is this a realistic application were scan time (RPI/NUT) is concerned? Has anyone out there tackled such a beast using the 1756-DHRIO? (P.S. Blue Hose = Belden #9463)
The use of redundant rack numbers is also a concern. Based on limited literature it seems like it may be possible as long as the same rack number is not used/configured on the same DHRIO module/network. Not sure…yet.
The amount of drops/racks off each channel is also a concern. (32-?) It just doesn’t seem realistic. We would feel more comfortable staying below (16). Not sure….Anyone exceeding 16?
Sorry for being long winded, but the application is quiet large and we need to get it right the first time. Any experienced advice would be appreciated so that we may get this project off the ground on the right foot. We are in contact with Rockwell direct. But,,, we would like to here about some real world experience. In our eyes, nothing speaks like experience. That’s when it all crawls out and is exposed.
(Software will be the next migraine. Don’t care to think about it yet.)
Thanks
To be more specific and bring you into our abyss, we have (2) two individual PLC-3 hot-backup systems that have about 40 chassis worth of I/O on each PLC spread across three scanner modules in each PLC system. (12 Channels / Networks each PLC – 24 channels total) The total I/O count doesn’t come close to Logix max. capability.
It would be desirable to bring all of this into one Logix processor using a primary/secondary setup. Sounds easy enough, but there are some concerns where the 1756-DHRIO module are concerned.
If we swap blue hose from all of our scanner module channels (24 in all) and apply them directly to the DHRIO module(s) ports we end up using 12 of the DHRIO modules. Each port would then support anywhere from two to ten drops based on existing routing of blue hose. We may be able to better this by combining some blue hose runs in the field increasing the drops on some channels. Anyway,,,, I know Rockwell’s claims of “Processing speed” – but is this a realistic application were scan time (RPI/NUT) is concerned? Has anyone out there tackled such a beast using the 1756-DHRIO? (P.S. Blue Hose = Belden #9463)
The use of redundant rack numbers is also a concern. Based on limited literature it seems like it may be possible as long as the same rack number is not used/configured on the same DHRIO module/network. Not sure…yet.
The amount of drops/racks off each channel is also a concern. (32-?) It just doesn’t seem realistic. We would feel more comfortable staying below (16). Not sure….Anyone exceeding 16?
Sorry for being long winded, but the application is quiet large and we need to get it right the first time. Any experienced advice would be appreciated so that we may get this project off the ground on the right foot. We are in contact with Rockwell direct. But,,, we would like to here about some real world experience. In our eyes, nothing speaks like experience. That’s when it all crawls out and is exposed.
(Software will be the next migraine. Don’t care to think about it yet.)
Thanks