You can Bank on it...
GaryS said:
the power supply requirements is based on the power requirements of the modules the power supply is powering. You can have multiple power supplies in the same rack...
GaryS,
If by "rack" you mean CompactLogix "Bank", then that would not be correct. You may only have one 1769 Power Supply per Bank.
For a 1769 based CompactLogix System...
Bank 0 may only have one 1769 Power Supply.
The controller must reside in Slot 0.
There can be a maximum 3 x I/O modules between the controller and the 1769 Power Supply.
On the other side of the 1769 Power supply there can be a maximum of 8 x I/O modules.
Therefore, the maximum number of I/O modules for Bank 0 = 11
Any more than 11 x I/O modules in Bank 0 is invalid.
If a 1769 CompactLogix System requires more than 11 x I/O modules then a new Bank must be created with its own 1769 Power Supply. Additional Banks, and their 1769 Power Supply, must be connected together with one of the 1769 expansion cables.
Bank 1 does not have a controller in Slot 0
Therefore, for controllers that support the maximum of 30 I/O modules (certain L3x controllers)...
Bank 1 may have a maximum of 8 x I/O modules either side of a 1769 Power Supply.
Therefore, Bank 1 may have a maximum of 16 x I/O modules in total.
Any more than 16 x I/O modules in Bank 1 is invalid.
Bank 0 = 11
Bank 1 = 16
Total so far = 27 x I/O modules
So, Bank 2 may then only have 3 x I/O modules, reaching the total of 30 x I/O modules for the entire System.
Bank 2 also requires a separate 1769 Power Supply.
Any more than 3 x I/O modules in Bank 2 is invalid.
Other CompactLogix controllers support less Banks and less maximum I/O modules per System.
The above is an example outlay of a maximum of 30 x I/O modules. The actual maximum will be determined, and as mentioned, by the 1769 Power Supplies used and their current capacity. Also, by the I/O modules selected and their current draw and minimum distance rating to the Power Supply in their Bank.
To recap: A second 1769 Power Supply cannot be added to any Bank for additional power, but may be added with a new Bank and extension cable. Each Bank's Power Supply only provides power for that Bank. It cannot provide additional power to adjacent Banks.
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GaryS said:
...Local modules means connected to the local rack the same rack the CPU is installed in...
Or, a local module may be an I/O module that is installed in an additional Bank, where no controller is installed i.e. any of the possible maximum 3 x Banks.
GaryS said:
...Ethernet I/O would all be classified as remote and the max number would depend on the processor limits...
For the newer CompactLogix controllers, the number of Ethernet devices added to a System are counted as "Nodes". Each controller has a Node limit. Only Ethernet device that are added to the project's I/O Configuration are counted against the Node limit. These are indeed external devices and have nothing to do with the local I/O modules added to Bank 0, or subsequent Banks, if applicable.
GaryS said:
...in case of multiple I/O networks each network would have a limit of the max for a subnet. I think it's about 250 I try to limit my number to less than 200 incase I need to add 1 or so.
Modern Industrial Automation and Control Systems (IACS), utilizing Converged Plantwide Ethernet (CPwE) architecture, do not conform to the Ethernet standards of old, such as those used in Domestic and commercial settings, where IP addresses are dished out within one range until there are no more. In CPwE, Segregation is achieved primarily using IP Subnets and VLANs. By designing the overall system into individual Cells/Zones, you greatly reduce the number of nodes per Subnet or VLAN. A properly designed and segregated CPwE architecture will typically not have IP addressing assigned up into the hundreds. In fact, within several relatively small Cell/Zone areas, it is quite common to see the same IP Subnet range used repeatedly. NAT appliances are then used to translate the Cell/Zone addressing to the wider network.
By today's IACS standards, you do not keep assigning Plantwide 192.x Class C addresses up into the hundreds and beyond. I still see lots and lots of references to users implementing "Office" Ethernet standards in Industrial settings, using 192.x Class C addressing where networking appliances, such as routers, typically allow up to 254 devices to be connected together. 10.x Class A addressing is more the norm for Industrial CPwE architectures where you want to introduce multiple Subnets/VLANs, each facilitating up to 254 devices, or Nodes, each, but typically not reaching anywhere near that limit.
This is not a "you must do this" lesson. It's just how it's done nowadays and what is considered good practice and the industry norm.
Regards,
George
