Drive Group and Drive System
In Sinamics, each individual control unit has it’s own drive group. Multiple drive groups can be combined into a drive system which might be controlled by a higher level motion controller to co-ordinate movements but each control unit will only know about the components located in its drive group.
Standard Topology of a Drive Group
In the standard configuration, you would connect X100 of your Control unit to X200 of your first drive. Then you would daisy chain from X201 of that drive to X200 of the next drive. Motor encoders (be they attached via SMC, SME or just drive-CLiQ) would be attached to X202 (or X203 for the second drive on a motor module). The infeed (if it has drive-CLiQ) can be inserted in the daisy chain or connected separately to the CU (i.e. through X101).
You are not required to place all drives in the group on the one daisy chain. However, any daisy chain that exists must follow the X201 -> X200 pattern.
The standard topology doesn’t handle direct encoders. These can be attached to any free drive-CLiQ port in the group, but must be configured correctly using Starter.
Use of Hubs
Drive-CLiQ hubs can be used to minimise cabling and also to provide additional Drive-CLiQ ports for the connection of additional encoders and Drive-CLiQ devices. The device numbering convention works a little bit differently on hubs than you might expect so it is important to note the port number your device is connected to and cross-check this with your project.
Be sure to remember that you can only use hubs to connect devices which belong to the same drive group. Example: you have three drive-CLiQ motors: Motor 1, Motor 2 and Motor 3. Motor 1 and Motor 2 are in Drive Group 1 and Motor 3 is controlled by another CU in Drive Group 2. All three motors are located in the same spot on the machine and you would like to reduce the cabling back to the drive cabinet. If you put a Drive-CLiQ hub in, you could only connect Motor 1 and Motor 2 to it and it would belong to Drive Group 1. Motor 3 would still have to be cabled back to the cabinet. If the cabling is long enough that saving one run is worth the cost of the hub this might be worth it. However, it makes more sense to try to re-arrange your drive groupings so that Motor 3 is also in Drive Group 1 and can be connected to the Hub.
The Drive-CLiQ topology is traversed as a depth first tree, with the control unit as the root. In the standard topology (ignoring infeeds), the CU would be numbered 1; the first drive 2; second drive 3 … (n-1)th drive would be numbered n and its encoder would be device n+1. As encoders are the last node on any branch, the traversal would return to the (n-2)th drive and its encoder would be device n+2 and so on.