Centroid Oak with Rexroth IndraDrive M servo drives

[ShawnM]

I did a search on the forum for Rexroth drives and one member started a topic about wiring them to an Oak controller. He never followed up his posts with any results.

I have a possible retrofit of a Weeke BHP200 5X12 CNC router with two Rexroth IndraDrive M servo drives on the X and Z axis and a Rexroth IndraDrive C servo drive on the Y axis. All motors are also Rexroth. I found a manual online for the HCS02.1E series drives on the machine, linked below, and it shows on page 15 of the PDF all the supported operating modes and here they are:

Supported Operating Modes
The drive firmware supports the following operating modes:
• torque/force control
• velocity control
• position control with cyclic command value input
• drive-internal interpolation
• drive-controlled positioning
• positioning block mode
• synchronization modes:
• velocity synchronization with real/virtual master axis
• phase synchronization with real/virtual master axis
• electronic cam shaft with real/virtual master axis
• electronic motion profile with real/virtual master axis

I am assuming I can use the Oak in either Velocity mode or Position mode to control these drives. Any thoughts?

I sent a PM the the member who posted about Rexroth drives and have not received a response yet.

Anyone else have any input or suggestions as to which mode is better or which one to try?

Here's a link to the drive manual for reference if needed.

https://www.convertingsystems.com/uplo ... hcs031.pdf

[aamir]

[centroid467]

The first thing I would do is verify that they have the closed loop firmware with servo functionality as broken down in Chapter 4.1. From this manual, I don't see any way to configure the digital inputs for the Oak's position control signals so I think you'll be limited to velocity mode.

[ShawnM]

Thank you, when he gets the machine powered up I'll check the drive firmware against the table in the manual that you referenced.

[ShawnM]

The first thing I would do is verify that they have the closed loop firmware with servo functionality as broken down in Chapter 4.1. From this manual, I don't see any way to configure the digital inputs for the Oak's position control signals so I think you'll be limited to velocity mode.

The firmware in the drives is "closed loop" only and not "closed loop + servo function". The firmware ends with D5-1-NNN-NN. The drives are currently setup to use "position mode lagless, encoder 1" but have the option of:

- torque control
- velocity control
- position mode with encoder 1
- position mode with encoder 1, drive controlled
and a few others.

Is this still a possibility with the Oak or is there a better controller for these drives?

[centroid467]

Honestly, that manual does not explain anything about the modes other than that they exist. It also calls out sections that do not exist in the document so I cannot be certain that the modes would function the way I expect. But, I found all sorts of documents on the Rexroth website that might help. They've got listings of other related documents that could help decipher the codes to see what you can do with the installed configurations. Here's where I started: incredibly long URL

I would start with R911309636 and the manuals referred to on page 12 of that document to identify all components and their capabilities.

However, given that they have the basic closed loop firmware and therefore requires encoder feedback, I would expect velocity mode to work with the Oak if it can put out the encoder signals to the Oak.

[ShawnM]

Thanks again for the info. I have many manuals that I downloaded from Rexroth and there's a lot of info out there.

After further digging into the machine it appears that these Rexroth drives use Sercos which is a fiber optic connection to the controller which is a PCI card inside the PC on the machine. The machine is a 2007 and sometime after than they switches to EtherCAT but unfortunately this machine uses a fiber optic connection to control the drives. It's very similar to EtherCAT in that the drives are all daisy-chained together with a single fiber optic cable.

There are two other connectors on the drive, X31 and X32, that are for inputs and outputs so I'm checking to see if these connectors will allow me to "wire" in a control signal. The only other wired connectors on the drive are for the motor power, motor encoders, motor brake, the external braking resistor and a signal to monitor the motor temp.