My new router will have two X axis motors - Nema23/SY60 from Zapp - driving ballscrews via HTD belts and pulleys. I'm thinking now about two aspects of this setup. I shall be using a CSMIO-IP/M, and I know about its limited support for this kind of dual-axis setup.
1. I shall be using EM806 drivers. These have an autotune facility for setting various internal parameters. I'm not sure how this would work in a dual-axis setup. You will only be able to tune one drive/motor combination at a time. I presume that this has to be done in the final hardware configuration (i.e. with ballscrew connected) but if the driver tries to move the gantry, the other ballscrew will be fighting it. However, if the other ballscrew is disconnected, the gantry will be driven by just one ballscrew and while I know that the gantry will move happily in this situation, it's not quite the load that the driver and motor will see in normal operation. Does this matter? I'm quite keen to get this right, as I have taken on board all the warnings about using the stall detection features to feed back and stop the machine if there are problems and I am assuming that the autotune will also help set the right parameters for the stall detection feature. Which brings me to the second question:
2. I can wire the fault outputs into the e-stop circuit so that the Pilz safety relay will trip. This will be wired to send a stop signal to the CSMIO as well as dropping the ENA signal to the drivers and switching off mains power to the driver/motor power supply. However, in the case of a fault, there will be some slight delay (10-20msec?) while the relay operates. I could wire the fault signals directly to the CSMIO (I believe) for much quicker response, but in this case I am relying on CSMIO firmware for correct operation, and there seems to be a feeling on this forum that you don't rely on firmware/software for safety-critical operations.
Am I worrying about nothing? My first router is a machine with so much flexibility and built-in weak points that none of this matters, but this new machine with welded steel structure and so on looks like it could do serious damage to itself and anyone in the vicinity if something goes wrong.
I run a slaved axis without the fancy tuning just a pair of 23's and apart from homing seperately to ensure correct alignment at start, no other precautions, if slaving I would think the tuning needs to be identical whatever the complexity of the system.
However I did play with the idea of linking with double pulleys and a timing belt to keep in sync in case of problem, and also double pulleys on drive with two four fanned blades synced centrally 45 deg off sync so any deviation of 45 deg rotation would collide/contact forming connection and forcing an E stop, s well as providing visual assurance to alignment preventing damage. In the end I decided to go with my ears and a sprint.
Last edited by lucan07; 04-06-2016 at 10:46 AM.
I am running a DB25 setup just a cheap 5 axis chinese bob and 4 DM542 drivers with 425 oz 23's, they are tuned identically and synced in mach3 it keeps them synced and I have had no problems at all losing steps. Only on initial setup of slaving one hiccup but that should be done before connecting drive screws so my own silly fault, if you try this ensure your ready with the E stop. I have a park routine away from homing where I can use a straight edge to check, and at first checked slave alignment regularly but now rarely as I have never found any slippage.
Last edited by lucan07; 04-06-2016 at 11:56 AM.
I bought the EM806 digital drivers as a modern alternative to the older M542 analogue drivers to make use of the digital drivers' features, mainly resonance control and stall detection, which is what my question was asking about. In brief, in a dual-axis setup, do you disconnect one ball nut while tuning the other axis, just take the target motor's drive belt off, or what? And should the driver's fault signal go back to the motion controller (quick response but relies on motion controller firmware to stop machine) or safety relay which will respond slightly more slowly but more reliably?
A quick scan through the software manual for EM drives page 18 step 2 states among other things that
"It is very important to make the Phase and Amplitude phase adjustments at the proper test speeds with an unloaded motor."
I could find no information particular to slaving, would therefore assume that tuning a slave motor different to its master would be counter productive reading Mach3 documentation states slave should be tuned identically.
Also (sorry if this is advertising for the opposition) but just saw this post on another forum and might be place to get best information.
Leadshine technical support available on CNCzone.com
Leadshine is glad to announce that we will start to provide technical support on CNCZone to users who have bought from us directly, or through our authorized distributors out side of China
Last edited by lucan07; 05-06-2016 at 11:45 AM.
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