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"having these numbers off can lead to missed steps or no movement."

No, having these numbers too low can lead to missed steps or no movement.

Most common issue is too short step time, this can led to erratic
behaviour or no motion at all.

Too short direction setup or hold can result in lost or gained steps at reversals
but since reversals only happen at near 0 velocity (and consequent long times
between steps), there is little cost associated with setting quite long direction
setup and hold times (that is 20000 ns is probably OK for anything...)

I did a little playing around here colab.research.google.com/drive/1UHn0M74...8Aln1z77?usp=sharing with what I read in this paper www.researchgate.net/publication/2926698..._Numerical_Algorithm. Basically you give the algorithm a starting position, radius, angle, angular direction, and ending angle and it generates a matching clothoid curve. You don't know the ending position until the computation is finished so it will have to be translated after. I'm not sure if this would cause problems that couldn't be dealt with.

There could be other curves that are easier to work with, but I think it might be important that they have closed-form solutions to solving the jerk at a given point and velocity on the curve for efficient trajectory planning. The clothoid is easy in this sense, but harder in actually fitting it to the path geometry. B-splines have C2 curvature continuity so jerk could be limited, but I haven't looked into them further yet.

The s-curve generator is coming along well, it seems very fast.
 

Awesome that is what I was trying to understand. from what I've read, having these numbers off can lead to missed steps or no movement. Are there any other issues that would lead one to believe they have these numbers off?

Also, and of course in being curious PNCconf lists the gecko 201 with minimum values listed, in the dropdown choice, if I read the Gecko 201 doc correctly.

Yes, you flash the firmware with mesaflash (make sure you have a recent copy)
pncconf's discovery option will be needed to make the new firmwares encoders
visible.

The source code is there if you want to build you own configurations. Note the the 7I96S uses
an Efinix FPGA chip so needs the Efinity tool chain, not a Xilinx tool chain.

Well, if you would tell us what you are trying to do then we could maybe help.
So, do you want/need to setup the PC with current software or what exactly is not working for you with the system you have got?

Thank you. Shame on me, I thought I had to make the firmware myself. After a day of struggle I found it on mesa store 7i96s page specification -> software. So I just need to flash and try to proceed with pncconf ? HostMot2 is to modify a mesa card firmware and Xilinx studio to create one from scratch for any xilinx card including mesa ones ?

Step time = T3
Step space = T4
Dir setup = T2
Dir hold (missing from chart)

One really important thing to understand is that these are all _MINIMUM_
timings so unless you run into speed limitations, there is no reason to use
minimum values. In fact using minimum values increases the chance of problems

I can make that firmware when I get a chance.

You cannot use the 7I77 enable outputs for direction
as they are hardwired for the  enable function.

Can you give me a list of what is needed?

The fact the mesaflash does not find the 7I76
(and the firmware seems correct) suggests
a hardware issue (either bad 7I92,7I76, or cable)

tommylight wrote:

DAMN that looks like something from "Star Wars" movie !
Probably very old Kuka robot, so
Do you have the control box for it?
Does it have 320 written on the box or hand controller?
What motors does it use?
Does it have encoders or resolvers on the back of the motors?
When did it have the gearbox oil changed?
Does it have a spring or hydraulic counterbalance?
Edit:
Start a new topic for it, if you already did not.
Thank you.

When I saw the robot for the first time, I had the same feeling as you 
I also did some searching to understand the model of the robot and find the DH parameters, but I was not successful, and I think that obtaining the DH parameters of this robot is a challenging task.
As for the controller, luckily there's nothing but a couple of brushless servo motors that I don't think I'll be able to use.
I plan to buy some new servo motors for it
In the case of the controller, I was going to use an EtherCAT servo motor, which I will temporarily use some existing servo motors to reduce the cost.
I have some servo motors with incremental encoders that I will be using.
Also, I have designed a header board using litexcnc to connect to servo motors.
Harmonic gearbox is used in the arms, which I think does not need lubrication.
At the back of the robot is an air jack that supports some of the torque applied to the second link.

So how do you take that info and translate it into Step On-time, step space dir hold and dir setup?

This looks good (I assume you have 2 yellow LEDs lit at the top of the 7I76 board)

That pleases me ;o)
The CR1 LED on the DSUB connector and the CR2 LED on the TB1 connector of the 7I76 card are lit, please see photo

The 7I76 TB1 field voltage should be applied to pins 1 and 8

ok, I have set contact 5 to 1 - the 24V voltage is present
In the meantime, I had also checked the input signals of the three PNP limit switch axle sensors for X, Y and Z and measured the voltage on the 7i76 TB6 contacts 5, 8 and 12 > all LEDs of the sensors do not light up when they are free - then I measure 23.5V at the contacts - when they are above the steel surface, the LEDs do not light up and I measure 0V.

(TB1 pin 5 is only used when W1 is in the right position and VIN is supplied separately)

ok, der Jumper W1 ist links gesteckt

The remaining problems can be either:

This pleases me less :o/
I checked every wire and pin of the ribbon cable between 7i92H and 7i76! Could it be other cables?
Hardware problems with the cards? How can I test this?
LinuxCNC - is there a way to safely update/check this?

mesaflash --device 7i92 --addr 10.10.10.10 --sserial:

cnc@cnc:~$ mesaflash --device 7i92 --addr 10.10.10.10 --sserial
SSLBP port 0:
SSLBP version: 1.43
SSLBP Channels: 4
SSLBP Baud Rate: 2500000

 

Yes