Yes, that is correct. Problem is, both for M211 and M210. The "Release all brakes" code is M212, which is probably given when you press unlock.
Try to verify wether it's M210 or M211 that is the problem, they require opposite solutions. Try putting it into C axis mode and then in MDI run M211. Jog the C axis around a bit, how does it behave? Then try M210, you can't jog it in this mode but you can see how it behaves.
When M210 clamp command is given, a timer of a couple of seconds start to count down. When it is done the C axis power is drastically reduced. This is probably to stop the C axis from fighting a solidly clamped spindle. This is why I think M211 is the problem, the C axis should not have enough power to jerk in M210.
Also, M211 is the one that always act like this in any C axis lathe, so the odds are it's this one this time too.
Long story short:
If it's jerking in M210, the brake is not grabbing enough and need MORE friction.
If it's jerky in M211, the brake is too grabby and needs LESS friction.
Curious, what kind of integrex? And what parameter have you been instructed to change?
I follow. Not on the DROOP thing though, I'm completely lost as for what you are talking about there.
I did a quick check today.. and I found it difficult to connect the issue to one specific 'mode'.
The operator was finished with his workpiece and had taken it out, the machine was in M210 mode when I got there. It hade not done any C(Y) axis interpolation as the part just had some holes. It was vibrating but with very low frequency (this can be low or very high depending on.. something).
So I did M212, again all vibration was gone. I put it then in M210, no vibration. However a small pulsation could be felt when putting my hand on the chuck.
Then I did M212 and then M211. Initially, just the same pulses could be felt, however after joging it around a bit, the vibrations came back and could clearly be felt when touching the chuck. But it seemed to turn smoothly, I could not feel any jerkiness when touching the spindle while rotating. The vibrations seemed to primarily be felt when idle. As to what initiated them is another thing of course.
I know for a fact though that it is vibrating while in M210 sometimes though, perhaps M211 can start it and then M210 can escalate it.
The machine is a E410II machine.
I looked up the parameter, and a description of what the root of the problem is in a word document on the computer. The operator who has written it probably did not understand the technician completely as I find the description awkward. But here it is:
"The reason for the vibrations is that the C-axis overcompensates the goal value which causes the rotation of the axis to be bad"
"In order to correct it do as follows:
Type: 1131 and then Input
Scroll to Parameter: SP71 and go to column SPDL 2. The setting range here is 1-999, although values over 500 is not recommended"
Thomas: - "I put in value 70 here and it seemed to work"
Thomas: "now I had to change it to 300 which seems to work "