AC Servo Spindle with AASD servo controller stops too abruptly

hello there,
I am not sure wether I am in the right place to ask but we'll see.
I managed to set up a LuxMill Milling machine now with LinuxCNC. Each Axis is driven by a servo Motor, so is the spindle. It's this kind of China AC Servo motors with an AASD series servo drive controller. So far I got everything working except one puzzling bit.
On the 1,8kW servo spindel motor I defined a speed ramp of about 3s to ramp up and down.
However, when I us M5 to stop the spindle then it initially ramps down properly and then at low speeds it sort of jams the brake in and stops very abruptly. Since I am not using an external braking resistor I am afraid that it will throw up an error once I use some tools with more inertia.
Can anyone point me in the right direction where to look? My feeling is that it is one of the many zero speed clamping parameters and not really a LinuxCNc issue.
thanks in advance
Rainer

hi Andy,
thnaks for the suggestion. I am not quite familiar with Linux yet but I'll try your suggestion. Whe I stop the spindle from a higher speed, say 2000rpm then it does not stop immediately but ramps down as it should for a second or two and then somewhere at a lower speet it james the brakes on. That's what I find so irritating.

regards

Rainer

Normally the brake should only switch when the enable signal to the amplifier switches off. This is a backup for hanging axes. Where did you get the servo-on signal from? Is it permanently on or only when you give speed?
Second possibility, change parameters PN029 and PN032 -> 0.
A third idea would be to switch the brake with a relay connected to the machine enable signal.