Hello colleagues, I am new to this and I have had this problem for several months now. I will explain the situation. I have a MAZAK 410 A NEXUS control 640 M CNC. Unfortunately, about 6 months ago the NC battery ran out and all the parameters were lost. I did the process of resetting the HR 113 card. I have the manuals and I have already loaded the parameters again, identical to how they are in the book. I modified some to convert from inches to millimeters, soft limit (minor changes) and in general, it already turns on and has no alarms. It has taken me quite a while. Apparently everything works now, but when I start to work the Z axis starts to go down as if it had no power or a parameter was wrong. We also set the parameters of the servo motors with respect to the book by means of privileged mode 1131, that is, apparently the parameters of the servo motors are already correct. What we have no idea about are the letter "O" parameters, what they are for, nor do we have what parameters it should have. We do not know if this has to do with our failure or is causing us to fail. We need to modify some parameter in servo motors or some other field. We appreciate your help from someone since we are stuck with this problem. Greetings, have a nice day. Sincerely, Marcus