Need Siemens 840D Help

[gears2010]

Issue with a gear cutting machine with a siemens control, erratic issue with machine going into a feed hold condition with no alarms present. Machine may run for one day or one hour and then fault in the middle of cycle(spindle stays running). Message on control states, wait:feedrate enable missing and program has stopped. All axis's show enabled but there is no movement and no drive faults are present. Axis's will move manually in jog but the machine will not reference or position in any other mode. No programming issues and there is not any signs of drift (control loop issues). NC/PLC archives have also been reloaded. After power down/up or nck reset it is impossible to ref. (no movement) no alarms. Any suggestions would be appreciated.

[gaswiz69]

Without knowing the machine and how the machine builder wired all the systems, it would be difficult at best to try and troubleshoot your problem. That being said, start by looking at any and all sensors relating to interlocks, be it door, spindle speed, tool change. I would think the control is "waiting" or looking for a condition to be met. Without a listing of the electric diagram or even the input output addresses, this would be very difficult to determine.

[erdinct]

yes it waiting a think

[F.Sharifi]

daer sir
i have seen many time this problem , this is just Spindle / feed stop signal missing ! it is not like Optional stop ,..all control system manufacturer uses this signal for safty module mabe in the begining may be in the last line ,..in Heidenhain you find it as FEED LOCK ,..in Siemens and Philips is the same ,..it is uses for machine safty ,...

that means , in your machine somthing happen in safty system ,..such as doors ,..lubrication level or pressure ,..lock back your machine and just try to find somethings like for sure

[802DSpecialist]

Go into the Diagnostics area and see if all enables are present. There is probably something in the PLC holding up the machine or a loose wire on the enables.