emergency stop of powerflex 755

[hieutran8969 0]

Dear all, i would like to stop my system in emergency case, it should be stop immediately. my drive is power flex 755 and communicate with PLC control logix via ethernet (port 13). So in control word from PLC to drive, i see a bit is "current limit stop". what does it mean, what kind of stop? can i use it to stop my system (moving item is too heavy, near 200kg)? Thanks in advance,

[Ken Roach 194]

In general, "Emergency Stop" functions remove all power from a drive or motor, causing the load to coast to a stop. Any additional braking would be provided by an external braking system in the case of a typical Emergency Stop. What you are describing is a "Category 1" stop, in which the drive controls the load to a stop and then removes power safely. The "Current Limit Stop" mode on the PowerFlex 755 applies the drive's full rated current toward stopping the load as fast as possible. It's generally selected using a digital input as part of a hardwired safety circuit. This is described in the PowerFlex 750 series Reference Manual in Chapter 1. I cannot advise you on how safety standards are implemented in Vietnam, or how to do use the PowerFlex 755 to do what you need. My recommendation is to test with ordinary ramp-to-stop and then test with the current limit stop and see of the drive can consistently stop your heavy load.