Alarming News! Five Machine Alarms You May Not Know About

What happens when an alarm goes off on your machine tool? It may be a routine fix or alert you to something more complex. Our top five alarms are not the most frequently occurring, but they’re important to know in case one appears on your machine tool. Discover some of the alarms you may see on your Okuma machine tool, why they occur, and how to prevent them from occurring as frequently in the future.

1151 MCS INVERTER UNIT DETECTED AN ERROR

This alarm usually indicates an issue with an inverter, whether a defective inverter control board, motor over current, low or high voltage, or a shorted motor. There have been occasions when a motor will take out a drive unit and both will need to be replaced. In one case, we replaced the inverter, MCS power supply, and servo controller. In the end, the issue turned out to be a damaged encoder cable at the motor. Problems like this can be very elusive, and sometimes expensive for our customers. In these cases, our Okuma Support Center members will create ad-hoc solutions based on our troubleshooting experiences. These solutions are then saved as knowledge base articles for future reference.

721 DEVICE NET ERROR

This alarm can occur after an option has been added to the machine tool or new software has been installed into the OSP control. Causes of this alarm include poor electrical connections, incorrect switch settings, or I/O mapping that may not have the necessary IO's mapped for the newly installed option. This alarm is more frequently seen on the GENOS lathe products after option installation. The GENOS lathe software incorporates an additional DVD that contains the I/O mapping software. Therefore, forgetting to install this additional DVD can definitely cause the 721 alarm to occur.

758 SAFETY I/O ERROR

This alarm occurs when a problem has developed in the safety IO link. Common causes of this alarm include a shorted solenoid or a switch that has been exposed to coolant contamination and has shorted out. Damage may happen to an IO board when this happens. The code that follows this alarm in most cases will point the repair technician to the proper input or output location, but in some cases, it can be difficult to identify the slot or connector number. If so, in-depth troubleshooting is necessary.

812 ERROR DURING INITIALIZATION OF MCS

This alarm indicates that during control boot-up, the OSP control sees a discrepancy in the serial link of the MCS system. The cause could be a faulty drive unit, improper controller ID address setting, or an issue with the servo cabling connections. This alarm could also stem from prior troubleshooting that was administered and miswiring occurring in the serial link of the MCS system.

4085 FAN MOTOR ERROR ON PANEL COMPUTER UNIT

This indicates the CPU fan or the power supply fan are not operating at the specified threshold speed set by the control. A technician can visually inspect the fan to see if it is plugged in correctly and properly rotating. If the fan is rotating slowly, this requires replacement of the fan, but if the fan looks to be rotating at the correct speed, the panel computer would need to be inspected to find the root cause.

Troubleshooting these types of alarms often requires a technician with proper training and knowledge of the OSP control and associated electrical systems. Fortunately, the Okuma Support Center maintains a library of knowledge and experience-based articles which are created from real-life troubleshooting scenarios based on these alarm conditions.

Special thanks to Brian O’Dell, Support Center Tech, Okuma America Corporation, for providing this article.