No Motion Allowed (NMA) state
Refer to a description of the No Motion Allowed (NMA) state and a list of recommended operator actions in an NMA scenario.
The NMA state is a condition set as a result of an accessor that detected an apparent obstruction to normal accessor movement. An obstruction can be detected in either X or Y motion. Unexpected motion of the pivot motor and unexpected activation of the cartridge present sensor are the detection mechanisms.
- The accessor collides with an obstacle in the accessor aisle, such as a cartridge that is sticking out of a cell. Other possible causes include debris in the lower X-rail gear rack such as a screw, piece of plastic, or other debris that would interfere with accessor motion.
- A cartridge is only partially in the gripper.
- The accessor detects a false obstruction.
When the NMA detection capability is set to ON and an accessor encounters an apparent obstruction, the library is placed into the protective NMA state. Error message 48A0 displays on the TS4500 management GUI. If SNMP traps are enabled, a trap is also generated and sent. When the library goes into the NMA state, all motion immediately stops on the affected accessor. The NMA state protects the library from further damage as a result of a detected obstruction.
When the NMA detection capability is set to OFF, motion continues even after the accessor detects an apparent obstruction. However, if the cartridge present sensor is activated when the accessor moves, or if the gripper is not clear, the library is put into the NMA state. When the NMA detection capability is set to OFF, and accessor motion is allowed to continue despite an obstruction, there is a risk of damage to the library and storage cells.
It is recommended that the NMA detection capability is set to ON. Your IBM® service representative can set this detection capability.
Customer recovery procedures in an NMA state
If the library goes into an NMA state, you can open a library door to check for and remove any obvious obstructions, such as a cartridge partially sticking out of a cell. If no obstructions are found, the accessor might have falsely sensed an obstruction. The action of opening the door resets the NMA state and allows the library to continue operations when the door is closed.
If no obvious obstructions are found, the problem might be related to other causes, which your IBM service representative can determine. If the root cause is not corrected, the library might again enter an NMA state, which generates a Call Home.