Traub TX8: Troubleshooting Alarms 027 and A01 Safely

Direct answer: On this Traub TX8, alarms 027 Not Aus Numerik and A01 Not Aus Maschine point first to an open or unreliable emergency-stop circuit, not automatically to an axis sitting on a hardware limit switch. The axes were reported mechanically clear, with approximately 200 mm of available travel in both directions, so inspect the emergency-stop devices, their wiring, and connector P5 in the operator panel before attempting axis recovery.

Interpret the Two Alarms Together

The simultaneous messages identify two related layers of the shutdown:

Displayed alarm	Diagnostic meaning	First checks
027 Not Aus Numerik	The numerical-control side is in an emergency-stop state.	Check whether the machine-level emergency-stop chain is preventing the control from receiving its permissive.
A01 Not Aus Maschine	The machine emergency-stop condition is active.	Inspect emergency-stop contacts, field wiring, and the operator-panel connection.

The drive refusing to switch on is an expected consequence while the emergency-stop chain remains open. Repeated drive-enable attempts will not clear the condition; the control must first receive a valid machine safety permissive.

The shutdown occurred shortly after parameters were reinstalled from punched tape and the axes moved briefly. That timing makes the restored parameter set relevant, but it does not prove that a parameter caused the alarms. A stuck contact, damaged cable, or disturbed panel connector can produce the same result and can be checked without changing the restored data.

Separate Axis-Limit Problems from the Emergency-Stop Chain

Do not decide that the X-axis is on a hardware limit merely because it stopped near the chuck. Visual position is not a reliable indication of limit-switch state. A limit input depends on the switch actuator, wiring, input circuit, and machine geometry rather than the apparent position alone.

In this installation, removing the side cover showed that the axes were mechanically free and that approximately 200 mm of travel remained in both the positive and negative directions. That observation makes a physically overtraveled axis unlikely. It does not, however, test whether a limit-switch contact or input is electrically stuck.

Use this decision path:

1. Confirm mechanical clearance without commanding motion.
2. Check the control diagnostics, electrical drawings, or input indication for the limit-switch state if those resources are available.
3. If an axis is physically on an emergency overtravel switch, recover it mechanically using the machine's hand crank accessory and the approved machine procedure.
4. If the axes are clear, stop treating axis position as the primary fault and troubleshoot the emergency-stop chain.

Do not crank an axis merely to clear 027 or A01 when no overtravel has been confirmed. Unnecessary manual motion near the chuck can create a collision without repairing the open safety circuit.

Run the Emergency-Stop Diagnostic Sequence

Work from the field devices toward the control. Isolate power before opening the operator panel or testing wiring, and use the machine schematic to preserve the intended safety-channel arrangement.

1. Release every emergency-stop operator fully. Rotate or pull each device as required by its mechanism, then verify that it mechanically latches and resets cleanly.
2. Inspect each emergency-stop contact block. A contact can remain mechanically stuck or electrically closed/open even when the button appears released.
3. Test the emergency-stop contacts with an appropriate meter while the circuit is isolated. Compare the measured state with the contact designation in the electrical drawing.
4. Inspect cables between the emergency-stop devices and the control cabinet. Look for broken conductors, loose terminals, pinched cable sections, and intermittent connections at moving or hinged panels.
5. Check connector P5 inside the operator panel for correct seating and reliable contact.
6. Restore power only after covers, connectors, and safety devices are returned to their operating condition. Attempt the prescribed safety reset, then check whether both alarms clear.

If the alarm changes while an emergency-stop device, cable, or operator-panel harness is moved, treat that as an intermittent fault rather than a successful reset. Locate and repair the defective contact or conductor before returning the machine to service.

Inspect Operator-Panel Connector P5

Connector P5 is a specific inspection point for this symptom. A loose or oxidized connection in the operator panel can interrupt the emergency-stop signal and make the control report a machine and numerical-control emergency stop even when all external buttons appear released.

1. Remove machine power according to the site's isolation procedure.
2. Open the hinged operator panel without pulling on its harness.
3. Identify P5 from the machine documentation or panel marking; do not infer connector identity from position alone.
4. Check that the plug is fully seated and retained.
5. Inspect the plug and receptacle for displaced pins, contamination, corrosion, damaged locking hardware, or conductors pulling out of their terminations.
6. Reseat the connector only if the machine documentation and connector condition allow it, then secure the panel before applying power.

Reseating P5 is a diagnostic action, not proof of repair. Afterward, operate each emergency-stop device individually and verify that the machine enters and exits the safety state predictably.

Recover an Axis Only After Confirming Overtravel

If electrical diagnostics confirm that an axis is holding an emergency overtravel input, the stated recovery method is to move the affected axis manually with the machine's accessory hand crank. Because the drive cannot be enabled during the emergency-stop condition, manual recovery moves the mechanism off the actuated switch without relying on powered motion.

1. Identify the affected axis and required recovery direction from the switch state, machine geometry, and electrical documentation.
2. Check the tool, chuck, workholding, and adjacent axes for collision risk.
3. Isolate energy and install the correct hand crank at the designated mechanism.
4. Move only far enough to release the confirmed overtravel switch.
5. Remove the crank and restore all guards before resetting the machine.
6. Verify the switch input changes state and that the axis position is plausible before enabling further motion.

If the axis has substantial clear travel in both directions, return to the emergency-stop circuit checks instead of forcing manual movement.

Verify the Repair and Avoid Repeat Faults

A cleared display alone is insufficient. Complete a functional check before permitting automatic motion:

1. Confirm that 027 Not Aus Numerik and A01 Not Aus Maschine remain cleared after reset.
2. Verify the drive can be enabled normally.
3. Test each emergency-stop operator separately and confirm that it removes the drive permissive and produces the expected shutdown.
4. Reset each device and confirm that restart requires the machine's normal reset sequence; releasing a button alone must not initiate motion.
5. Jog the axes cautiously while monitoring direction and remaining mechanical clearance.
6. Retain the restored parameter record and compare it with the correct record for the exact machine type and machine number before normal production use.

Recurring pitfalls include bypassing a safety contact to obtain drive enable, assuming a new buffer battery validates the parameter set, diagnosing overtravel solely from visual axis position, and treating a temporarily successful connector reseat as a permanent repair. If these checks do not isolate the fault, record the exact machine type, machine number, displayed alarms, and measured safety-input states for manufacturer-qualified support.

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