Yasnac I80 Alarm 3000: Matsuura MAM-600HF Zero Return Recovery

Problem Description

The Matsuura MAM-600HF horizontal machining center equipped with the Yasnac I80 control presents a distinctive commissioning challenge. On initial power-up following long-term shutdown (transport, storage, or parameter-battery loss), the control posts alarm 3000 ("return to zero position each-axis") and refuses to command any axis motion in zero-return, MPG (handle), jog, or rapid modes. The servo amplifiers report no faults. Pneumatic supply, hydraulic pressure, and incoming phase rotation are all verified correct. Tool release and 4th-axis (B-axis pallet changer) clamp/unlock functions still respond from the MDI. This combination of symptoms — saturated reference-required alarm with otherwise healthy subsystems — almost always traces to an ATC interlock condition that has not been satisfied since the last reference-position cycle.

System Architecture

The MAM-600HF pairs a Matsuura 180-tool twin-arm automatic tool changer (ATC) with the Yasnac I80 CNC. Relevant interface points for this fault class:

• Tool matrix cabinet with manual key switch (positions 0, I, AUTO) and per-axis jog toggles
• Dual-arm robot gantry with two-axis servo drive and rotary tool pot
• Parameter battery-backed SRAM (five lithium cells on the parameter PCB)
• Three alarm screens on the CRT/MDI (active, history, PMC)
• LED diagnostic display on the tool matrix side cabinet
• Door interlock chain using M-codes M111 (closed) / M112 (open)

The Yasnac I80 enforces ATC interlocks through parameter bitfields. Parameter 7090 is the principal ATC interlock control word on the MAM-600HF ladder: bit 0 enables interlock-neglect (service mode), bit 3 enables manual jog of the robot from the matrix, and bit 4 enables the ATC maintenance display on the CRT.

Alarm 3000 Definition

Alarm 3000 on the Yasnac I80 is a power-up reference-position reminder. It is generated whenever the control loses absolute machine position, which occurs on battery replacement, parameter initialization, encoder battery failure, first commissioning, or extended power-down. The alarm itself is not a fault — only an indication that the reference position has not been re-established for one or more axes. The alarm is designed to clear automatically after a successful zero-return (the I80 equivalent of G28) of every controlled axis.

What is unusual in this failure mode is that the zero-return command itself is suppressed by an external interlock. The alarm cannot be cleared by the documented reference-return procedure until the inhibiting condition is removed.

Root Cause Analysis

A systematic isolation sequence is required. With the only active alarm being 3000 and no servo drive faults, the controller is software-ready but mechanically inhibited. The most probable causes in descending order, based on field experience with this platform:

1. ATC robot parked on a travel limit. The dual-arm carrier cannot complete its home routine because one of its forward, rear, or rotational limits is engaged. The Yasnac I80 will not allow full-axis zero return until the ATC completes its own reference cycle.
2. Tool pot rotation fault. The robot tool pot is not at the orientation the controller expects for the empty-pot handshake.
3. Spindle tool-presence mismatch. The control believes a tool is loaded in the spindle or robot when none is physically present.
4. Tool matrix door interlock. The M111/M112 state does not match the door limit switches.
5. Parameter battery loss. Five internal cells back the Yasnac I80 SRAM. Loss of any cell can corrupt the ATC coordinate table.

The first physical action on any MAM-600HF that will not zero return is to verify the ATC robot is not parked against a limit switch.

Pre-Diagnostic Checks

Before opening the parameter tree, verify each of the following independently. Each check resolves a different class of fault and must be eliminated before proceeding.

ATC Robot Position Verification

Power off the machine. Open the ATC enclosure and physically inspect the dual-arm robot. The tool pot should be fully retracted into the gantry, not against the forward or rear travel limit. If the robot is on a limit:

1. Confirm main power is off and locked out.
2. Push the robot off the limit by hand. The robot carrier rides on linear rails and can be moved with moderate force once power is removed.
3. Inspect the transfer gantry pivots. A failed pivot bearing can stop the robot short of its fully retracted position, leaving it resting on the rear limit. This is a common field observation on machines with high tool-change cycle counts.
4. Restore power and re-attempt zero return before proceeding to parameter changes.

ATC Recovery Procedure

This procedure clears the ATC interlock state and places the robot in the manual load position. Execute the sequence exactly as shown. Each step is required.

Step 1 — Enable Parameter Write

1. Press the [RUN] key on the MDI panel.
2. Press the [SETTING] soft key (top-right of the CRT).
3. Press the next [SETTING] soft key to page forward.
4. Select PARAMETER EXCHANGE from the menu.
5. Press [WR] (write) — parameter write is now enabled.

The WR LED on the MDI panel will illuminate, confirming write access. If the LED does not light, any subsequent parameter change will be silently rejected.

Step 2 — Activate ATC Troubleshooting Mode

1. Press the [MAINT] key.
2. Type 7090 on the keypad.
3. Press cursor-down [v] to move the cursor into the bit field of the displayed value.
4. Press right-arrow [>] to position the cursor under bit 4.
5. Press [WR] to toggle bit 4 from 0 to 1.
6. Repeat the cursor move to bit 3 in the same row, then press [WR] to set bit 3 to 1.

Parameter 7090 bits 3 and 4 must both be set to 1. Bit 4 enables the ATC maintenance display on the CRT; bit 3 enables manual jog of the robot via the matrix-side toggle switches. Verify the bit display on the CRT before continuing.

Step 3 — Lock Parameter Write

1. Press the [RUN] key.
2. Press [WR] to toggle parameter write off.

This prevents inadvertent modification of other parameters during the manual recovery sequence.

Step 4 — Manual Robot Positioning

At the tool matrix side cabinet:

1. Turn the key switch to position I (manual operation). This disconnects the matrix controller from automatic commands.
2. Locate the jog toggle switches. Two are typically provided: one for radial arm travel and one for tool pot rotation.
3. Use the toggles to drive the robot to the load position — the point at which a tool would be manually inserted into the robot pot for a manual tool change.

Load position reference dimensions (measured from the machined base that the tool racks mount to):

• 500 mm to the bottom of the key on the face of the robot tool pot
• 82.5 mm from the outer diameter of the robot tool pot to the formed channel that holds the proximity sensor

These dimensions are approximate. The proximity sensor (empty-pot detect) must align with the channel for the matrix controller to recognize the load position. If the empty-pot sensor has failed, the matrix controller will not auto-retract on key return — see verification below.

Step 5 — Verify Auto-Retract

Turn the key switch from I back to position 0. The robot should retract smoothly back into the gantry under servo power.

• If the robot retracts automatically: the ATC interlock is satisfied. Proceed to parameter restoration.
• If the indicator light stays green and the robot does not retract: the load position was not correctly located. Re-jog and recheck the 500 mm / 82.5 mm dimensions. The empty-pot sensor may also need to be manually simulated if the proximity switch has failed.
• If an LED alarm appears on the matrix display or on the main CNC: record the code and consult the matrix alarm table before continuing.

Step 6 — Restore Normal Parameters

1. Repeat the parameter write-enable sequence from Step 1.
2. Press [MAINT] and type 7090.
3. Clear bit 3 to 0 (cursor, then [WR]).
4. Clear bit 4 to 0 (cursor, then [WR]).
5. Press [RUN], then [WR] to disable parameter write.

The ATC is now in normal mode and the robot is in its retracted reference position.

Zero Return Procedure

With the ATC interlock cleared, perform the standard reference return:

1. Select Zero Return mode on the MDI ([REF] or the equivalent soft key, depending on I80 screen layout).
2. Select each axis in turn.
3. Command motion in the + direction using the axis-select switch and the + jog button.
4. Each axis should rapid toward its reference marker, decelerate on the marker, and settle on the reference position with the position counter reading zero.

Repeat for X, Y, Z, and the 4th axis (B-axis pallet changer on the MAM-600HF). After all axes complete zero return, alarm 3000 should clear automatically and the control should enter the Ready state.

Interlock Neglect (Emergency Workaround)

If normal zero return is still blocked after ATC recovery, the controller is being held off by an interlock whose source has not been identified (ladder discrepancy, undocumented wiring change, or failed sensor). Parameter 7090 bit 0 enables interlock neglect and allows axis motion despite the unknown interlock. This is a commissioning tool, not a production setting.

1. Parameter write-enable (as in Step 1 above).
2. Press [MAINT], type 7090.
3. Set bit 0 to 1.
4. Lock parameter write.
5. Execute zero return on all axes.
6. After alarm 3000 clears, set bit 0 back to 0.
7. Lock parameter write.

Yasnac I80 ATC Parameter Reference

M-Code Reference

These codes force the door state in the controller logic and are useful when verifying door interlock integrity during commissioning. They do not physically actuate the door hardware.

Cleared-Tool Recovery

If the control believes a tool is in the robot or spindle but none is physically present, the matrix offers two recovery paths:

1. Trans arm unclamp switch. A manual switch on the matrix cabinet that releases the spindle gripper without commanding motion. Use this if a tool is physically clamped in the spindle but the control thinks the spindle is empty.
2. Clear button. Clears the controller's tool-in-spindle and tool-in-robot memory. If the CLEAR button is rejected, power-cycle the machine and try again. A common field observation: a single CLEAR attempt immediately after power-up fails because the ladder has not fully initialized, but a second attempt after a 60-second wait succeeds.

Alarm #2 "Kept Tool" can appear if the controller refuses to release its tool-memory state. Power-cycle + CLEAR is the standard recovery. If the alarm is persistent across multiple cycles, the issue is likely in the spindle-orientation sensor or the tool-pot-present proximity switch, not in the controller memory.

Battery Maintenance

The Yasnac I80 uses five internal lithium cells (typically BR-2/3A or equivalent) to back parameter SRAM. Symptoms of battery failure:

• Parameter values reverting to defaults on power-up
• Tool table data corruption or loss
• Position counter loss even with encoders powered
• ATC coordinate table reset, forcing full re-initialization

Replacement Procedure

1. Power on the machine. SRAM must remain powered during the swap.
2. Locate the battery holder on the parameter PCB (rear of the CNC cabinet, typically labelled BAT or BT1–BT5).
3. Replace one cell at a time, observing polarity.
4. Verify parameter 0 and tool table integrity after each cell swap.
5. If all five batteries have been removed for transport, the machine will require full re-initialization including the ATC recovery sequence above.

Immediately after battery replacement, dump the parameter set to RS-232 or memory card using the Yasnac I/O utility. Verify the parameter file size and checksum on the host side. See the Yasnac I80 parameter manual for the exact transfer protocol.

Ladder Documentation Caveat

A common field issue on used MAM-600HF machines is ladder documentation mismatch. Matsuura shipped multiple ladder revisions over the production run, and a documentation set from a different serial number can lead directly to misdiagnosis. If the on-machine ladder does not match the printed set:

• Verify the machine serial number plate (typically on the operator-side column).
• Order the matching manual set from Matsuura. Field quotes for serial-number-specific documentation run in the USD 450 range with lead time measured in weeks if the manuals must be sourced from Japan.
• Cross-check critical interlock chains against the actual field wiring rather than relying on the print.

Recovery State Diagram

Verification Checklist

After zero return and parameter restoration, confirm the following before releasing the machine to production:

• Alarm 3000 cleared from all three alarm screens
• No servo drive alarms on any amplifier
• X, Y, Z, and 4th axis all at reference position with position counter reading zero
• ATC robot retracted, tool pot at home rotation
• Tool change cycle executes without alarm
• M111/M112 door commands execute and report correct state
• Parameter 7090 bits 0, 3, and 4 all cleared (back to 0)
• Parameter write disabled (WR LED off)
• Tool table memory intact (load a known tool, recall by number)
• One full automatic tool change cycle complete (e.g., T01 → T02 → T01) without alarm
• Spindle orientation command (M19) executes at correct angle
• Coolant, chip conveyor, and pallet changer functions respond to MDI

Troubleshooting Matrix

Safety and LOTO Notes

• Lock out / tag out the main disconnect before manually moving the robot or reaching into the ATC enclosure.
• Hydraulic pressure must be bled before removing any actuator in the tool-change circuit.
• The Yasnac I80 retains stored energy in the parameter PCB for several minutes after power-down. Wait at least five minutes before handling the parameter PCB or its batteries.
• Do not run the ATC in automatic mode with parameter 7090.0 set. The interlock-neglect bit disables safety chains that protect the operator and the machine.
• Verify the spindle is empty and the robot pot is empty before any manual tool-change operation.

FAQ