7.1 UMC/EC Pallet Pool Troubleshooting

UMC/EC Pallet Pool - Troubleshooting Guide - NGC

Revision A - 04/2025

Introduction

There are differences between the UMC/EC Pallet Pool and the VMC Pallet Pool, please refer to this troubleshooting guide for issues regarding the UMC/EC Pallet Pool (6/8/10/16/20 Station Pallet Pool options).

This pallet pool option can be installed on the following machine models:

  • UMC-500/SS
  • UMC-750/SS
  • UMC-1000/SS
  • UMC-1250/SS
  • EC-400
  • VC-400

The Next Generation software on the machine must be version 100.20.000.1110or higher.

The Pallet Pool option is not field installable.

The Pallet Pool has 2 servo axes. The PR axis rotates the Pallet Pool saddle and the PS axis extends and retracts the Pallet Pool saddle to load/unload the pallets.

Please refer to the UMC Installation Section or the HMC Installation Section in the Pallet Pool Service Manual for further information on how to install your respective machine. 

Pallet Pool

  1. Emergency Stop 
  2. Pallet Ready Button
  3. Load Station Door
  4. Load Station
  5. Air Gun
  6. Drip Tray

SENSORS

  1. PP Lifter Up
  2. PP Lifter Down
  3. PR Axis Home Switch
 
        4. PP Load Door Open
        5. PP Station Lock

        6. UMC Pallet Slide Home Switch

Note: EC-400 Pallet Slide Home Switch is found underneath the ballscrew.

Symptom Table

Symptom Possible Cause Corrective Action

Alarm 15.108 AXIS SERVO OVERLOAD

Alarm 15.103 AXIS SERVO ERROR TOO LARGE

 Binding Transmission The amplifier could be having an issue driving the motor. If you have this problem, please contact our service department.

After zero returning the PS or PR axis, the following alarms are generated:

Alarm 15.103 AXIS SERVO ERROR TOO LARGE

Alarm 16.103 AXIS SERVO ERROR TOO LARGE

 Faulty Home Sensor Go to the Diagnostics-MOCON tab, search for PR or PS axis home switch inputs. Manually trigger the PR or PS sensors to verify the bits change states from 0 to 1. If the bits do not change states, use the electrical diagram below to determine which component has failed.
Hydraulic oil leaks or sprays from the pallet locating pins during a pallet change.   Contact Haas Service.
Alarm 391  Feature Disabled  is generated commanding M180 & M181 The single switch auto window cannot be commanded independently.

 

Feature must be commanded by the pallet pool template. The customer needs to purchase an auto window install kit to get stand-alone functionality. Refer to AD documents that apply to your machine model.

DC/DT/DM/CM/MM/SMM/UMC-350 - Auto Window - Installation - AD0652

 

UMC Auto Window - Installation - AD0663

 

VMC - Auto Window - Installation - AD0669

 
Alarm 974 Pallet Pool Switch Fault Chips accumulated at sensors. Check the Pallet Lifter Down / Up sensors for chips and clean out any that are found. Recover Pallet Pool and try again. Use the illustrations to locate the sensors.
The pallet pool state proximity sensors are not triggering. Check the Pallet Lifter Down / Up sensor states and make sure the sensors are toggling when triggered. Use the Lifter UP/ Lifter Down I/O Status table below to determine the correct states of the sensor.
Alarm 975 Pallet Pool Lifter Down Time Out Chips accumulated at sensors. Check the Pallet Lifter Down / Up sensors for chips and clean out any that are found. Recover Pallet Pool and try again. Use the illustrations to locate the sensors.
The pallet pool state proximity sensors are not triggering.

Check the Pallet Lifter Down / Up sensor states and make sure the sensors are toggling when triggered. Use the Lifter UP/ Lifter Down I/O Status table below to determine the correct states of the sensor. 

Verify the Pallet Pool Status Cable (P/N 33-0427) is pinned correctly.  Use the Electrical Diagrams below.
Alarm 977 Pallet Pool Lifter Up Time Out Insufficient hydraulic pressure or fluid volume. Make sure the pump is turning on and building enough pressure to lift the Pallet Lifter.
Pallet Lifter was not unclamped. Check for any mechanical obstructions that are preventing the pallet lifter from rising.
Damage to the Pallet Pool up switch or wiring. Check the pallet lifter up and pallet lifter down sensors for proper operation. Use the Lifter UP/ Lifter Down I/O Status table below to determine the correct states of the sensor.
Alarm 9887 Pallet Pool Lifter is Up The Lifter is up when attempting to retrieve a pallet. Enter RECOVERY to attempt auto-recovery, or enter the recovery page to verify that the lifter is operational by commanding it up and down. Check PP Lifter Up (INPUT 38) and verify it is operating correctly. Use the Lifter UP/ Lifter Down I/O Status table below to determine the correct states of the sensor.
Alarm 9888 Pallet Pool Lifter is Down The lifter is down while either retrieving a pallet or placing a pallet. Enter RECOVERY to attempt auto-recovery. If auto-recovery fails, enter the recovery page to verify that the lifter is operational by commanding it up and down. Check  PP Lifter Down (INPUT 41) and verify it is operating correctly. Use the Lifter UP/ Lifter Down I/O Status table below to determine the correct states of the sensor.
Pallet pool is displaying the wrong amount of pallets. Parameter 740 Pallet Pool Max Pallet Count is set incorrectly Change Parameter 740 to the correct pallet count 
Pallet pool up & down solenoid are functioning inversely  Up & down solenoid cables are incorrectly labeled   Order 93-3268 or 93-3268, lower and lift solenoid cable kit for correctly labeled cables. 
Pallet Changer Clamp/Unclamp mechanism operates in reverse. The hydraulic lines are reversed. Check at both ends of the hydraulic lift cylinder and hydraulic power unit and verify that they are set correctly.
The pallet clamp/unclamp sensors are reversed. With a Pallet on the receiver.  Command the pallet to clamp and unclamp.  Go to I/O tab and verify that inputs 25 PALLET CHANGER PALLET UNCLMPED and 29 PALLET CHANGER PALLET CLAMPED toggle to the correct state.  Check the terminal block, check that they are connected correctly.
Alarm 9889 Pallet Pool Slider Door Open Timeout The slider door failed to open within the required time limit Verify there is nothing obstructing the door open switch.
Adjust the flag to the switch and make sure it toggles when in position.
Check to see if the solenoid is functioning properly.
Verify there is nothing obstructing the door open switch.
Alarm 9890 Pallet Pool Slider Door Close Timeout The slider door failed to close within the required time limit
Adjust the switch to the flag and make sure it toggles when in position
Check to see if the solenoid is functioning properly.
Alarm 9892 Pallet Pool Slider Door Not Open  The slider door was detected to be closed when it is expected to be open Check the area around the slider door for obstructions
Verify the correct switch is in the correct location
Alarm 9893 Pallet Pool Slider Door Open  The slider door was detected to be open when it is expected to be closed Check the area around the slider door for obstructions
Verify the correct switch is in the correct location
Pallet "Missing"  message appears on the pallet scheduler page whenever a pallet is loaded in the machine The clamp and unclamp switch are not adjusted correctly  Go to I/O tab and verify that inputs 25 PALLET CHANGER PALLET UNCLMPED, 29 PALLET CHANGER PALLET CLAMPED, and Output  44 PALLET CHANGER UNCLAMPED toggle to the correct state. Adjust the clamp/unclamp switches until they are in the correct state. 
Alarm 946 APC Pallet Clamp Timeout 
Alarm 15.165  PR-Axis Zero Return Margin is Too Small The machine may have shifted during shipping Redo the grid offsets and re-set the tool change offsets. For further instructions contact Haas Service for the internal procedure on how to do so.
Alarm 16.165  PS-Axis Zero Return Margin is Too Small The machine may have shifted during shipping Redo the grid offsets and re-set the tool change offsets. For further instructions contact Haas Service for the internal procedure on how to do so.
Machine is sounding clunky during the majority of the load and pick up cycles The machine may have shifted during shipping The tool change offsets will need to be adjusted. For further instructions contact Haas Service for the internal procedure on how to do so.
"No Pallet" message appears when selecting "Put away Load Station Pallet" and "Get highlighted Pallet" Parameter 2129 was not set to "PP_Shelf_ A" Use the USB Service key to go into Service Mode. Press [DIAGNOSTIC] Go to the PARAMETERS> Factory setting tab. Set the following factory settings value 2129[:] Pallet Loading Shelf = PP_Shelf_A.

For UMC-1250 Machines built before 8/2023:

Pallet's are not sitting flush on the pallet storage stations

 Diameter of the slip fit holes on the pallet is not correct. Refer to the UMC-1250 Pallet Slip Fit Hole Diameter section for further instructions.
Pallets not transitioning smoothly to/from forks to/from storage shelf during pick up and drop off Mechanical misalignment of shelf location  Refer to UMC/EC-PP Fine Adjustment Drop Off and Pick Up section below to fine tune the pallet pool drop off and pick up on your machine.
The machine may have shifted during shipping

Lifter Up/Lifter Down I/O Status

Machine State

PP Lifter Up

Input #38

PP Lifter Down

Input #41

PP Pallet Lift

Output #166

PP Pallet Lower

Output #167
Pallet Pool Lifter is Up 1 0 1 0
Pallet Pool Lifter is Down 0 1 0 1

Load Door I/O Status

Machine State

PP  Load Door Open

Input #31

PP Station Lock

Input #33
Door is closed and the station lock is at the home position 0 1
Door is open and the station lock is at the home position 1 1
Door is closed and the station lock is not at the home position 0 0

UMC-1250 Slip Fit Hole Diameter

Rework the holes labeled [B] and [C] to the size specified in the image.

UMC/EC-PP Fine Adjusting Drop Off and Pick Up

1

If this machine was built before 05/2025, download the latest configuration file for your machine from HBC and update the machine's configuration file.

Note: If the individual shelf parameters were adjusted and a patch file was not created, the configuration update will set the changed values back to the factory settings. 

Note: When performing this procedure, change the dimensioning setting to MM using Setting 9.

2

Use the USB Service key to go into Service Mode.

Enter pallet recovery page and press the letter of the station that needs adjustment then [DELETE] to rotate the pallet pool to the selected station. 

Press [-Z] or  [+Z] to select the Pallet Rotate Axis or Pallet Slide Axis

Use these axes to jog the ram into position to allow for smooth drop off and pick up from the station. 

Test the position by pressing [ALTER] to raise and lower the ram. 

Take note of the  Pallet Rotate Axis position and the Pallet Slide Axis position in the Pallet Pool Status box.

3

Once a desired position is found, exit recovery by pressing [RECOVERY]. 

Press [DIAGNOSTIC] Go to the PARAMETERS> Factory setting tab.

Press [EMERGENCY STOP].

Type in SLIDE and press [F1].

Find the parameter that coincides with the station you are trying to adjust. 

Note:The parameter number for Slide Offset will be between 2130 and 2139, 2306 and 2313, or 2372 and 2379.

Once the parameter is found, type in the noted value for the PS axis and set the new slide offset for the desired station letter using that value.

 

4

Type in ROTARY and press [F1].

Find the parameter that coincides with the station you are trying to adjust.

Note: The parameter number will be between 2140 and 2149, 2314 and 2321, or 2380 and 2387.

Once the parameter is found, type in the noted value from the PR axis and set the new rotary offset for the desired station letter using that value.

Go back to the recovery page and move the pallet pool into a state where you will be able to zero return the PS and PR axes.

Zero Return the PS and PR axis starting with PS.

Once that has been done, test the pick up and drop off of the station. 

Electrical Diagrams

Pallet Pool Input Status and Solenoid Output

                                          

PR/PS Switch and Servo Motor Connection to MainCon PCB

7.2 VMC Pallet Pool Troubleshooting

VMC - Pallet Pool - Troubleshooting Guide

Revision A - 04/2025

Introduction

1

There are differences between the UMC/EC Pallet Pool and the VMC Pallet Pool, please refer to this troubleshooting guide for issues regarding the VMC Pallet Pool machines.

The corresponding pallet pool option can be installed on the following machine models:

  • VF-2YT, VF-2SSYT, VM-2
    • 3 Station Pallet Pool
    • 6 Station Pallet Pool        
  • VF-4, VF-4SS
    • 5 Station Pallet Pool

The Next Generation software on the machine must be version 100.22.000.1010 or higher.

The VMC Pallet Pool option is not field installable.

The Pallet Pool has 2 servo axes. The PR axis rotates the Pallet Pool saddle and the PS axis extends and retracts the Pallet Pool saddle to load/unload the pallets.

Refer to the Pallet Pool - VMC/HMC Installation - Haas Service Manual procedure for details on how to install a VMC pallet pool.

Pallet Pool

  1. Emergency Stop 
  2. Pallet Ready Button
  3. Load Station Doors
  4. Load Station
  5. Air Gun
  6. Drip Tray

Sensors

  1. Receiver Clamp
  2. Receiver Unclamp
 
        3. PP Load Station Door Micro Switches

       4. PP Pallet Slide Home Switch

Symptom Table

Symptom Possible Cause Corrective Action

Alarm 15.108 AXIS SERVO OVERLOAD

Alarm 15.103 AXIS SERVO ERROR TOO LARGE

 Binding Transmission The amplifier could be having an issue driving the motor. If you have this problem, please contact our service department.

After zero returning the PS or PR axis, the following alarms are generated:

Alarm 15.103 AXIS SERVO ERROR TOO LARGE

Alarm 16.103 AXIS SERVO ERROR TOO LARGE

 Faulty Home Sensor Go to the Diagnostics-MOCON tab, search for PR or PS axis home switch inputs. Manually trigger the PR or PS sensors to verify the bits change states from 0 to 1. If the bits do not change states, use the electrical diagram below to determine which component has failed.
Alarm 391  Feature Disabled is generated commanding M180 & M181 The single switch auto window cannot be commanded independently.

Feature must be commanded by the pallet pool template. The customer needs to purchase an auto window install kit to get stand-alone functionality. Refer to AD documents that apply to your machine model.

AD0652 - DT/DM/UMC-350 - Auto Window - Installation

AD0663 - UMC Auto Window - Installation

AD0669 - VMC Small - Auto Window - Installation

 
Pallet pool is displaying the wrong amount of pallets. Parameter 740 Pallet Pool Max Pallet Count is set incorrectly Change Parameter 740 to the correct pallet count 
Alarm 9178 Load Station Inner Door Close Timeout
and
Built before June 2024		 Pallet pool load station inner door didn't close within the required time limit. Verify there is nothing obstructing the door close switch.
Adjust the flag to the prox switch and make sure it toggles when in position.
Check to see if the solenoid is functioning properly.
Alarm 9178 Load Station Inner Door Close Timeout
and
Built June 2024 or later		 Pallet pool load station inner door didn't close within the required time limit. Refer to the Auto Window Troubleshooting Guide for how to adjust and align the new clamp sensors properly.
Alarm 9889 Pallet Pool Slider Door Open Timeout
and
Built before June 2024		 The slider door failed to open within the required time limit Verify there is nothing obstructing the door open switch.
Adjust the flag to the switch and make sure it toggles when in position.
Check to see if the solenoid is functioning properly.
Alarm 9889 Pallet Pool Slider Door Open Timeout
and
Built June 2024 or later		 The slider door failed to open within the required time limit Refer to the Auto Window Troubleshooting Guide for how to adjust and align the new clamp sensors properly
Pallet "Missing"  message appears on the pallet scheduler page whenever a pallet is loaded in the machine The receiver clamp and unclamp switch are not adjusted correctly. Go to I/O tab and verify that inputs 25 PALLET CHANGER PALLET UNCLMPED and 29 PALLET CHANGER PALLET CLAMPED toggle to the correct state. Adjust the clamp/unclamp switches until they are in the correct state. 
Alarm 946 APC Pallet Clamp Timeout 
Alarm 9116 APC Pallet is unclamp The pallet clamp/unclamp inputs are in a invalid state. Go to I/O tab and verify that inputs 25 PALLET CHANGER PALLET UNCLMPED and 29 PALLET CHANGER PALLET CLAMPED toggle to the correct state. Adjust the clamp/unclamp switches until they are in the correct state. 
Alarm 15.165  PR-Axis Zero Return Margin is Too Small The machine may have shifted during shipping Redo the grid offsets and re-set the tool change offsets. For further instructions contact Haas Service for the internal procedure on how to do so.
Alarm 16.165  PS-Axis Zero Return Margin is Too Small The machine may have shifted during shipping Redo the grid offsets and re-set the tool change offsets. For further instructions contact Haas Service for the internal procedure on how to do so.
"No Pallet" message appears when selecting "Put away Load Station Pallet" and "Get highlighted Pallet" Parameter 2129 was not set to "PP_Shelf_ A" Use the USB Service key to go into Service Mode. Press [DIAGNOSTIC] Go to the PARAMETERS> Factory setting tab. Set the following factory settings value 2129[:] Pallet Loading Shelf = PP_Shelf_A.
There is air squeaking out when the receiver is at the top of its stroke. The locating dowel pin is rubbing on the receiver clamp flag. Add grease to the dowel pin to fix this noise.

VF-2YT 3 Station Pallet Pools Built before December 2022

Bolts are too short when replacing the pallet pool trolley plate.

 Longer bolts are now used in the Pallet Pool assembly. Order sixteen (16) of the longer bolts, PN: 40-0011.
The trolley plate is going over the locking pins at one or more pallet shelves and not hooking the pallets correctly. The storage station shelf with this problem will need to be adjusted by its outer leveling foot. Refer to step 2 in the Align Remaining Pallet Shelves section of the Pallet Pool Installation procedure.
VF-2YT 3 Station Install
VF-2YT 6 Station Install
The locating dowel pin fell out of the receiver casting. The receiver camp plate was removed and caused a crash or the casting around the locating pin cracked. The receiver will need to be replaced, refer to the VF - Pallet Pool Receiver Replacement procedure for the kit and instructions on how to replace.
Chips are getting and staying on the bottom of pallets. The machine does not have the window brush kit installed.

Install the window brush kit, refer to the VF-Pallet Pool - Window Brush Retrofit Kit - Installation procedure for the kit and install instructions.

If your application causes more chips than normal utilize the M50P0 wash-program, refer to the M50 Pallet Change Sequence page for more information.
Parts being mis-machined at an angle. Chips are getting stuck under the clamp plate. If your application causes more chips than normal utilize the M50P0 wash-program, refer to the M50 Pallet Change Sequence page for more information.
Inconsistent pallet rotation to each station. The pallet rotate gearbox is loose on its mount. Align pinion gear on gear box to the spur gear. Make sure gear is fully engaged. Tighten down all screws and torque them to spec. Recheck alignment for station load and unload. Refer to VMC-Pallet Pool Installation to align the stations.
Excessive amount of back lash on the pallet rotate.
"Clunk" sound when pallet transitions from saddle to storage stations. Misalignment of PR axis compared to the storage shelf Refer to the VMC-PP Fine Adjusting Drop Off and Pick Up section below for further instruction on how to adjust PR for saddle to station alignment.
Pallet moves forward or backward during hook and  unhook. The storage station is not level or is not at the same height as the saddle Place a long level or straight edge on station rollers and saddle rollers. Adjust the leveling feet for that station until the long level or straight edge contacts with at least 2 rollers the saddle and 2 rollers on the storage station.
Misalignment of PS axis compared to location of locking mechanism and storage shelf Refer to the VMC-PP Fine Adjusting Drop Off and Pick Up section below for further instruction on how to adjust PR for saddle to station alignment.

Load Door I/O Status

Machine State

PP  Load Door Open

Input #31
Both Doors at the Load Station are closed. 0
One or both of the Load Station Doors are opened. 1

VMC-PP Fine Adjusting Drop Off and Pick Up

1

If this machine was built before 05/2025, download the latest configuration file for your machine from HBC and update the machine's configuration file

Note: If the individual shelf parameters were adjusted and a patch file was not created, the configuration update will set the changed values back to the factory settings. 

Note: When performing this procedure, change the dimensioning setting to MM using Setting 9.

2

Adjusting saddle to station alignment:

Use the USB Service key to go into Service Mode.

Enter pallet recovery page and press the letter of the station that needs adjustment then [DELETE] to rotate the pallet pool to the selected station. 

Press [-Z]  or  [+Z] to select the Pallet Rotate Axis or Pallet Slide Axis

Test the transition from the ram to the shelf by jogging the pallet onto the station using PS. If the transition needs adjustment, press [INSERT] to bring the pallet back on to the saddle and adjust the PR in the needed direction and test again till the pallet transition is smooth. 

3

Adjusting saddle to station alignment continued:

Once the PR is adjusted, take note of the Pallet Rotate Axis position in the Pallet Pool Status box and exit the pallet recovery page.

Press [DIAGNOSTIC] and go to the PARAMETERS> Factory setting tab.

Press [EMERGENCY STOP] then type in ROTARY and press [F1].

Find the parameter that coincides with the station you are trying to adjust.

Important: The parameter number will be between 2140 and 2149, 2314 and 2321, or 2380 and 2387.

Once the parameter is found, type in the noted value from the PR axis and set the new rotary offset for the desired station letter using that value.

Go back to the recovery page and move the pallet pool into a state where you will be able to zero return the PS and PR axes.

[ZERO RETURN] the PS and PR axis starting with PS.

Once that has been done, test the pick up and drop off of the station. 

4

Adjusting hook and unhook position:

Use the USB Service key to go into Service Mode.

Enter pallet recovery page and press the letter of the station that needs adjustment then [DELETE] to rotate the pallet pool to the selected station. 

Press [-Z]  or  [+Z] to select the Pallet Rotate Axis or Pallet Slide Axis

Jog the pallet onto the desired station using the PS.

Important: Do NOT travel too far with the PS on to the station. You could run into the bump stop with the pallet and cause an overload alarm or  cause damage to the shelf. 

Once on the station, use the PR to rotate the trolley plate out of the hook of the pallet. Rotate the PS  4 degrees in the negative direction to do so. Check to see if the latch is in the slot on the pallet hook. If the latch is not in the correct spot, move the pallet until it is in the correct location on the station for the latch to engage.

Slowly rotate in the the trolley plate using PR while adjusting the PS to allow for a smooth transition between the trolley plate peg and the pallet hook [1]. Make sure the peg does not pull or push the pallet during the hook motion.

5

Adjusting hook and unhook position continued:

Once the PS is adjusted, take note of the Pallet Slide Axis position in the Pallet Pool Status box and exit the pallet recovery page.

Press [DIAGNOSTIC] and go to the PARAMETERS> Factory setting tab.

Press [EMERGENCY STOP] then type in SLIDE and press [F1].

Find the parameter that coincides with the station you are trying to adjust. 

Note:The parameter number for Slide Offset will be between 2130 and 2139, 2306 and 2313, or 2372 and 2379.

Once the parameter is found, type in the noted value for the PS axis and set the new slide offset for the desired station letter using that value.

Go back to the recovery page and move the pallet pool into a state where you will be able to zero return the PS and PR axes.

Zero Return the PS and PR axis starting with PS.

Once that has been done, test the pick up and drop off of the shelf.

Electrical Diagrams