LAST UPDATED: 05/20/2019

Pneumatic Safety Door Interlocks Troubleshooting Guide

Introduction

Symptom Table

Symptom Possible Cause Corrective Action

Sensor is misaligned Check the sensor alignment

No power to the solenoid or the sensor Measure the voltage at the I/O PCB

Piston is stuck from contamination Clean the piston assembly

Alarm 223 DOOR LOCK FAILURE

Broken return spring Replace the broken spring

In the image, the cover for the sensor and pistonis removed.

1. Proximity sensor2. Piston3. Stop block

Note: The door shown closes to the right. Onmachines with two doors, the sensor and stopblock for the left door are on the left side of thepiston.

Pneumatic Safety Door Interlocks Troubleshooting Guide

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Alignment

Corrective Action:

If the door was removed or any components areloose, the door interlock sensor can becomemisaligned. Inspect the door rollers and makesure all of the interlock components are aligned.

• R is 0.0" - 0.09" (0.0 - 2.3 mm). Space R isthe distance between the end of theproximity sensor housing [2] and thetop of the stop block [3].

• S is 0.06" - 0.25" (1.5 - 6.4 mm). Space Sis the distance between the extendedpiston [1] and the stop block [3].

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Voltage

Corrective Action:

Interlock solenoids use the power-to-lock system.

Command a spindle speed of 100 rpm.

Measure the voltage at the I/O PCB. The correctvoltage is 120 VAC. Verify that voltage is present(connectors P29 [1] on a Classic Haas Control(CHC), P40 and P41 [2] on a Next GenerationControl (NGC)) when the door is closed andlocked. If no voltage is present, go to I/O PCB -TROUBLESHOOTING GUIDE (CLASSIC HAASCONTROL) to troubleshoot the I/O PCB. If voltageis present, test the solenoid. Refer to SOLENOID -TROUBLESHOOTING GUIDE to troubleshoot thesolenoid.

Set the pendant key to “run”/locked mode. Closethe door. Make sure the sensor indicator lights[4,5] activate. If the sensor lights fail to activate,the sensor may be defective, misaligned, or havea faulty connection. Refer to Sections 1and PROXIMITY SENSOR - TROUBLESHOOTINGGUIDE to troubleshoot the proximity sensors.

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Contamination

Broken Spring

Improper maintenance of the machines airsupply can lead to water contamination andFailure of the machines door interlocks.

If the interlock is contamintated, make sure themachine air supply is clean and dry.

Rebuild the intelock per the steps below

Corrective Action:

Remove the upper fitting and O-ring (59-1997) [1]and the piston assembly [2] from the interlockbody [3]. Use a pick to remove the bottom o-ring[7].

Clean the inside of the interlock body and allparts. Replace any damaged o-rings.

Apply a thin coat of silicone grease to the Pistono-ring (59-2218) [4], the piston shaft [5], thespring [6], and the bottom o-ring (59-2218) [7].

Fix the source of contamination to prevent arecurrence of the problem.

Corrective Action:

Remove the upper fitting and O-ring (59-1997) [1]and the piston assembly [2] from the interlockbody [3]. Use a pick to remove the bottom o-ring[7].

Clean the inside of the interlock body and allparts. Inspect/replace the spring [6], 59-1409.

Apply a thin coat of silicone grease to the pistono-ring (59-2218) [4], the piston shaft [5], thespring [6], and the bottom o-ring (59-2218) [7].

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Electrical Diagram

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