What the TeachComm alarm means

The controller loses communication with the WMS pendant; the screen freezes or the pendant reboots, and teaching/jogging becomes impossible. We fix this Staubli CS8 / CS9 (VAL3) fault almost daily, and one round of on-site checks usually confirms what is going on.

Most common causes

  • Damaged pendant cable or connector
  • 24 V instability affecting the pendant link
  • Pendant hardware failure
  • Controller pendant-port fault
Field note: We have tallied real cases: the first cause tops the list, so start your diagnosis there.

Step-by-step field fix

  1. Reseat and inspect the pendant cable and connector
  2. Swap-test with a known-good pendant
  3. Check the 24 V rail stability
  4. Power-cycle the controller
  5. Replace the pendant or repair the port based on the swap result
Safety first: For Staubli teachcomm, when communication drops, controller and external devices can disagree about state; at reconnect, external axes or tooling may act on stale commands. The self-serviceable action is Reseat and inspect the pendant cable and connector; anything past that falls under external axes and tooling interlocks and needs a certified engineer.

How we diagnose communication alarms on site

Staubli teachcomm belongs to the communication family. On Staubli teachcomm the failing stage is CS8 / CS9 - the data link: fieldbus, Ethernet, cabinet-to-body communication and external device interfaces. We start reading Staubli teachcomm at the pendant error list and VAL3 log, with cabinet module indicators.

The chain involved in Staubli teachcomm runs: physical layer (cable / connector / shield) -> link layer (protocol / baud / node ID) -> application layer (data mapping / handshakes).

On Staubli teachcomm we start at the physical layer by default: Communication alarms start at the physical layer by default, not in parameters. The reason is simple: most field communication faults are cable and connector faults - oxidised pins, unlanded shields, broken cores in the drag chain, missing or wrong termination resistors. A meter and your eyes find these cheaply and they hit often. Only with the physical layer proven do we move to node IDs, baud rates and data mapping; the reverse order burns hours and ends at a loose connector.

Field notes on this page cover Staubli teachcomm (Teach Pendant (WMS) Communication Lost); written by the Henghuan repair team, updated 2026-10-01.

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Related Communication alarms

Fieldbus33 — Internal Error on Fieldbus Board — Status 33
Same family: this code belongs to the Communication alarms family - the page collects all Communication-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for Epson · Nachi · Omron and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the Staubli teachcomm alarm mean?

The controller loses communication with the WMS pendant; the screen freezes or the pendant reboots, and teaching/jogging becomes impossible. We fix this Staubli CS8 / CS9 (VAL3) fault almost daily, and one round of on-site checks usually confirms what is going on. Staubli teachcomm sits in the communication family; on our work orders the highest-frequency trigger for this code is "Damaged pendant cable or connector".

QCan I clear a Staubli teachcomm alarm myself?

Whether Staubli teachcomm clears on its own depends on the outcome of "Reseat and inspect the pendant cable and connector". Finish the flow with "Replace the pendant or repair the port based on the swap result" to confirm Staubli teachcomm - do not skip it. If that step is clean, the second most frequent cause on Staubli teachcomm is "24 V instability affecting the pendant link". When Staubli teachcomm keeps coming back it is not a one-off trigger - especially if Replace the pendant or repair the port based on the swap result is where you get stuck. Do not keep producing through Staubli teachcomm.

QFor communication alarms like Staubli teachcomm, how long does a site visit take?

The commonest causes we see on Staubli teachcomm are "Damaged pendant cable or connector, 24 V instability affecting the pendant link, Pendant hardware failure", so we stock the van against those. For Staubli teachcomm specifically, we carry common bus cables, connectors, termination resistors and shield terminals. For Staubli teachcomm, communication work is about tracing the physical link segment by segment; most cases close in one visit. Before we roll, tell us what Staubli teachcomm shows on the pendant error list and VAL3 log, with cabinet module indicators and what the machine was doing - phone or video triage is free.

This page on Staubli teachcomm is based on the field experience of the Henghuan Robotics repair team. Alarm explanations are our own summary for troubleshooting reference and may differ across controller and software versions — if unsure, verify against Staubli documentation or reach out to us. Henghuan is an independent service provider with no affiliation or endorsement by Staubli.