PSL HWPの動作不良

Fujimoto-san, YamaT-san, Ikeda

Fujimoto-sanからPSLのHWPが回転していないため、IMCのロックが復帰しないと連絡があり復帰させた。

[調査]
調査したところ、2026-08-15 20:04:11 JSTにGuardianからPSLのHWPを回転させた際、制御PCからk1scriptへのコールバックを行い移動後の位置が更新されるはずが、値が更新されずにHWPが動作中と判定が残っていた。
(K-Log#36869でも似た現象があったが、今回はPermissionは正常で別の原因です。)

YamaT-sanの調査によると、同時期にEPICS gatewayが一時的に死んでいた。
そのため、k1scriptからEPICSチャンネルへの書き込みに失敗してしまっていた。
EPICS Gatewayは30分程度で復帰していたが、HWPは自動復帰できないため、手動でコールバックを行い復帰させた。

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PSL HWP Operational Issue

Fujimoto-san, YamaT-san, Ikeda

Fujimoto-san reported that the IMC lock could not be restored because the PSL HWP was not rotating. The issue has now been resolved.

Investigation

At 20:04:11 JST on August 15, 2026, Guardian issued a command to rotate the PSL HWP. After the movement, the control PC was expected to send a callback to `k1script` to update the HWP position. However, the value was not updated, leaving the system in a state where the HWP was still considered to be in motion.
A similar issue occurred in K-Log #36869. However, the permissions were configured correctly this time, so the root cause was different.
According to YamaT-san’s investigation, the EPICS Gateway was temporarily unavailable at around the same time. Consequently, `k1script` failed to write to the EPICS channel.
Although the EPICS Gateway recovered after approximately 30 minutes, the HWP could not recover automatically. We therefore triggered the callback manually and restored the system.