I am using a reTerminal DM with injection molding machine and facing unstable capacitive touch behavior.
Symptoms:
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Screen randomly zooms in/out
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Touch position shifts
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Touch becomes stable only when I physically touch the reTerminal chassis with my hand
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Issue appears when powered from Mean Well mdr-60-24 power supply.
This suggests a grounding or common-mode noise issue affecting the capacitive touch controller.
Power setup
Power supply used:
Mean Well MDR-60-24 (DIN-rail SMPS)
Connections made:
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L/N connected to machine single-phase supply
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+24 V / −24 V connected to reTerminal DM
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V− bonded to panel PE
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reTerminal chassis bonded to panel PE
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MDR-60-24 FG bonded to panel PE
Despite these connections, issue persists.
Measurements
Measured AC voltage between:
MDR-60-24 V− and panel PE ≈ 60 V AC (before grounding changes)
After bonding FG and V− to PE, behavior improved slightly but touchscreen instability still remains.
Touch becomes stable immediately when:
I touch chassis with my hand
which suggests missing reference stabilization or high common-mode noise in cabinet environment.
Machine environment
Installation is inside an injection molding machine panel containing:
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hydraulic motor contactors
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possible VFD drives
Cable length between PSU and reTerminal is short (<2 m).
Tests already performed
Tested:
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bonding V− to PE
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bonding FG to PE
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bonding chassis to PE
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verifying continuity of panel earth
Questions
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Is reTerminal DM known to require isolated supply in industrial control panels?
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Does Seeed recommend grounding output negative to PE or keeping it floating?
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Are there any official EMC mitigation guidelines for capacitive touch stability in noisy cabinets?
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Has anyone successfully deployed reTerminal DM with injection molding or CNC panels without isolated DC-DC stage?