The SMP main control panel and remote control module were updated in order to implement the following items which were deemed desirable during commissioning:
- 24 VDC line added to E-stop circuit:
Previously the E-stop relay cut power to only 120 VAC. This means that the lid rotation motor would stop instantly, but since the lid open/close valve is powered by 24 VDC which comes from a power supply unit, there would be a short delay while the unit powers off in which the valve was still active. This could result in a situation in which, for example, someone is operating the pendant to close the lid and another person recognizes a hazard and presses the E-stop on the main panel, but the lid does not stop closing for approximately 3 seconds while the operator is still holding the "close" button down.
To rectify this issue, the 24 VDC line was routed through a NO contact of the same E-stop relay that controls the entire 120 VAC supply to the system. This was tested on Oct. 25, 2019 - working.
- Status feedback signals to remote control room:
Previously status signals for "Lid raised", "Lid Centred", "CW Limit", and "CCW Limit" were only displayed as light indicators on the main control panel. It was determined during remote operation that it would be helpful to have these signals sent back to the software interface so that an operator does not need to use a camera to look at the light indicators.
Electrical drawings and cable schedule have been updated to reflect these changes. The SMP will be tested again using the commissioning plan checklist to confirm no there were no inadvertent effects on the rest of the same from these changes.
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