Content
# Troubleshoot centrifuge sludge pumps
Chris says the sludge pump is not turning off when the centrifuge goes into shutdown on alarm. The pumps are controlled fine otherwise.
Rung from the centrifuge PLC that controls the sludge pumps:
![[Troubleshoot_centrifuge_sludge_pumps_image_2.png]]
sludge pump stops on either Level 1 alarm or Pause
Pause is caused by:
pause pb
sludge pump A or B keypad stop
WW Flush timer timing
Level 2 alarm
pumps are being controlled by I/O on the drives from wiring, not from SCADA/PLC. There is an AOI for the pumps and they are all setup to run from SCADA via ethernet to the drives, just need to configure the drives to start/stop from ethernet.
After talking to Chris more it appears that the centrifuge shut down without triggering a Level 1 alarm, although they do not know what alarm was triggerd. They have also had a couple "phantom" alarms that cause a shutdown but don't show on the alarm screen on the centrifuge hmi.
The grinder and polymer sytems were not called to stop either , which leads me to believe that the PLC did not call for the sludge pumps, grinder, or polymer to stop, and therefore this is not an issue with the sludge pump controls.
Looking in the centrifuge program to see what triggers an AutoStop.
![[Troubleshoot_centrifuge_sludge_pumps_image_3.png]]
sludge pumps auto_start on polymer system running indication.
**a Level 1 alarm does not trigger an auto_stop, it stops the auto_stop. is this right?
polymer skid will go into polymer_auto_stop when the auto_stop_in_progress is 1
looking for something that would cause the scroll and bowl to shutdown but not the polymer or grinder
checking alarm indications on hmi match plcLow Relative Speed is listed as a Level 2 but is a Level 1 in plcfound some level 1 alarms that are not on the HMI:OIL LUBE FAULTOIL LUBE HIGH PRESSUREOIL LUBE DE LO FLOWOIL LUBE FE LO FLOWFE OIL LUBE HI RTNDE OIL LUBE HI RTNThe oil feed logic is not called in the PLC
haven't found anything. it maybe possible that the scroll drive was slowing down to compesate for a higher torque.