Content
—Mason Radke
—Autosys, LLC
From: Mason Radke <mason@autosysnet.com>
Date: Thursday, January 22, 2026 at 7:32 PM
To: Nichols, Jerry <jenichl@countyofsb.org>, Kevin Seifert <kevin@autosysnet.com>
Subject: Notes for Today 1/22. UF Skid Fixes
PLC Logic Updates, PID Corrections, Communications Improvements, and Alarm Stabilization
Today focused on correcting control logic issues, improving inter-PLC communications, stabilizing pump and blower operation, and resolving several root-cause configuration errors that were impacting production reliability and causing nuisance alarms.
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Completed Work
PLC Communications & Data Handling
* Updated logic in the UF PLC to send a FLOW call to the RDS PLC, which had not been implemented previously.
* Increased message execution rate in the RDS PLC to receive flow and valve status data more frequently from the UF PLC.
* Previous SLC/DH+ communications required slower timing.
* Ethernet-based messaging now supports faster updates reliably.
* Completed unfinished logic to move valve position values into communication tags.
* Updated tags and messaging in the RDS PLC to receive valve position feedback.
* Valve position data may be used in future feed pump lag call logic.
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PID & Control Loop Corrections
* Updated PVs from integer → float for improved resolution and small-signal control on:
* CONV_PID_N115_60 (P35-3)
* CONV_PID_N115_30 (DP loop)
* CONV_PID_N115_150 (DP loop)
* CONV_PID_N145_30 (DP loop)
* Updated CONV_PID_N115_150 to match CONV_PID_N145_150 settings for consistency.
* Updated P35-3 / FIC-3520-3:
* Switched from Dependent → Independent control
* Reduced update time from 0.5s → 0.1s
* Retuned to P: 0, I: 0.01, D: 0
* Monitored trends for overshoot/undershoot
* Updated CONV_PID_N115_30:
* Changed to Independent control
* Updated tuning parameters to match Train 4
* Adjusted minimum setpoint from 0 → -10 to allow the operational -7 setpoint
* Identified and fixed both pressure control loops in production that were configured incorrectly:
* Corrected setpoint minimums so HMI setpoint of -7 could be accepted
* Corrected PID control action direction so loops ramp in the proper direction
* These misconfigurations were causing multiple issues, including high TMP shutdown conditions
* Fix restored correct pressure control behavior and eliminated improper ramping
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Pump, Blower, and Process Logic Improvements
* Increased lag call delay for P3800 feed pumps to allow lead pump ramp-up and flow stabilization.
* Adjusted lag call threshold from 90% → 95% to prevent premature lag pump starts.
* Added interlocks to Blower 85A and 85B to prevent operation when no valves are open.
* Updated Train 3 speed setpoints to match Train 4:
* Production startup: 48%
* Backpulse startup: 35%
* CIP wash startup: 25%
* Updated Train 3 low permeate flow alarm delay from 2s → 10s to match Train 4.
* Updated Train 3 & Train 4 maximum reject flow alarm setpoint from 390 → 450 GPM.
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Chemical System Troubleshooting & Corrections
* Troubleshot CL2 chemical pump fault during maintenance clean:
* Observed brief fault input pulses causing logic faults and routine failures
* Worked with Jerry to test multiple inputs and wiring configurations
* Identified that chemical pump fault relays were wired/configured as normally closed when they should be normally open.
* Reconfigured relays to normally open, corrected associated wiring, and verified logic behavior.
* Tested chemical pump fault inputs after rewiring to confirm proper operation.
* Confirmed no actual pump fault present and restored expected fault handling behavior.
—Mason Radke
—Autosys, LLC