PLC 23 DUAL MEDIA FILTERS 5 AND 6 SCADA SYSTEM OPERATION MANUAL. Revision 1.0 April 18, 2006

Transcription

1 PLC 23 DUAL MEDIA FILTERS 5 AND 6 SCADA SYSTEM OPERATION MANUAL Revision 1.0 April 18, 2006

2 PLC 23 DUAL MEDIA FILTERS 5 AND 6 SCADA SYSTEM OPERATION MANUAL Revision 1.0 April 18, 2006 Table of Contents 1 Introduction Revision History PLC System Overview Conventions Set Points and Process Values Equipment Colors Line sizes and colors Instrument Bubbles New Control Strategies PLC 23 Filters 5 and Filter Control Backwash Cycle Shared Backwash Systems Filtered Water Pump Station Sample SCADA Screens Dual Media Filters Overview Dual Media Filter Dual Media Filter Controls Dual Media Filter Valves Open / Close Valve Backwash Set Points Filtered Water Pump Station Filtered Water PS Set Points Filtered Water Pump Staging April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 1

3 7 Sample Panel View (OIT) Screens Dual Media Filter Dual Media Filter Controls Dual Media Filter Valves Open / Close Valve Backwash System Backwash Set Points Filtered Water Pump Station Filtered Water PS Set Points Filtered Water Pump Staging April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 2

4 PLC 23 DUAL MEDIA FILTERS 5 AND 6 SCADA SYSTEM OPERATION MANUAL Revision 1.0 April 18, Introduction This document presents the operational logic and sample SCADA screens for the Dual Media Filters 5 & 6 and the Filtered Water Pump Station at the Tertiary Treatment Plant of the Stockton Regional Wastewater Control Facility. 2 Revision History The table below shows the history of revisions to this document. Rev. Description By Date 1.0 Issued for customer training Max Hanson/ April 18, 2006 Imran Saeed 3 PLC System Overview Dual Media Filters 5 & 6 operation is controlled by a PLC (programmable logic controller), which is identified as PLC23. A touch-screen Operator Interface Terminal (OIT) is connected to one of the PLC Ethernet channels (CH1), for allowing the plant operator to monitor and control the filters process locally. This PLC is also communicating to the plant main SCADA system fiber optic Ethernet network, through its second Ethernet channel (CH2). Process instrumentation such as pressure, level and flow transmitters and control signals for VFDs and valves are wired to the I/O and communication channels of the PLC. The PLC monitors the process values from its analogue and digital input channels. When the control mode is in AUTO, the PLC determines the necessary control outputs for achieving the desired process conditions according to the process set points entered by the operator. In Manual mode the plant operator can control the process by manually entering the values through OIT. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 3

5 PLC24 operation is further explained by the block diagram below (Fig-1). PLC23 Filters 5 & 6 Controller (Allen Bradley Control Logix PLC) OIT (Operator Interface Terminal) CPU (Control Logic Processing) Ethernet Network Communication. CH1 Ethernet Network Communication. CH2 Digital I/O Channels Analogue I/O Channels Ethernet (RJ45) Ethernet (RJ45) ETHERNET Switch Ethernet (RJ45) Ethernet (RJ45) ETHERNET Switch Ethernet (RJ45) I/O Control Valves, PIT, FIT, TIT, LIT, etc. FC Fiber/Copper Converter FC Fiber/Copper Converter Fiber optic Fiber optic I/O FC Ethernet (RJ45) Fiber/Copper Converter FC Ethernet (RJ45) Fiber/Copper Converter Switches, Open/Close commands, etc. Variable Speed Drives Plant Central SCADA Fig-1; PLC-23 Operation Block Diagram April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 4

6 4 Conventions 4.1 Set Points and Process Values Set points appear with a black background inset field and white text. Process values will show an inset field with a white background and blue text. Status indicators also have the white inset field, but the foreground color may change depending upon the conditions and the background will turn yellow for abnormal situations. Status Indicator Text Colors: Text Background Meaning Dark Red White Not called, inactive, off Dark Green White Called, active, on Gray White Not ready, unavailable for PLC control Black Yellow Alarm, abnormal condition 4.2 Equipment Colors Symbols for motor-driven equipment are animated with colors to reflect status. Valves symbols are also color-coded. Foreground Red Green Gray Yellow Foreground Red Green Gray Yellow Meaning Not called, inactive, off Called, active, on Not ready, unavailable for PLC control Alarm, abnormal condition Meaning Closed Opened (or called to open if no feedback) Position is uncertain or mid travel Alarm, abnormal condition 4.3 Line sizes and colors Where appropriate, major process lines are shown with 3D pipe symbols and are animated to show when fluid is flowing. Minor process lines are shown with a dark gray background and an animated foreground color. Minor process lines do not have 3D appearance and are smaller. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 5

7 Foreground Gray Blue Cyan Yellow Light Green Magenta Pink Light Brown Teal White Dark Brown Meaning No flow is present Plant water Miscellaneous minor process (e.g., scrubbant) Sulfur dioxide Chlorine or sodium hypochlorite Ferric Chloride Polymer Wastewater Storm water Air Sludge 4.4 Instrument Bubbles Many screens will be arranged to show process flow similar to a Process and Instrumentation Diagram (P&ID). Instrument bubbles will show tag names and will have the relevant process value displayed. These bubbles are animated and will turn yellow when an alarm is present at the instrument represented by the bubble. Clicking on the instrument bubble will open the appropriate pop-up screen (note that these symbols are not used for some existing instruments as the PLC logic does not include all the features necessary to support the pop up screen). Note also that bubble type symbols are reserved for transmitters, which have a host of alarm set points associated with them. Discrete devices (e.g., pressure switches) that simply generate a single alarm will trigger a visible alarm indicator when tripped, but do not have a bubble that is visible all the time. 5 New Control Strategies 5.1 PLC 23 Filters 5 and 6 PLC 23 is a new PLC that will control two new dual media filters and the Filtered Water Pump Station Filter Control Each filter consists of two filter cells (A and B), which share a gullet that connects to the applied water (influent) and backwash drain channels. Each filter cell is serviced by an air scour inlet valve, a backwash supply valve and an effluent flow control (modulating) valve. The pair of cells shares an applied water gate, a backwash drain gate and an effluent isolation valve. In the discussion below, loop numbers of the form 50-xZy should be interpreted as follows: April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 6

8 x = filter number (5 or 6) Z = process number, will be enumerated in text y = 1 for cell A and 2 for cell B Turbidity Measurement A turbidimeter, tag number AIT-50-x1y, will measure the effluent turbidity for each cell. The PLC will receive this measurement in the form of a 4-20mA signal. High-high, high, low and low-low alarms are provided with adjustable set points. A transmitter fail alarm is posted when the signal is out of range. All these alarms have a common delay set point. A common selector disables all alarms for the instrument Flow Measurement A magnetic flow meter, FIT-50-x2y, will measure the effluent flow rate from each filter cell. The PLC will receive this measurement in the form of a 4-20mA signal. High-high, high, low and low-low alarms are provided with adjustable set points. The low and low-low alarms will only be enabled when a filter is online. A transmitter fail alarm is posted when the signal is out of range. All these alarms have a common delay set point. A common selector disables all alarms for the instrument. A resettable flow total is calculated by the PLC in millions of gallons Headloss Measurement A differential pressure transmitter, PDIT-50-x4y, will measure the headloss across each filter cell. The PLC will receive this level in the form of a 4-20mA signal. High-high, high, low and low-low alarms are provided with adjustable set points. A transmitter fail alarm is posted when the signal is out of range. All these alarms have a common delay set point. A common disable selector disables all alarms for the instrument Level Measurement An ultrasonic level transmitter, LIT-50-x5y, will measure the level in each filter cell. The PLC will receive this level in the form of a 4-20mA signal. High-high, high, low and low-low alarms are provided with adjustable set points. A transmitter fail alarm is posted when the signal is out of range. All these alarms have a common delay set point. A common disable selector disables all alarms for the instrument Valve Control Each valve may be manually controlled from the SCADA or local operator interface Operating Modes MANUAL The valve opens and closes in response to pushbuttons. For modulating valves, the position command can be adjusted directly. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 7

9 AUTOMATIC The valve opens and closes in response to filter backwash and service modes. The modulating valve positions are controlled by flow controllers Monitoring The following status points are monitored and displayed on the operator interface. REMOTE Local/Remote switch is set for remote (PLC) control. READY Valve is ready for PLC control (in remote and not failed) FAIL The valve did not respond to an open or close command for a delay period. POSITION Opened, Closed or Middle according to limit switch signals. Modulating valves will also have a position transmitter. CALLED Called to open or called to close. COMMAND Modulating valves have a position command in % rather than discrete open and close calls Automatic Backwash Trigger There are several conditions that can indicate when a filter requires backwashing. When the process value for one cell has exceeded the set point, the backwash trigger condition has been met. Each automatic backwash trigger can be individually enabled or disabled. TURBIDITY When the effluent turbidity from either cell is above a high turbidity set point for a delay period and the filter is online a backwash will be triggered if enabled. HEADLOSS When the headloss across the filter bed for either cell is above a high headloss set point for a delay period and the filter is online a backwash will be triggered if enabled. VOLUME The PLC tracks the volume treated since the last backwash for each cell. When one cell exceeds the volume trigger set point and the filter is online a backwash will be triggered if enabled. RUNTIME The PLC tracks the runtime since the last backwash for each cell. When one cell exceeds the time trigger set point and the filter is online a backwash will be triggered if enabled. Only one of the six filters may backwash at a time. If a backwash is required but another filter is already in backwash, this filter will continue operation until it is permitted to enter backwash mode. Hardwired interlocks are used to interface with the existing filter controllers Manual Controls Online or offline state is controlled by a manual pushbutton. Once a filter has been turned on, it may be manually backwashed by clicking on a start backwash button. When backwash is in progress, an operator may abort the wash cycle by clicking on an abort button. If a particular step needs to be extended, an operator may click the step hold button. This will hold the backwash cycle at the current step until the hold button is April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 8

10 clicked again, releasing the sequence. If an operator needs to skip a step, he or she may click the step advance button, advancing the sequence by one step for each mouse click. The step advance button will also clear the step hold state Backwash Cycle The table below describes the backwash sequence. Step numbers are used in program documentation and are interpreted as follows: the most significant digit indicates major BW step, the middle digit delineates the minor BW step and the least significant digit indicates the cell. The transition column describes the conditions necessary to exit from the step. Notes follow the table. No. Step Actions Transition Note 100 Initiation Close AW Gate x01 Open Isolation Valve x10 AW Gate x01 is closed and Isolation Valve x10 is open BW Surge Tank Level below start set point BW Lagoon Level below start set point 111 Drawdown Effluent Flow Control Valves x31 and x32 to 100% Level in cell below set point or maximum A 112 open duration exceeded 121 Close Set Effluent Flow Control Valve x31 or x32 to 0% Valves are closed A 122 Effluent Valve open 130 Isolate Filter Close Isolation Valve x10 Valve is closed 211 Initiate Air Open BW Drain Gate x02 Gate is opened Scour 221 Blower Start Air Scour Blower Blower is running, valve is called After 10 sec, open Blower Discharge Valve 231 Start Air Open Cell A Air Scour Valve x71 Valve is Opened Scour A 241 Air Scour A Air Scour for time duration Elapsed time >= Desired 232 Start Air Open Cell B Air Scour Valve x72 Valve is Opened B Scour B 251 End Scour A Close Cell A Air Scour Valve x71 Valve is Closed B 261 Scour A Pause before BW Elapsed time >= Desired end of Air Scour Pause Pause 242 Air Scour B Air Scour for time duration Elapsed time >= Desired B April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 9

11 No. Step Actions Transition Note 252 End Scour B Close Air Scour Valve x72 Valve is closed B 262 Stop Blower Close Blower Discharge Valve Blower is off B Scour B Pause After 10 sec, stop Blower Elapsed time >= Desired end of Air Scour Pause 310 Close ST Close Surge Tank Drain Valve is closed B Drain 311 Slow BW A Open Cell A BW Supply, x61 Start BW Pump 1 Set BW Target = Slow BW set point Valve is opened BW Pump 1 is running Cell level above set point Or elapsed time >= Desired Both BW pumps on Blower off 411 Prepare Fast BW A Start BW Pump 2 Set BW Target = Fast BW set point B 421 Start Fast Allow flow to increase 30 Second Delay before BW timer starts B BW A 431 Fast BW A BW for desired duration Elapsed time >= Desired B 511 End BW A Open Cell B BW Supply Valve opened Set BW Target = 2 x Slow BW set point 312 Slow BW B Slow BW through both cells Valve opened Cell level above set point or Elapsed time >= Desired 412 Prepare Fast Set BW Target = Fast BW set point 5 second Delay BW B 422 Start Fast Close Cell A BW Supply, x61 Valve closed BW B 432 Fast BW B BW for desired duration Elapsed time >= Desired 512 End BW B Close Cell B BW Supply, x62 Stop BW Pump 1 Stop BW Pump 2 BW Flow Target = 0 After 15 sec, open Surge Tank Drain BW Pumps Off 522 Close Waste Close BW Drain Gate, x02 Gate is closed 530 BW Set Clean Status B April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 10

12 No. Step Actions Transition Note Complete If Filter is selected for Online, return to service, otherwise leave in Offline Clean State Notes: A B C Draw down is simultaneous for both cells. When the level for a cell is below the end draw down set point, the effluent flow control valve for that cell closes. Drawdown is complete when both effluent flow control valves are closed. Air Scour of Cell B is simultaneous with slow BW of cell A. If the Air Scour duration is long enough, Air Scour of cell B may also overlap with fast BW of cell A. Air scour of cell B must be complete before slow BW of cell B can commence. A backwash will abort if the entire sequence takes longer than a maximum duration. It will also abort if a piece of equipment (valve, gate, pump or blower) fails to operate when called to do so. If the level in the filter goes above a backwash maximum set point or below a backwash minimum set point during the backwash sequence, this will also cause the cycle to abort Shared Backwash Systems Several systems are shared between all six filters. Since each of the existing filters has a separate controller, this requires a hardwired interlocking system. The backwash control panel uses relays and signal isolators to allow the existing controllers and (when modified) the new PLC to control and monitor the following devices. Device Discrete Monitor Discrete Control Analog Monitor Analog Control BW Pump 1 Running Call to Run BW Pump 1 Valve Opened Limit Switch Closed Limit Switch Call to Open Call to Close BW Pump 2 Running Call to Run BW Pump 2 Valve Opened Limit Switch Closed Limit Switch Call to Open Call to Close BW Flow Control Flow Rate Control Valve Position Surge Tank Level Surge Tank Drain Valve Opened Limit Switch Closed Limit Switch Call to Open Call to Close Backwash Lagoon Level Air Scour Blower Running Call to Run April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 11

13 5.1.4 Filtered Water Pump Station The filtered water pump station includes three pumps and a wetwell. The pumps lift filtered water up into the chlorine contact channel Level Measurement An ultrasonic level transmitter, LIT , will measure the level in the wetwell. The PLC will receive this level in the form of a 4-20mA signal. High-high, high, low and low-low alarms are provided with adjustable set points. A transmitter fail alarm is posted when the signal is out of range. All these alarms have a common delay set point. A common disable selector disables all alarms for the instrument Pump Control The operator selects the schedule for the pumps. The schedule arrangement is similar to that used for off-site lift stations. The operator may select a role of LEAD, LAG1, LAG2, or ROTATE for each pump. Two pumps may be set to rotate roles while one is fixed. Pumps that are set to rotate roles will automatically take roles that have not been assigned. The roles will rotate when the lead pump s runtime since the last rotation exceeds an adjustable set point. If a pump becomes unavailable because it has failed or is in local mode, other pumps set to rotate roles will promote to fill any gaps in the schedule Operating Modes MANUAL The pump starts and stops in response to pushbuttons. Speed may be set from the operator interface. AUTOMATIC The pump starts and stops in response to wetwell level. Speed is controlled by the level control loop Monitoring The following status points are monitored and displayed on the operator interface. REMOTE VFD is set for remote (PLC) control rather than local keypad control. READY Pump is ready for PLC control (in remote and not failed) FAULT VFD is reporting a fault condition. FAIL Either a fault has been present for a delay time or the VFD did not return a running status after being called for a delay period. RUNNING Motor is running. CALLED VFD is called to run by the PLC. SPEED COMMAND The speed requested by the PLC (%). SPEED Actual speed at which the VFD is operating (%). CURRENT Current output of the VFD to the motor (Amps). RUNTIME Reported in tenths of an hour. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 12

14 6 Sample SCADA Screens Sample screens for PLC 23 follow. These are the screens that will appear on the plant SCADA system. Screens with similar function and design are configured on the local Panelview operator interface and are shown in section 7 of this document. Please note that no process data was present when these screens were generated. This means that process values will show zero and it is operating scenarios that are not actually possible may be shown. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 13

15 6.1 Dual Media Filters Overview This screen shows a plan view of the dual media filters and gives summary status information. Clicking on a filter will open a detailed screen. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 14

16 6.2 Dual Media Filter This is an example of a detailed filter screen. It shows a stylized section view of the filters looking south toward the applied water and backwash drain channels. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 15

17 6.3 Dual Media Filter Controls This pop up window gives an operator access to the controls for a filter. It includes automatic backwash triggers and pushbutton controls. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 16

18 6.4 Dual Media Filter Valves The valve summary window shows status information for all the valves and gates. Clicking on one of the status boxes will open the pop up window for that valve or gate. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 17

19 6.5 Open / Close Valve This is an example of a valve pop up for a motor operated valve with limit switches. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 18

20 6.6 Backwash Set Points This screen allows an operator to edit the set points that control transitions between steps of the backwash sequence. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 19

21 6.7 Filtered Water Pump Station This screen shows the status of the filtered water pumps. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 20

22 6.8 Filtered Water PS Set Points The filtered water pumps are controlled by wetwell level. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 21

23 6.9 Filtered Water Pump Staging This screen allows an operator to enter the desired schedule for pump operation. the chlorine feed rate. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 22

24 7 Sample Panel View (OIT) Screens Sample screens for local Panel view operator interface for the Wetlands Pump Station follow. The function of these screens is exactly similar to the SCADA screens explained above in section 6. These are the screens that will appear at the plant Operator Interface Terminal (OIT) of odor control system. Please note that no process data is present in these screens and these were generated during the offline development. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 23

25 7.1 Dual Media Filter This is an example of a detailed filter screen. It shows a stylized section view of the filters looking south toward the applied water and backwash drain channels. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 24

26 7.2 Dual Media Filter Controls This process window gives an operator access to the controls for a filter. It includes automatic backwash triggers and pushbutton controls. Clicking on one of the Filter X Controls button will open this window. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 25

27 7.3 Dual Media Filter Valves The valve summary window shows status information for all the valves and gates. Clicking on one of the Filter X Valves button will open this window for that valve or gate. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 26

28 7.4 Open / Close Valve This is an example of a valve pop up for a motor operated valve with limit switches. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 27

29 7.5 Backwash System This screen shows the backwash system status. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 28

30 7.6 Backwash Set Points This screen allows an operator to edit the set points that control transitions between steps of the backwash sequence. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 29

31 7.7 Filtered Water Pump Station This screen shows the status of the filtered water pumps. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 30

32 7.8 Filtered Water PS Set Points The filtered water pumps are controlled by wetwell level. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 31

33 7.9 Filtered Water Pump Staging This screen allows an operator to enter the desired schedule for pump operation. April 18, 2006 Rev. 1.0 PLC 23 Dual Media Filters 5 and 6 SCADA System Operation Manual Page 32