PLC 24 FERRIC CHLORIDE AND POLYMER SYSTEM SCADA SYSTEM OPERATION MANUAL. Revision 1.0 May 3, 2006

Transcription

1 PLC 24 FERRIC CHLORIDE AND POLYMER SYSTEM SCADA SYSTEM OPERATION MANUAL Revision 1.0 May 3, 2006

2 PLC 24 FERRIC CHLORIDE AND POLYMER SYSTEM SCADA SYSTEM OPERATION MANUAL Revision 1.0 May 3, 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 Control Strategies General Motor Control Ready to Start Motor Failure Alarm Restart Delay Sequential Start Delay Runtime Monitoring Ferric Chloride Pump Control (P12-401, P12-402) Speed Control Alarms and Interlocks Ferric Chloride Area Alarms (LSH , FSH ) Polymer Tote Weight Monitoring (WIT , WIT ) Alarms and Interlocks Polymer Blend Unit (M13-301, M13-302) Polymer Dose Control... 9 May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 2 of 25

3 5.5.2 Alarms and Interlocks Polymer Injection Valves (FV , 402, 403, 404) Alarms and Interlocks Sample SCADA Screens Ferric Chloride Overview Ferric Chloride Pump Control Pop-up Ferric Chloride Set points Primary Polymer System Overview Primary Polymer Blend Unit Pop-up Primary Polymer Valve Control Pop-up Primary Polymer Set points Sample Panel View (OIT) Screens Ferric Chloride Overview Ferric Chloride Pump Control Pop-up Ferric Chloride Set points Primary Polymer System Overview Primary Polymer Blend Unit Control Pop-up Primary Polymer Valve Control Pop-up Primary Polymer Set points May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 3 of 25

4 PLC 24 FERRIC CHLORIDE AND POLYMER SYSTEM SCADA SYSTEM OPERATION MANUAL Revision 1.0 May 3, Introduction This document presents the operational logic and sample SCADA and OIT (local operator interface terminal) screens for the Ferric Chloride and Polymer System at 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/ May 3, 2006 Imran Saeed 3 PLC System Overview PLC24 control the operation of the odor control, ferric chloride and the primary polymer systems as shown in the Fig-1 below. A touch-screen Operator Interface Terminal (OIT) is connected to one of the Ethernet channels (CH1) on the main PLC rack, for allowing the plant operator to monitor and control the process locally and the same Ethernet channel (CH1) is also communicating to RIO24 (remote I/O rack) over the fiber optic cable. 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 digital and analog I/O channels of the PLC. The PLC monitors the process values from its analog 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. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 4 of 25

5 PLC24 operation is further explained with the help of the block diagram below (Fig-1). RIO 24 Odor Control System (Allen Bradley Control Logix Remote I/O Rack) Ethernet Network Communication. CH1 Digital I/O Channels Ethernet (RJ45) Analog I/O Channels OIT (Operator Interface Terminal) PLC24 Ferric Chloride & Polymer System /Odor Control System (Allen Bradley Control Logix Main PLC Rack) CPU (Control Logic Processing) Ethernet Network Communication. CH1 Ethernet Network Communication. CH2 Digital I/O Channels Analog I/O Channels FC Fiber/Copper Converter Ethernet (RJ45) Ethernet (RJ45) Ethernet (RJ45) FC Fiber/Copper Converter ETHERNET Switch Fiber optic Ethernet (RJ45) FC Fiber/Copper Converter FC Fiber/Copper Converter Ethernet (RJ45) Fiber optic Plant Central SCADA Fig-1; PLC-24 Operation Block Diagram May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 5 of 25

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) Not ready, unavailable for PLC control 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. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 6 of 25

7 Foreground Gray Blue Cyan Yellow Light Green Magenta Pink Light Brown Teal White Meaning No flow is present Plant water Miscellaneous minor process (e.g., scrubbant) Sulfur dioxide Chlorine or sodium hypochlorite Ferric Chloride Polymer Sludge Storm or wastewater Air 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 (an example for a ph transmitter is shown below). 5 Control Strategies The odor control PLC (PLC24) controls the ferric chloride and polymer injection through its remote I/O rack (RIO24). Both of these chemical feed processes use flow pacing to control the dose. 5.1 General Motor Control The following control strategies apply to all motors controlled by the PLC Ready to Start A motor is considered ready when it is available for the PLC control. For the PLC to start the motor the following conditions must be met: (1) the Off-On-Remote switch must be in the Remote position, (2) the motor must not have an active failure alarm Motor Failure Alarm A failure alarm is posted when the PLC calls a motor to run and does not receive running confirmation within an adjustable time delay or when the PLC receives a fault input for the same time delay. Upon a failure, the PLC will de-energize the motor call output and the motor will be considered unavailable. The failure alarm will latch until an operator resets the alarm on the local operator interface or from the SCADA system. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 7 of 25

8 5.1.3 Restart Delay Each motor is equipped with a timer so that the PLC will not call it to run until it has been off for an adjustable time delay. This is intended to allow the motor to rest and allow for any backspin that may be necessary for some pumps or fans. Typically, motor restart delay set points are global to a particular process or PLC Sequential Start Delay A sequential start delay is used to prevent simultaneous starting of many motors. This adjustable delay period will be imposed between motor starts Runtime Monitoring Elapsed run time is tracked for each motor. This value is recorded in hours (and fractions of hours) and can be reset by the operator. 5.2 Ferric Chloride Pump Control (P12-401, P12-402) Two modes of operation are available at the Operator Interface Terminal (OIT) or SCADA system. MANUAL AUTO In manual control the pump will start and stop in response to pushbuttons on the operator interface or SCADA screens. In manual mode, pump speed will be manually controlled by set point entry. In automatic mode, the pump will run continuously. Speed will be determined by the speed control algorithm described below Speed Control When the pump is in automatic, its speed is controlled by flow pacing. A desired chemical flow rate is calculated from the following equation: Desired Flow Rate in gpm = D x Q 1440 x C x SG In this equation, D is the desired dose rate entered by the operator in mg/l. Q is the plant flow rate in MGD. C is the (operator adjustable) concentration of the chemical solution in % and SG is the (operator adjustable) specific gravity. Speed output for the pumps is calculated from the desired chemical flow by interpolati11on from a 5-point calibration table that is accessible on the local OIT. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 8 of 25

9 5.2.2 Alarms and Interlocks A failure alarm will stop the PLC from calling the pump to run. If alarms are disabled for a pump, its output will be held on even if no running confirmation is received. Each pump is equipped with a high discharge pressure switch. If this switch is triggered for an adjustable time delay a high pressure alarm will be posted. A high pressure alarm will latch until reset and will stop operation of the associated pump. 5.3 Ferric Chloride Area Alarms (LSH , FSH ) The ferric chloride area generates two miscellaneous alarms. If the level in the sump within the containment area reaches the high level switch, an alarm will be posted. If the safety shower / eyewash in the ferric chloride area is used it will be detected by a flow switch and an alarm will be triggered. 5.4 Polymer Tote Weight Monitoring (WIT , WIT ) The weight in the polymer totes is monitored to warn when supply is running low Alarms and Interlocks The weight will trigger high high and high alarms when over the respective set points. It will also trigger low and low low alarms when below these set points. A common alarm delay is used for all of these alarms. An operator may disable all alarms for this instrument if it is malfunctioning or undergoing maintenance. If a low low weight alarm exists for both polymer totes, the polymer blend units will be stopped. 5.5 Polymer Blend Unit (M13-301, M13-302) One of the two polymer blend units will supply a dilute solution of polymer to the discharge of the operating influent pumps. The on screen selector for the desired blend unit is placed in the On position and the polymer dose mode is selected by the operator. The blend unit will be called to run as long as one or more polymer injection valve is open Polymer Dose Control MANUAL In manual mode the operator enters the desired diluted polymer flow rate and the desired diluted polymer concentration. These signals are sent to the polymer blend unit. AUTO In automatic mode flow pacing calculations are carried out to determine the desired diluted polymer flow rate. The desired polymer dose and the desired concentration for the diluted polymer are entered by the operator. Diluted Polymer Flow Rate in gph = 60 x D x Q 1440 x C x SG May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 9 of 25

10 In this equation, D is the desired dose (mg/l), Q is the plant flow rate (MGD), C is an adjustable polymer activity constant (%), and SG is the adjustable specific gravity of the polymer Alarms and Interlocks The blend unit generates a failure alarm if it fails to start when called or if sends a fail signal to the PLC. It also generates a low dilution water flow alarm. Blend unit operation is interlocked with the polymer injection valves; the blend units will not run if no injection valves are open. 5.6 Polymer Injection Valves (FV , 402, 403, 404) The polymer injection valves open to allow polymer to flow to the operating influent pumps. The valves may be operated in automatic or manual mode. MANUAL AUTO In manual mode each valve opens and closes in response to pushbuttons on the SCADA or OIT screen. In automatic mode each valve opens when its associated influent pump is running and closes when the pump stops Alarms and Interlocks The valves will trigger fail to open or fail to close alarms if they do not respond to a PLC command within an adjustable failure delay time. As mentioned above, polymer blend unit operation is interlocked with valve positions. If all of the injection valves are closed (as indicated by closed limit switches), the blend units will be locked out. 6 Sample SCADA Screens Sample SCADA screens for the ferric chloride and polymer system 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 operating scenarios that are not actually possible may be shown. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 10 of 25

11 6.1 Ferric Chloride Overview This screen presents an overview of the Ferric Chloride system. It shows operating status of all the major pieces of equipment as well as process values and critical alarms. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 11 of 25

12 6.2 Ferric Chloride Pump Control Pop-up The pop-up screen for a single-speed pump is illustrated to the right. With the right security access, an operator can manually start and stop the pump from this screen. Status indicators change color as well as text to show current status. The start and stop buttons are disabled when in automatic mode. The bell symbol indicates alarms are enabled for this equipment. A No symbol appears over the bell to show that alarms are disabled. This is a typical symbol used throughout. Clicking on the bell toggles the status of the alarm disable if the logged-in operator has high enough security access. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 12 of 25

13 6.3 Ferric Chloride Set points This screen allows an operator to edit the set points that control the ferric chloride dosing May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 13 of 25

14 6.4 Primary Polymer System Overview This screen presents an overview of the Primary Polymer system. It shows operating status of all the major pieces of equipment as well as process values and critical alarms. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 14 of 25

15 6.5 Primary Polymer Blend Unit Pop-up The pop-up screen for a single-speed pump is illustrated to the right. Its features are very similar to those of the ferric chloride pump control pop-up screen explained above. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 15 of 25

16 6.6 Primary Polymer Valve Control Pop-up The automatic valve screen allows an operator to manually open or close the valve or to select automatic operation and provides monitoring. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 16 of 25

17 6.7 Primary Polymer Set points This screen allows an operator to edit the set points for primary polymer system. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 17 of 25

18 7 Sample Panel View (OIT) Screens Sample screens for local Panel view operator interface for the ferric chloride and polymer system 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 Operator Interface Terminal (OIT) located at PLC 24. Please note that no process data is present in these screens and these were generated from the development environment. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 18 of 25

19 7.1 Ferric Chloride Overview This screen presents an overview of the Ferric Chloride system on the local Operator Interface Terminal (OIT). Its function is similar to the SCADA screen explained in section 6.1. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 19 of 25

20 7.2 Ferric Chloride Pump Control Pop-up The pop-up screen for a variablespeed pump is illustrated to the left. Its functions are similar to the SCADA screen explained in section 6.2. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 20 of 25

21 7.3 Ferric Chloride Set points This screen allows an operator to edit the set points that control the ferric chloride dosing from local OIT. Its function is similar to the SCADA screen explained in section 6.3. The calibration tables at the bottom of this screen are only available at the OIT and are used to characterize the flow response for each pump. The PLC calculates a desired flow rate from the dosing set points and then interpolates along the speed / flow curve established by these tables. It is imperative that accurate values be entered here for the system to deliver the correct dose. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 21 of 25

22 7.4 Primary Polymer System Overview This screen presents an overview of the Primary Polymer system on the local Operator Interface Terminal (OIT). Its functions are similar to the SCADA screen explained in section 6.4. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 22 of 25

23 7.5 Primary Polymer Blend Unit Control Pop-up The pop-up screen for a polymer blend unit is illustrated to the left. Its functions are similar to the SCADA screen explained in section 6.5. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 23 of 25

24 7.6 Primary Polymer Valve Control Pop-up The pop-up screen for an automatic valve is illustrated to the right. Its functions are similar to the SCADA screen explained in section 6.6. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 24 of 25

25 7.7 Primary Polymer Set points This screen allows an operator to edit the set points for the primary polymer system and its operation is similar to the SCADA screen explained in section 6.7. May 3, 2006 Rev. 1.0 PLC 24 Ferric Chloride and Polymer SCADA System Operation Manual Page 25 of 25