% Calc for acid pump control % % This is based on Ed Peltzers calcs for the HCL concentration and % predicted currents % % copyright (c) 2005 by W.J.Kirkwood of MBARI % February 2, 2005 % Last Modified 2/20/05 % Revision: 1.0 % % ///////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ % % clean up from last activity clear all ; clf; % pH_SetPoint = 7.3; % pH target value for control volume pH_Valid_Max = 8.0; % Maximum allowable value for inclusion in average pH_Valid_Min = 6.0; % Minimum allowable value for inclusion in average PumpH20 = 720; % Sets the water pump at 720 mL/min PumpAcid = 720; % Sets the acid pump at 720 mL/min PumpFixedFlow = 1440; % Sets the total pump flow at maximum current % Main Control Algorithm for Pumps % Concept: We would like the pump control to be exponential as the pH % wanders from the set point. This makes our control take the form % y = f(x) + K = a*2^(b*(x-h))+k % y is the acid pump commanded output % % Test matrices for pH change (bounce) % P = rand (1,10000); PP(1,:) = 1:1000; PP(2,:) = sin(rand (1,1000)); PP(3,:) = .01:.01:10; figure (1) plot (PP (1,:), PP(2,:)) % % a = scalar multiplier and moves the zero crossover on the x axis, also % change of sign of a flips the control curve around the x axis a = .1; % % b = exponential multiplier and sets the rate of change of the slope of % the control curve, also a sign change flips the control curve around the y axis b = 1.5; % % h is the x offset constant and sets the x crossover at y = 0 h = 1.0; % % K is the y offset constant and sets the y crossover at f(x) = 0 K = 0; % scaled in ml/min % % % pH Bounds lower is - .1 pH unit and upper is + .1 pH unit for deadband pH_BoundLow = pH_SetPoint - .10; pH_BoundHigh = pH_SetPoint + .10; % % Control Tests for sign on equation variables a, b, and K to invert curve % about dead band a1 = -a; b1 = -b; K1 = -K; MaxCurrent = 30; % ////////////////////// Pump Flow Control \\\\\\\\\\\\\\\\\\\\\\\ % Two pumps run as an inverse ratio to maintain a set over flow volume % uses the estimated current relationship. % ............ Note: Pumps ordered are 4.8 ml / rev ............... Current = input (' Enter current between 10 and 30 cm/sec : '); if Current < 10 Current = 10; elseif Current > 30 Current = 30; else Current = Current; end Current % Prints current for check if Current == 10 Total_Flow = 480; % Minimum ml/min from combined pumps PumpAcid = Total_Flow / 2; % PumpFixedFlow = Total_Flow - PumpAcid; % Default total output from pumps in ml/sec elseif Current == 30 Total_Flow = 1440; % Maximum ml/min from combined pumps PumpAcid = Total_Flow / 2; % PumpFixedFlow = Total_Flow - PumpAcid; % Default total output from pumps in ml/sec else Total_Flow = 1440 * (Current / MaxCurrent); % Minimum ml/min from combined pumps PumpAcid = Total_Flow / 2; % PumpFixedFlow = Total_Flow - PumpAcid; % Default total output from pumps in ml/sec end % pH_SetPoint = input (' Entet pH desired set point within 6.0 and 8.0 : '); if pH_SetPoint < 6.0 pH_SetPoint = 6.0; elseif pH_SetPoint > 8.0 pH_SetPoint = 8.0; else pH_SetPoint = pH_SetPoint; end % Initiate indices for counters i = 1; j = i; f = i; g = i; % PumpAcidMax = PumpAcid; % PumpAcidMin = -PumpAcid; % % Set scaling for pump adjust while i < 1000 if PP(2,i) > .33 PP(2,i) = .33; end if i < 200 | i > 600 pH_Measured (1,i) = 7.0 + PP(2,i); % fake high pH measurement for testing else pH_Measured (1,i) = 7.0 - PP(2,i); % fake low pH measurement for testing end if pH_SetPoint < pH_Measured % test for increase acid pumping pH_Delta = pH_SetPoint - pH_Measured; pH_Control = 10 * pH_Delta; pH_expo = b*(pH_Control - h); % just stuff to make following math easier pH_X = a*(2.0^pH_expo); PumpAdjNum = pH_X + K; elseif pH_SetPoint > pH_Measured % test for increase acid pumping pH_Delta = pH_Measured - pH_SetPoint; pH_Control = 10 * pH_Delta; pH_expo = b*(pH_Control - h); % just stuff to make folliwng math easier pH_X = a*(2.0^pH_expo); PumpAdjNum = pH_X + K; else pH % ..... inserts model Data for plotting purposes ...... pH_Data (1,i) = PumpAdjNum; pH_Data (2,i) = PP(2,i); pH_Data (3,i) = pH_Measured pH_Data (4,i) = pH_Delta; pH_Data (5,i) = pH_Control; % pH_expo1 = b1*(pH1_Control - h); % pH_X1 = a1*(2.0^pH_expo); % PumpAdjNum1 = pH_X1 + K1; % pH_Data(5,i) = PumpAdjNum1; % pH_Data (6,j) = 0; % pH_expo1; % pH_Data (7,f) = 0; % pH_X1; % pH_Data (8,f) = pH1_Control; % pH_Data (9,i) = pH_BoundHigh - pH_SetPoint; pH_Data (10,i) = -pH_Data (9,i); % pH_Control = pH_Control + .1; % pH1_Control = pH1_Control - .1; PumpAdjNum = pH_X + K; % sets the amount of pump adjustment if PumpAdjNum > 1 PumpAdjNum = 1; end i = i+1; j = i; f = i; end % figure(2) scatter (pH_Data(4,:,:),pH_Data(1,:,:)) hold on % plot (pH_Data(8,:,:),pH_Data(5,:,:)) plot (pH_Data(4,:,:),pH_Data(9,:,:),'--r') % plot (pH_Data(8,:,:),pH_Data(10,:,:),'--r') % Acid Flow Clipping Equation goes here % % if (PumpAdjNum > PumpAcidMax ) % NewAcidNum = PumpAcidMax; % elseif (PumpAdjNum < PumpAcidMin ) % NewAcidNum = PumpAcidMin; % else % NewAcidNum = PumpAdjNum; % end % % Pump adjust test vs. pH % % if pH_Control > pH_BoundMax % PumpCmd % % % slaving acid pump rate to the pH_Control variable % pH_Delta = pH_SetPoint - pH_Control; % pH offset from desired value % % tests and settings for acid volume change % if pH_Delta < 0 % PumpAdjNum = pH_Delta_Old - pH_Delta; % PumpAcid = PumpAcid; % no change to pump input % PumpFixedFlow = Total_Flow - PumpAcid; % Default total output from pumps in ml/sec % elseif pH_Delta > 0 % PumpAcid = Total_Flow / 2; % PumpFixedFlow = Total_Flow - PumpAcid; % Default total output from pumps in ml/sec % else % PumpAcid = PumpAcid; % no change in pump flow % end % pH_Delta_Old = pH_Delta; % resets pH for comparison to last value % pH_PumpAcid_Old = pH_PumpAcid; % resets Acid Pump flow rate comparion to last value % % Shutdown and clean up % Stop time % fclose(pH_port1) % fclose(pH_port2) % fcloae(pH_port3)