function [exectime, data] = pidcode2(seg, data)switch seg,     case 1,  data.t = ttCurrentTime;  exectime = 0; case 2,  r = ttAnalogIn(data.rChan); % Read reference  y = ttAnalogIn(data.yChan); % Read process output  data = pidcalc(data, r, y); % Calculate PID action  exectime = 0.002; case 3,  ttAnalogOut(data.uChan, data.u); % Output control signal  data.t = data.t + data.h;  ttSleepUntil(data.t); % Sleep until next period  exectime = 0; case 4,  ttSetNextSegment(2); % loop to segment 2  exectime = 0;  end