37 pidctrl_init(struct pidctrl *pc, int interval, int setpoint, int bound,  in pidctrl_init()  argument
41 	bzero(pc, sizeof(*pc));  in pidctrl_init()
42 	pc->pc_setpoint = setpoint;  in pidctrl_init()
43 	pc->pc_interval = interval;  in pidctrl_init()
44 	pc->pc_bound = bound * setpoint * Kid;  in pidctrl_init()
45 	pc->pc_Kpd = Kpd;  in pidctrl_init()
46 	pc->pc_Kid = Kid;  in pidctrl_init()
47 	pc->pc_Kdd = Kdd;  in pidctrl_init()
51 pidctrl_init_sysctl(struct pidctrl *pc, struct sysctl_oid_list *parent)  in pidctrl_init_sysctl()  argument
55 	    &pc->pc_error, 0, "Current difference from setpoint value (P)");  in pidctrl_init_sysctl()
57 	    &pc->pc_olderror, 0, "Error value from last interval");  in pidctrl_init_sysctl()
59 	    &pc->pc_integral, 0, "Accumulated error integral (I)");  in pidctrl_init_sysctl()
61 	    &pc->pc_derivative, 0, "Error derivative (D)");  in pidctrl_init_sysctl()
63 	    &pc->pc_input, 0, "Last controller process variable input");  in pidctrl_init_sysctl()
65 	    &pc->pc_output, 0, "Last controller output");  in pidctrl_init_sysctl()
67 	    &pc->pc_ticks, 0, "Last controller runtime");  in pidctrl_init_sysctl()
69 	    &pc->pc_setpoint, 0, "Desired level for process variable");  in pidctrl_init_sysctl()
71 	    &pc->pc_interval, 0, "Interval between calculations (ticks)");  in pidctrl_init_sysctl()
73 	    &pc->pc_bound, 0, "Integral wind-up limit");  in pidctrl_init_sysctl()
75 	    &pc->pc_Kpd, 0, "Inverse of proportional gain");  in pidctrl_init_sysctl()
77 	    &pc->pc_Kid, 0, "Inverse of integral gain");  in pidctrl_init_sysctl()
79 	    &pc->pc_Kdd, 0, "Inverse of derivative gain");  in pidctrl_init_sysctl()
83 pidctrl_classic(struct pidctrl *pc, int input)  in pidctrl_classic()  argument
88 	error = pc->pc_setpoint - input;  in pidctrl_classic()
89 	pc->pc_ticks = ticks;  in pidctrl_classic()
90 	pc->pc_olderror = pc->pc_error;  in pidctrl_classic()
93 	Kpd = MAX(pc->pc_Kpd, 1);  in pidctrl_classic()
94 	Kid = MAX(pc->pc_Kid, 1);  in pidctrl_classic()
95 	Kdd = MAX(pc->pc_Kdd, 1);  in pidctrl_classic()
98 	pc->pc_error = error;  in pidctrl_classic()
99 	pc->pc_integral =  in pidctrl_classic()
100 	    MAX(MIN(pc->pc_integral + error, pc->pc_bound), -pc->pc_bound);  in pidctrl_classic()
101 	pc->pc_derivative = error - pc->pc_olderror;  in pidctrl_classic()
104 	output = (pc->pc_error / Kpd) + (pc->pc_integral / Kid) +  in pidctrl_classic()
105 	    (pc->pc_derivative / Kdd);  in pidctrl_classic()
107 	pc->pc_output = output;  in pidctrl_classic()
108 	pc->pc_input = input;  in pidctrl_classic()
114 pidctrl_daemon(struct pidctrl *pc, int input)  in pidctrl_daemon()  argument
119 	error = pc->pc_setpoint - input;  in pidctrl_daemon()
126 	if ((u_int)ticks - pc->pc_ticks >= pc->pc_interval) {  in pidctrl_daemon()
127 		pc->pc_ticks = ticks;  in pidctrl_daemon()
128 		pc->pc_olderror = pc->pc_error;  in pidctrl_daemon()
129 		pc->pc_output = pc->pc_error = 0;  in pidctrl_daemon()
132 		error -= pc->pc_error - pc->pc_output;  in pidctrl_daemon()
136 	Kpd = MAX(pc->pc_Kpd, 1);  in pidctrl_daemon()
137 	Kid = MAX(pc->pc_Kid, 1);  in pidctrl_daemon()
138 	Kdd = MAX(pc->pc_Kdd, 1);  in pidctrl_daemon()
141 	pc->pc_error += error;  in pidctrl_daemon()
142 	pc->pc_integral =  in pidctrl_daemon()
143 	    MAX(MIN(pc->pc_integral + error, pc->pc_bound), 0);  in pidctrl_daemon()
144 	pc->pc_derivative = pc->pc_error - pc->pc_olderror;  in pidctrl_daemon()
147 	output = (pc->pc_error / Kpd) + (pc->pc_integral / Kid) +  in pidctrl_daemon()
148 	    (pc->pc_derivative / Kdd);  in pidctrl_daemon()
149 	output = MAX(output - pc->pc_output, 0);  in pidctrl_daemon()
151 	pc->pc_output += output;  in pidctrl_daemon()
152 	pc->pc_input = input;  in pidctrl_daemon()