3 #==BEGIN function definition==
4 yell
() { echo "$0: $*" >&2; } # print script path and all args to stderr
5 die
() { yell
"$*"; exit 111; } # same as yell() but non-zero exit status
6 try
() { "$@" || die
"cannot $*"; } # runs args as command, reports args if command fails
8 # Desc: Calculates control variable (CV) given setpoint (SP) and
9 # process variable (PV). Uses proportional integral (PI)
11 # Usage: update_pi arg1 arg2 arg3 arg4 arg5
13 # Input: arg1: path_loop_name (control loop name path)
14 # arg2: var_pv (process variable)
15 # arg3: var_sp (set point)
16 # arg4: tune_p (proportional tuning factor)
17 # arg5: tune_i (integral tuning factor)
18 # Output: stdout: var_cv (control variable)
23 # file: path_sum (saves updated sum state)
24 # Example: update_pi /dev/shm/DC1.AC 1.0 3.0 2.0 3.0
25 # Depends: bc, gnu coreutils 8.30, yell(), try()
26 local var_sp var_pv var_cv
;
30 local path_sum path_var_sp path_var_pv path_tune_p path_tune_i
;
34 path_var_pv
="$path_loop_name".pv
35 var_pv
="$2"; # read provided process variable
37 path_var_sp
="$path_loop_name".sp
38 if [[ -f "$path_var_sp" ]]; then
39 var_sp
="$(cat "$path_var_sp" | head -n1)";
44 path_tune_p
="$path_loop_name".tune_p
45 if [[ -f "$path_tune_p" ]]; then
46 tune_p
="$(cat "$path_tune_p" | head -n1)";
51 path_tune_i
="$path_loop_name".tune_i
52 if [[ -f "$path_tune_i" ]]; then
53 tune_i
="$(cat "$path_tune_i" | head -n1)";
58 path_sum
="$path_loop_name".
sum
59 if [[ -f "$path_sum" ]]; then
60 sum="$(cat "$path_sum" | head -n1)";
65 #yell "DEBUG:path_loop_name:$path_loop_name";
66 #yell "DEBUG:var_pv:$var_pv";
67 #yell "DEBUG:var_sp:$var_sp";
68 #yell "DEBUG:tune_p:$tune_p";
69 #yell "DEBUG:tune_i:$tune_i";
71 error
="$(try echo "$var_sp - $var_pv" | bc -l)";
72 #yell "DEBUG:error:$error";
73 sum="$(try echo "$sum + $error" | bc -l)";
74 #yell "DEBUG:sum:$sum";
75 term_p
="$(try echo "$tune_p * $error" | bc -l)";
76 #yell "DEBUG:term_p:$term_p";
77 term_i
="$(try echo "$tune_i * $sum" | bc -l)";
78 #yell "DEBUG:term_i:$term_i";
79 var_cv
="$(try echo "$term_p + $term_i" | bc -l)";
80 #yell "DEBUG:var_cv:$var_cv";
82 # Write variables to memory
83 echo "$sum" > "$path_sum";
84 echo "$var_sp" > "$path_var_sp";
85 echo "$var_pv" > "$path_var_pv";
86 echo "$tune_p" > "$path_tune_p";
87 echo "$tune_i" > "$path_tune_i";
89 # Output control variable to stdout
92 #yell "DEBUG:=============END_ROUND===============";
94 #==END function definition==
96 #==BEGIN Example code==
97 path_loop_name
="/tmp/DC1.AC";
102 try
rm "$path_loop_name"*
105 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
106 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
107 yell
"DEBUG:output:$output";
109 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
110 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
111 yell
"DEBUG:output:$output";
113 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
114 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
115 yell
"DEBUG:output:$output";
117 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
118 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
119 yell
"DEBUG:output:$output";
121 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
122 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
123 yell
"DEBUG:output:$output";
125 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
126 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
127 yell
"DEBUG:output:$output";
129 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
130 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
131 yell
"DEBUG:output:$output";
133 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
134 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
135 yell
"DEBUG:output:$output";
137 output
="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
138 yell
"DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
139 yell
"DEBUG:output:$output";
140 #==END Example code==
142 # Author: Steven Baltakatei Sandoval