Table 2 — Letter codes for process variables and control functions.xls

	A	B	C	D	E
1	Table 2 — Letter codes for process variables and control functions
2	Letter code	Process variables	Application notes	Control functions	Application notes
3	A	Electric voltage		Alarming, message	9
4	B
5	C	Electric current		Control (closed loop)
6	D	Density
7	E	Electric or electromagnetic variables (except A and C)	1
8	F	Flow rate
9	G	Distance, position or length
10	H	Human observation	2
11	1	Not to be used		Indicating
12	I	Power
13	K	Time
14	L	Level	3
15	M	Moisture, humidity
16	N
17	0	Not to be used
18	P	Pressure, vacuum	3
19	Q	Quality	4
20	R	Radiation	5	Recording
21	S	Speed, frequency	6	Switching (open loop)
22	T	Temperature
23	U	Multivariable	7
24	V
25	w	Weight, force
26	X
27	Y
28	Z	Number of events, quantity	8	Switching (open-loop) safety/protection relevant	10
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100