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Anemometer With, Photochopper Output

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SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES 02: Do (P86) 1: 41 Set Port 1 High 03: Excitation with Delay (P22) 1: 2 Ex Channel 2: 0 Delay w/Ex (units = 0.01 sec) 3: 15 Delay after Ex (units = 0.01 sec) 4: 0 mV Excitation 04: Volts (SE) (P1) 1: 1 Reps 2: 5 2500 mV Slow Range 3: 2 SE Channel 4: 2 Loc [ RH ] 5: .1 Mult 6: 0 Offset 05: Do (P86) 1: 51 Set Port 1 Low 7.4 ANEMOMETER WITH PHOTOCHOPPER OUTPUT An anemometer with a photochopper transducer produces a pulse output which is measured by the CR510's Pulse Count Instruction. The Pulse Count Instruction with a Configuration Code of 20, measures "high frequency pulses", "discards data from excessive intervals", and "outputs the reading as a frequency" (Hz = pulses per second). The frequency output is the only output option that is independent of the scan rate. The anemometer used in this example is the R. M. Young Model 12102D Cup Anemometer, with a 10 window chopper wheel. The photochopper circuitry is powered from the CR510 12 V supply; AC power or back-up batteries should be used to compensate for the increased current drain. Wind speed is desired in meters per second (m/s). There is a pulse each time a window in the chopper wheel, which revolves with the cups, allows light to pass from the source to the photoreceptor. Because there are 10 windows in the chopper wheel, there are 10 pulses per revolution. Thus, 1 revolution per minute (rpm) is equal to 10 pulses per 60 seconds (1 minute) or 6 rpm = 1 pulse per second (Hz). The manufacturer's calibration for relating wind speed to rpm is: Wind(m/s) = (0.01632 m/s)/rpm ∗ Xrpm + 0.2 m/s The result of the Pulse Count Instruction (Configuration Code = 20) is X pulses per sec. (Hz). The multiplier and offset to convert XHz to meters per second are: Wind (m/s) = (0.01632 m/s)/rpm x (6 rpm/Hz) x XHz + 0.2 m/s Wind (m/s) = (0.09792 m/s)/Hz x XHz + 0.2 m/s PROGRAM 01: Pulse (P3) 1: 1 Reps 2: 1 Pulse Input Channel 3: 20 High Frequency, Output Hz 4: 10 Loc [ WS_mph ] 5: .09792 Mult 6: .2 Offset CR510 FIGURE 7.4-1. Wiring Diagram for Anemometer 7-3

Section	Page
Revision and Copyright Information	1
Warranty and Assistance	3
Table of Contents	5
Features of CR510	9
Selected Operating Details	11
Cautionary Notes	12
CR510 DATALOGGER OVERVIEW	13
OV1. PHYSICAL DESCRIPTION	13
OV1.1 ANALOG INPUTS	13
OV1.2 EXCITATION OUTPUTS	14
OV1.3 PULSE INPUTS	14
OV1.4 DIGITAL I/O PORTS	14
OV1.5 ANALOG GROUND (AG)	14
OV1.6 12V, POWER GROUND (G), AND EARTH TERMINALS	14
OV1.7 5V OUTPUT	14
OV1.8 SERIAL I/O	14
OV1.9 CONNECTING POWER TO THE CR510	14
OV2. MEMORY AND PROGRAMMING CONCEPTS	15
OV2.1 INTERNAL MEMORY	15
OV2.2 PROGRAM TABLES, EXECUTION INTERVAL AND OUTPUT INTERVALS	17
OV2.2.1 THE EXECUTION INTERVAL	17
OV2.2.2. THE OUTPUT INTERVAL	18
OV2.3 CR510 INSTRUCTION TYPES	18
OV3. COMMUNICATING WITH CR510	20
OV3.1 KEYBOARD/DISPLAY	20
OV3.1.1 FUNCTIONAL MODES	20
OV3.1.2 KEY DEFINITION	20
OV3.2 USING COMPUTER WITH DATALOGGER SUPPORT SOFTWARE	21
OV3.3 ASCII TERMINAL OR COMPUTER WITH TERMINAL EMULATOR	21
OV4. PROGRAMMING THE CR510	21
OV4.1 PROGRAMMING SEQUENCE	22
OV4.2 INSTRUCTION FORMAT	22
OV4.3 ENTERING A PROGRAM	23
OV5. PROGRAMMING EXAMPLES	23
OV5.1 SAMPLE PROGRAM 1	24
OV5.2 EDITING AN EXISTING PROGRAM	26
OV5.3 SETTING THE DATALOGGER TIME	27
OV6. DATA RETRIEVAL OPTIONS	28
OV7. SPECIFICATIONS	30
Section 1	31
1.1 DATALOGGER PROGRAMS - 1, 2, 3, AND 4 MODES	31
1.1.1 EXECUTION INTERVAL	31
1.1.2 SUBROUTINES	32
1.1.3 TABLE PRIORITY/INTERRUPTS	32
1.1.4 *4 PARAMETER ENTRY TABLE	32
ASSIGNING PARAMETERS TO *4 - EDLOG	32
CHANGING VALUES IN *4 TABLE	33
1.1.5 COMPILING A PROGRAM	33
1.2 SETTING AND DISPLAYING THE CLOCK - *5 MODE	34
1.3 DISPLAYING/ALTERING INPUT MEMORY, FLAGS, AND PORTS - *6 MODE	34
1.3.1 DISPLAYING AND ALTERING INPUT STORAGE WITH THE KEYBOARD DISPLAY	34
1.3.2 DISPLAYING AND TOGGLING USER FLAGS	35
1.3.3 DISPLAYING AND TOGGLING PORTS	35
1.4 COMPILING AND LOGGING DATA - *0 MODE	35
1.5 MEMORY ALLOCATION - *A	35
1.5.1 INTERNAL MEMORY	35
1.5.2 *A MODE	38
1.6 MEMORY TESTING AND SYSTEM STATUS - *B	39
1.7 *C MODE -- SECURITY	41
1.8 *D MODE -- SAVE OR LOAD PROGRAM	41
1.8.1 INTERNAL FLASH PROGRAM STORAGE	41
1.8.2 PROGRAM TRANSFER WITH STORAGE MODULE	42
1.8.3 FULL/HALF DUPLEX	43
1.8.4 SET DATALOGGER ID	43
1.8.5 SETTING POWERUP OPTIONS	43
Section 2	45
2.1 FINAL STORAGE AREAS, OUTPUT ARRAYS, AND MEMORY POINTERS	45
2.2 DATA OUTPUT FORMAT AND RANGE LIMITS	47
2.2.1 RESOLUTION AND RANGE LIMITS	47
2.2.2 INPUT AND INTERMEDIATE STORAGE DATA FORMAT	47
2.3 DISPLAYING STORED DATA ON KEYBOARD/DISPLAY - ?7 MODE	47
Section 3	49
3.1 PARAMETER DATA TYPES	49
3.2 REPETITIONS	49
3.3 ENTERING NEGATIVE NUMBERS	49
3.4 INDEXING INPUT LOCATIONS	49
3.5 VOLTAGE RANGE AND OVERRANGE DETECTION	50
3.6 OUTPUT PROCESSING	50
3.7 USE OF FLAGS: OUTPUT AND PROGRAM CONTROL	51
3.7.1 THE OUTPUT FLAG	51
3.7.2 THE INTERMEDIATE PROCESSING DISABLE FLAG	51
3.7.3 USER FLAGS	52
3.8 PROGRAM CONTROL LOGICAL CONSTRUCTIONS	52
3.8.1 IF THEN/ELSE COMPARISONS	53
3.8.2 NESTING	54
3.9 INSTRUCTION MEMORY AND EXECUTION TIME	55
3.10 ERROR CODES	59
Section 4	61
4.1 ON-LINE DATA TRANSFER - INSTRUCTION 96	61
4.2 MANUALLY INITIATED DATA OUTPUT - *8 MODE	63
4.3 PRINTER OUTPUT FORMATS	63
4.3.1 PRINTABLE ASCII FORMAT	63
4.3.2 COMMA SEPARATED ASCII	64
4.4 STORAGE MODULE	64
4.4.1 STORAGE MODULE ADDRESSING	64
4.4.2 STORAGE MODULE USE WITH INSTRUCTION 96	65
4.4.3 *8 DUMP TO STORAGE MODULE	65
4.5 *9 MODE -- SM192/716 STORAGE MODULE COMMANDS	65
Section 5	67
5.1 TELECOMMUNICATIONS COMMANDS	67
5.2 REMOTE PROGRAMMING OF THE CR510	70
Section 6	71
6.1 PIN DESCRIPTION	71
6.2 ENABLING AND ADDRESSING PERIPHERALS	72
6.2.1 PIN-ENABLED PERIPHERALS	72
6.2.2 ADDRESSED PERIPHERALS	72
6.3 RING INTERRUPTS	73
6.4 INTERRUPTS DURING DATA TRANSFER	73
6.5 MODEM/TERMINAL PERIPHERALS	74
6.6 SYNCHRONOUS DEVICE COMMUNICATION	74
6.7 MODEM/TERMINAL AND COMPUTER REQUIREMENTS	75
6.7.1 SC32A INTERFACE TO COMPUTER	75
6.7.2 SC932 INTERFACE TO MODEMS	76
6.7.3 COMPUTER/TERMINAL REQUIREMENTS	76
6.7.3 COMMUNICATION PROTOCOL/TROUBLE SHOOTING	77
Section 7	79
7.1 SINGLE ENDED VOLTAGE107 TEMPERATURE PROBE	79
7.2 DIFFERENTIAL VOLTAGE MEASUREMENT	79
7.3 HMP45C TEMPERATURE AND RH PROBE	80
7.4 ANEMOMETER WITH PHOTOCHOPPER OUTPUT	81
7.5 TIPPING BUCKET RAIN GAGE WITH LONG LEADS	82
7.6 100 OHM PRT IN 4 WIRE HALF BRIDGE	82
7.7 100 OHM PRT IN 3 WIRE HALF BRIDGE	84
7.8 100 OHM PRT IN 4 WIRE FULL BRIDGE	85
7.9 PRESSURE TRANSDUCER - 4 WIRE FULL BRIDGE	86
7.10 LYSIMETER - 6 WIRE FULL BRIDGE	87
7.11 227 GYPSUM SOIL MOISTURE BLOCK	89
7.12 NONLINEAR THERMISTOR IN HALF BRIDGE	90
7.13 WATER LEVEL - GEOKON'S VIBRATING WIRE PRESSURE SENSOR	91
7.14 4 TO 20 MA SENSOR USING CURS100 TERMINAL INPUT MODULE	95
Section 8	97
8.1 COMPUTATION OF RUNNING AVERAGE	97
8.2 RAINFALL INTENSITY	98
8.3 SUB 1 MINUTE OUTPUT INTERVAL SYNCHED TO REAL TIME	99
8.4 SWITCH CLOSURES ON CONTROL PORTS (RAIN GAGE)	99
8.5 CONVERTING 0-360 WIND DIRECTION OUTPUT TO 0-540 FOR STRIP CHART	100
8.6 USE OF 2 FINAL STORAGE AREAS - SAVING DATA PRIOR TO EVENT	101
8.7 LOGARITHMIC SAMPLING USING LOOPS	102
Section 9	105
1 SINGLE-ENDED VOLTS	105
2 DIFFERENTIAL VOLTS	105
3 PULSE COUNT	105
4 EXCITE, DELAY, AND MEASURE	107
5 AC HALF BRIDGE	108
6 FULL BRIDGE WITH SINGLE DIFFERENTIAL MEASUREMENT	108
7 THREE WIRE HALF BRIDGE	108
8 DIFFERENTIAL VOLTAGE WITH EXCITATION AND DELAY	109
9 FULL BRIDGE WITH EXCITATION COMPENSATION	109
10 BATTERY VOLTAGE	110
11 107 THERMISTOR PROBE	110
12 207 RELATIVE HUMIDITY PROBE	110
16 TEMPERATURE FROM PLATINUM R.T.D.	111
17 INTERNAL TEMPERATURE	111
18 MOVE TIME TO INPUT LOCATION	111
19 MOVE SIGNATURE INTO INPUT LOCATION	112
20 PORT SET	112
21 PULSE PORT WITH DURATION	112
22 EXCITATION WITH DELAY	113
24 CALIBRATION	113
25 PORT READ	113
26 TIMER	113
27 PERIOD MEASUREMENT	114
28 VIBRATING WIRE MEASUREMENT	114
29 INW PS9105E	115
105 SDI-12 RECORDER	115
106 SDI-12 SENSOR	117
114 SET TIME	119
117 READ DATALOGGER ID	119
130 ERROR MONITOR	119
131 ENHANCED VIBRATING WIRE MEASUREMENT	120
Section 10	121
30 Z = F X 10N	121
31 Z = X	121
32 Z = Z + 1	121
33 X + Y	121
34 X + F	121
35 X - Y	121
36 X * Y	122
37 X * F	122
38 X / Y	122
39 SQUARE ROOT	122
40 LN(X)	122
41 EXP(X)	122
42 1/X	122
43 ABS(X)	123
44 FRACTIONAL VALU E OF X	123
45 INTEGER VALUE OF X	123
46 X MOD F	123
47 XY	123
48 SIN(X)	123
49 SPATIAL MAXIMUM	123
50 SPATIAL MINIMUM	124
51 SPATIAL AVERAGE	124
52 RUNNING AVERAGE	124
53 SCALING ARRAY WITH MULTIPLIER AND OFFSET	124
54 BLOCK MOVE	125
55 5TH ORDER POLYNOMIAL	125
56 SATURATION VAPOR PRESSURE	125
58 LOW PASS FILTER	126
59 BRIDGE TRANSFORM	126
61 INDIRECT INDEXED MOVE	126
63 PARAMETER EXTENSION	126
65 BULK LOAD	127
66 ARCTAN	127
68 EXTENDED PARAMETERS 4 DIGIT	127
Section 11	129
69 WIND VECTOR	129
70 SAMPLE	130
71 AVERAGE	131
72 TOTALIZE	131
73 MAXIMIZE	131
74 MINIMIZE	131
75 STANDARD AND WEIGHTED VALUE HISTOGRAM	131
77 RECORD REAL TIME	132
78 SET HIGH OR LOW RESOLUTION DATA STORAGE FORMAT	133
79 SAMPLE ON MAXIMUM OR MINIMUM	133
80 SET ACTIVE STORAGE AREA	133
82 STANDARD DEVIATION IN TIME	133
Section 12	135
83 IF CASE X < F	135
85 LABEL SUBROUTINE	135
86 DO	136
87 LOOP	136
88 IF X COMPARED TO Y	137
89 IF X COMPARED TO F	137
90 STEP LOOP INDEX	137
91 IF FLAG / PORT / MODEM	137
92 IF TIME	138
93 BEGIN CASE STATEMENT	138
94 ELSE	138
95 END	139
96 ACTIVATE SERIAL DATA OUTPUT	139
97 INITIATE TELECOMMUNICATIONS	140
98 SEND CHARACTER	142
111 RUN PROGRAM FROM FLASH	142
120 TGT1 TELONICS GOES	142
121 ARGOS	143
123 AUTOMATIC PROGRAMMING OF A TGT1	143
Section 13	145
13.1 FAST AND SLOW MEASUREMENT SEQUENCE	145
13.2 SINGLE-ENDED AND DIFFERENTIAL VOLTAGE MEASUREMENTS	146
13.3 THE EFFECT OF SENSOR LEAD LENGTH ON THE SIGNAL SETTLING TIME	147
13.3.1 THE INPUT SETTLING TIME CONSTANT	148
13.3.2 EFFECT OF LEAD LENGTH ON SIGNAL RISE TIME	150
13.3.3 TRANSIENTS INDUCED BY SWITCHED EXCITATION	151
13.3.4 SUMMARY OF SETTLING ERRORS FOR CAMPBELL SCIENTIFIC RESISTIVE SENSORS	152
13.4 BRIDGE RESISTANCE MEASUREMENTS	156
13.5 RESISTANCE MEASUREMENTS REQUIRING AC EXCITATION	160
13.6 CALIBRATION PROCESS	161
Section 14	163
14.1 PROTECTION FROM THE ENVIRONMENT	163
14.2 POWER REQUIREMENTS	163
14.3 CAMPBELL SCIENTIFIC POWER SUPPLIES	164
14.3.1 BPALK ALKALINE POWER SUPPLY	164
14.3.2 PS12LA LEAD ACID POWER SUPPLY	165
14.3.3 PS512M VOLTAGE REGULATOR WITH NULL MODEM PORTS	166
14.4 SOLAR PANELS	167
14.5 DIRECT BATTERY CONNECTION TO THE CR510 TERMINAL STRIP	167
14.6 VEHICLE POWER SUPPLY CONNECTIONS	167
14.7 GROUNDING	168
14.7.1 PROTECTION FROM LIGHTNING	168
14.7.2 EFFECT OF GROUNDING ON MEASUREMENTS: COMMON MODE RANGE	169
14.8 TERMINAL STRIP	169
14.9 USE OF DIGITAL I/O PORT (C1) FOR SWITCHING RELAYS	169
14.10 MAINTENANCE	171
14.10.1 DESICCANT	171
14.10.2 REPLACING THE INTERNAL BATTERY	171
Appendix A	173
Appendix B	177
B.1 TELECOMMUNICATIONS COMMAND WITH BINARY RESPONSES	177
B.2 FINAL STORAGE FORMAT	179
B.3 GENERATION OF SIGNATURE	181
B.4 *D COMMANDS TO TRANSFER PROGRAM WITH COMPUTER	181
Appendix C	183
Appendix D	185
D.1 INTRODUCTION	185
D.2 EXAMPLE PHONE CALLBACK PROGRAM BASED ON A CONDITION	185
D.3 PC208 DOS COMPUTER SOFTWARE AND IT’S COMPUTER SETUP	186
Appendix E	189
E.1 INTRODUCTION	189
E.2 PROGRAMMING	189
E.3 PROGRAMMING FOR THE CALLING CR510	189
E.3.1 INSTRUCTION 97	189
E.3.2 INSTRUCTION 63	190
E.4 REMOTE DATALOGGER PROGRAMMING	191
Appendix F	193
F.1 TERMINOLOGY	193
F.2 COMMUNICATIONS AND COMPATIBILITY	193
F.2.1 RF COMMUNICATIONS	194
F.2.2 CR510 TO CR510 OR CR10(X) COMMUNICATION	194
F.3 MORE ON MODBUS	194
APPENDIX G. TD OPERATING SYSTEM ADDENDUM FORCR510, CR10X, AND CR23X MANUALS	197
Revision and Copyright Information	199
TD and PakBus Operating System Addendum for CR510, CR10X, and CR23X Manuals	201
AD1 Major Differences	201
AD2 Overview of Data Storage Tables	202
AD3 Converting an existing program to Table Based OS	202
AD3.1 Programming changes	202
AD3.2 Making the Changes with Edlog	203
AD4 Summary of Differences from the Datalogger Manual:	204
MEASUREMENT AND CONTROL MODULE OVERVIEW	207
OV4. PROGRAMMING THE CR10X	207
OV4.1 FUNCTIONAL MODES	207
OV4.2 KEY DEFINITION	207
OV4.3 PROGRAMMING SEQUENCE	208
OV4.4 INSTRUCTION FORMAT	208
OV4.5 ENTERING A PROGRAM	209
OV5. PROGRAMMING EXAMPLES	209
OV5.1 SAMPLE PROGRAM 1	209
OV5.2 SAMPLE PROGRAM 2	211
OV5.3 EDITING AN EXISTING PROGRAM	213
OV6. DATA RETRIEVAL OPTIONS	213
SECTION 1. FUNCTIONAL MODES	215
1.5 MEMORY ALLOCATION - ?A	215
1.5.1 INTERNAL MEMORY	215
1.5.2 ?A MODE	216
MEMORY TESTING AND SYSTEM STATUS - ?B	217
1.7 *C MODE -- SECURITY	217
1.8 *D MODE – TRANSFER PROGRAMS, GENERAL SETTING	217
1.8.1 ERASING CURRENT PROGRAM	218
1.8.2 PROGRAM TRANSFER WITH STORAGE MODULE	218
1.8.3 FULL/HALF DUPLEX	218
1.8.4 SET DATALOGGER ID	218
1.8.5 SETTING POWERUP OPTIONS	218
1.8.6 SET INITIAL BAUD	219
1.8.7 SET PROGRAM COMPILE OPTION	219
1.8.8 SET PAKBUS ADDRESS	219
1.8.9 ALLOCATE MEMORY FOR GENERAL PURPOSE FILES	220
1.8.10 VIEW ROUTING TABLE	220
1.8.11 SET PAKBUS ROUTER BEACON INTERVAL	220
1.8.12 PAKBUS NEIGHBOR FILTER	220
1.9 *9 DATA TABLES SIZES.	221
SECTION 2. INTERNAL DATA STORAGE	223
2.1 FINAL STORAGE AND DATA TABLES	223
2.1.1 TIME AND TIMESTAMPS	223
2.1.2 RECORD NUMBERS	224
2.1.3 TABLES AND FIELDS.	224
2.2 DATA OUTPUT FORMAT AND RANGE LIMITS	225
2.2.1 RESOLUTION AND RANGE LIMITS	225
2.2.2 HIGH RESOLUTION FINAL STORAGE DATA, INPUT, AND INTERMEDIATE STORAGE DATA FORMAT	225
2.3 DISPLAYING STORED DATA ON KEYBOARD/DISPLAY *7 MODE.	225
SECTION 3. INSTRUCTION SET BASICS	227
SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES	229
8.1 COMPUTATION OF RUNNING AVERAGE	229
8.2 RAINFALL INTENSITY	230
8.3 USING CONTROL PORTS AND LOOP TO RUN AM416 MULTIPLEXER	231
8.4 INTERRUPT SUBROUTINE USED TO COUNT SWITCH CLOSURES (RAIN GAGE)	233
8.5 SDM-A04 ANALOG OUTPUT MULTIPLEXER TO STRIP CHART	234
8.6 CONVERTING 0-360 WIND DIRECTION OUTPUT TO 0-540 FOR STRIP CHART	235
8.7 LOGARITHMIC SAMPLING USING LOOPS	235
SECTION 9. INPUT/OUTPUT INSTRUCTIONS	239
SECTION 11. OUTPUT PROCESSING INSTRUCTIONS	241
SECTION 12. PROGRAM CONTROL INSTRUCTIONS	243
Wireless Networks	243
Datalogger Requirements	243
Communication Notes	243
PakBus Get/Send Locations (P190)	245
Port	246
Address	246
PakBus Communication	247
Modbus Communication	247
Command	247
Security	248
Remote Location/Coil/Register	248
PakBus Communication	248
Modbus Communication	248
Remote Location	249
PakBus Communication	249
Modbus Communication	249
Swath	249
PakBus Communication	249
Modbus Communication	249
Local Location	249
PakBus Communication	249
Modbus Communication	249
Result Code Location	250
Send Final Storage Data (P191)	250
Table ID	250
Flag	250
Send Message (P192)	250
Message Type	251
Wireless Network Master (P193)	251
Number of Remotes	252
First Remote Address	252
Time into Transmit Interval	252
Example	252
Transmit Interval	252
Example	253
Transmit Delay Between Remotes	253
Example	253
Swath to Receive	253
First Location for Data Received	253
Swath to Send	254
First Location to Send	254
Result Code Location	254
Seconds Until Transmit (P194)	254
Location with Seconds Until Transmit	255
Use Remote Clock Report (P195)	255
Address	255
Wireless Network Remote (P196)	255
Swath to Receive From Master	256
First Location for Data Received	256
Security	256
Swath to Send	256
First Location to Send	256
Result Code Location	257
Force Route (P197)	257
Neighbor's Address	257
Hops	257
Set Setting (P198)	257
Result Location	258
Routing Table Information (P199)	258
Example	258
PakBus Settings (Options \| PakBus Settings)	259
Network	259
Beacon Intervals	259
Neighbor Filter	260
Allocate General Purpose File Memory	260
List of Tables	261

Match case Limit results 1 per page

SECTION 7.

MEASUREMENT PROGRAMMING EXAMPLES

7-3

02:

Do (P86)

Set Port 1 High

03:

Excitation with Delay (P22)

Ex Channel

Delay w/Ex (units = 0.01 sec)

Delay after Ex (units = 0.01

sec)

mV Excitation

04:

Volts (SE) (P1)

Reps

2500 mV Slow Range

SE Channel

Loc [

]

Mult

Offset

05:

Do (P86)

Set Port 1 Low

7.4

ANEMOMETER WITH

PHOTOCHOPPER OUTPUT

An anemometer with a photochopper

transducer produces a pulse output which is

measured by the CR510's Pulse Count

Instruction.

The Pulse Count Instruction with a

Configuration Code of 20, measures "high

frequency pulses", "discards data from

excessive intervals", and "outputs the reading

as a frequency" (Hz = pulses per second).

The

frequency output is the only output option that is

independent of the scan rate.

The anemometer used in this example is the R. M.

Young Model 12102D Cup Anemometer, with a 10

window chopper wheel.

The photochopper

circuitry is powered from the CR510 12 V supply;

AC power or back-up batteries should be used to

compensate for the increased current drain.

Wind speed is desired in meters per second

(m/s).

There is a pulse each time a window in

the chopper wheel, which revolves with the

cups, allows light to pass from the source to the

photoreceptor.

Because there are 10 windows

in the chopper wheel, there are 10 pulses per

revolution.

Thus, 1 revolution per minute (rpm)

is equal to 10 pulses per 60 seconds (1 minute)

or 6 rpm = 1 pulse per second (Hz).

The

manufacturer's calibration for relating wind

speed to rpm is:

Wind(m/s) =

(0.01632 m/s)/rpm

∗

Xrpm

0.2 m/s

The result of the Pulse Count Instruction

(Configuration Code = 20) is X pulses per sec.

(Hz).

The multiplier and offset to convert XHz to

meters per second are:

Wind (m/s) = (0.01632

m/s)/rpm x (6 rpm/Hz) x XHz + 0.2 m/s

Wind (m/s) =

(0.09792 m/s)/Hz x XHz + 0.2 m/s

PROGRAM

01:

Pulse (P3)

Reps

Pulse Input Channel

High Frequency, Output Hz

Loc [ WS_mph

]

.09792 Mult

Offset

CR510

FIGURE 7.4-1.

Wiring Diagram for Anemometer