background image

CS615 WATER CONTENT REFLECTOMETER

9

;delay loop to wait remainder of execution
;interval once AM416 is clocked, and one
;complete execution interval for precise
;pulse count interval.

7:  Beginning of Loop (P87)

1:

1

Delay

2:

2

Loop Count

8:  End (P95) ;end of delay loop

9:  Pulse (P3) ;read CS615s

1:

3

Reps

2:

1

Pulse Input Channel

3:

21

Low Level AC, Output Hz

4:

1

Loc [ kHz#1     ]

5:

.001

Mult

6:

0.0

Offset

;convert frequencies to period.  0.001 multiplier
;converts kHz to milliseconds.

10:  Z=1/X (P42)

1:

1

X Loc [ kHz#1     ]

2:

4

Z Loc [ period#1  ]

11:  Z=1/X (P42)

1:

2

X Loc [ kHz#2     ]

2:

5

Z Loc [ period#2  ]

12:  Z=1/X (P42)

1:

3

X Loc [ kHz#3     ]

2:

6

Z Loc [ period#3  ]

13:  Polynomial (P55) ;apply calibration

1:

3

Reps

2:

4

X Loc [ period#1  ]

3:

7--

F(X) Loc [ water#1   ]

4:

-.187

C0

5:

.037

C1

6:

.335

C2

7:

0.0

C3

8:

0.0

C4

9:

0.0

C5

14:  End (P95)

15:  Do (P86) ;set CS615 enable low

1:

53

Set Port 3 Low

16:  Do (P86) ;set AM416 reset low

1:

51

Set Port 1 Low

17:  Do (P86)

1:

10

Set Output Flag High

18:  Sample (P70)

1:

48

Reps

2:

7

Loc [ water#1   ]

19:  End (P95)

End Program

10.4  SAMPLE PROGRAM 4

Program using the Period Averaging Instruction
(P27) of CR10 datalogger and AM416
multiplexer to read 48 CS615 probes

CAUTION:

1.

The probe rods of the CS615 are
essentially antennae which transmit and
receive radio waves.  Interference can
occur when enabled probes are in close
proximity and electrical conductivity of
the measured medium is high.
Generally, interference is not a problem
when the distance between enabled
probes is greater than 20 cm.  It may be
necessary to configure probe
placement and multiplexer connection
to alleviate probe interaction.

;{CR10}
;
*Table 1 Program

01:

1.0

Execution Interval (seconds)

;Once an Hour, Read Probes

1:  If time is (P92)

1:

0

Minutes into a

2:

60

Minute Interval

3:

30

Then Do

; enable multiplexer

2:  Do (P86)

1:

41

Set Port 1 High

; turn on port that enables 615s

3:  Do (P86)

1:

43

Set Port 3 High

;Multiplexer loop

4:  Beginning of Loop (P87)

1:

0

Delay

2:

16

Loop Count

; clock multiplexer

5:  Do (P86)

1:

72

Pulse Port 2

Summary of Contents for CS615

Page 1: ...CS615 WATER CONTENT REFLECTOMETER INSTRUCTION MANUAL version 8221 07 REVISION 10 96 COPYRIGHT c 1995 1996 CAMPBELL SCIENTIFIC INC ...

Page 2: ... merchantability or fitness for a particular purpose CAMPBELL SCIENTIFIC INC is not liable for special indirect incidental or consequential damages Products may not be returned without prior authorization To obtain a Returned Materials Authorization RMA contact CAMPBELL SCIENTIFIC INC phone 435 753 2342 After an applications engineer determines the nature of the problem an RMA number will be issue...

Page 3: ...IONS 4 1 Accuracy 2 4 2 Resolution 2 4 3 Operating Range 2 5 INSTALLATION 5 1 Orientation 3 5 2 Potential Problems with Improper Insertion 3 6 WIRING 4 7 DATALOGGER INSTRUCTIONS 7 1 Introduction 4 7 2 Pulse Count 4 7 3 Period Measurement 5 8 MAINTENANCE 5 9 CALIBRATION 9 1 General 5 10 SAMPLE PROGRAMS 6 10 1 Sample Program 1 7 10 2 Sample Program 2 7 10 3 Sample Program 3 8 10 4 Sample Program 4 9...

Page 4: ... of two stainless steel rods connected to a printed circuit board A shielded four conductor cable is connected to the circuit board to supply power enable the probe and monitor the pulse output The circuit board is encapsulated in epoxy High speed electronic components on the circuit board are configured as a bistable multivibrator The output of the multivibrator is connected to the probe rods whi...

Page 5: ...content but it is also affected by electrical conductivity Free ions in soil solution provide electrical conduction paths which result in attenuation of the signal applied to the waveguides This attenuation both reduces the amplitude of the high frequency signal on the probe rods and affects the shape of the oscillating signal The attenuation reduces oscillation frequency at a given water content ...

Page 6: ...s were performed at various water contents and over the temperature range from 10 C to 30 C The calibration information presented in Section 9 is for a temperature of 20 C The following equation can be used to interpolate the temperature coefficient for a range of volumetric water content θv values Coeftemperature v v 3 46 10 0 019 0 045 4 2 θ θ To apply this correction the following equation can ...

Page 7: ... in the calibration for water content The Pulse Count instruction of a CR10 CR500 21X or CR7 dataloggers can be used with the CS615 output connected to a pulse count channel The Period Measurement instruction of the CR10 or CR500 can be used with the CS615 output connected to a single ended analog channel 7 2 PULSE COUNT It is important to understand the event sequence during the Instruction 3 Pul...

Page 8: ...uction to enable the CS615 and these instructions can take a significant amount of time to execute During the second time through the Loop Instruction the pulse counters see the CS615 output for the full execution interval At the end of this interval the accumulators transfer to RAM and are reset When the program execution then moves to the Pulse Count Instruction P3 the value in RAM is converted ...

Page 9: ...fect on the calibration but the magnitude is dependent on the clay type electrical conductivity dS m 1 calibration 1 0 θ τ τ τ v 0187 0 037 0 335 2 1 8 θ τ τ τ v 0 207 0 097 0 288 2 3 0 θ τ τ τ v 0 298 0 361 0 096 2 θv is the volumetric water content on a fraction basis i e 0 20 is 20 volumetric water content τ is the CS615 output period in milliseconds 9 2 CALIBRATION FOR A SPECIFIC SOIL The cali...

Page 10: ...nvert period to water content 1 1 Reps 2 1 X Loc 615period 3 2 F X Loc 615water 4 0 187 C0 5 0 037 C1 6 0 335 C2 7 0 0 C3 8 0 0 C4 9 0 0 C5 6 Do P86 1 10 Set Output Flag High 7 Real Time P77 1 0220 Day Hour Minute 8 Sample P70 1 2 Reps 2 1 Loc 615period 9 End P95 End Program 10 2 SAMPLE PROGRAM 2 Simple program using the Pulse Count Instruction P3 of a CR10 CR500 or 21X datalogger to read a single...

Page 11: ...ion to volumetric water content is invoked using the Polynomial Instruction The water content values are written to output storage Attention to program structure when using the Pulse Count Instruction with sensors that are periodically enabled is necessary to ensure accurate results See Section 7 2 for a detailed description of the Pulse Count Instruction CAUTION 1 The probe rods of the CS615 are ...

Page 12: ...w 17 Do P86 1 10 Set Output Flag High 18 Sample P70 1 48 Reps 2 7 Loc water 1 19 End P95 End Program 10 4 SAMPLE PROGRAM 4 Program using the Period Averaging Instruction P27 of CR10 datalogger and AM416 multiplexer to read 48 CS615 probes CAUTION 1 The probe rods of the CS615 are essentially antennae which transmit and receive radio waves Interference can occur when enabled probes are in close pro...

Page 13: ...hannel 4 10 No of Cycles 5 5 Timeout units 0 01 seconds 6 1 Loc msec 1 7 001 Mult 8 0 0 Offset 8 End P95 set ports enabling mux and probes low 9 Do P86 1 51 Set Port 1 Low 10 Do P86 1 53 Set Port 3 Low apply calibration 11 Polynomial P55 1 48 Reps 2 1 X Loc Period 1 3 49 F X Loc WatCont 1 4 0 187 C0 5 0 037 C1 6 0 335 C2 7 0 0 C3 8 0 0 C4 9 0 0 C5 12 Do P86 1 10 Set Output Flag High 13 Real Time P...

Page 14: ...C3 P1 P2 P3 21x Using Pulse Count Reset Clock H1 L1 H2 L2 H1 L1 H2 L2 H1 L1 H2 L2 H1 L1 H2 L2 1 2 16 enable signal enable signal enable signal enable signal enable signal enable signal enable signal 48 6 5 4 3 2 1 CR10 or 21X AM416 CS615 SE1 SE2 SE3 CR10 Using Period Measurement signal 46 signal 47 signal 48 SE Single Ended Input Channel ...

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