Manual

SR50 Sonic Ranging Sensor

The following instructions set the sensor enable line high long enough for the

SR50 to detect it, then set it low.

1: Set Port (P20)

1: 1 Set High

2: 1 Port Number

2: Excitation with Delay (P22)

1: 1 Ex Chan

2: 1 Delay w/Ex (units = 0.01 sec)

3: 0000 Delay After Ex (units = 0.01 sec)

4: 0.0 mV Excitation

3: Set Port (P20)

1: 0 Set Low

2: 1 Port Number

The P3 instruction counts the pulse train being transmitted from the SR50.

Distance-to-surface will automatically be reset to 0.00 after the distance is

calculated and stored for later processing and output.

4: Pulse (P3)

1: 1 Reps

2: 1 Pulse Input Chan

3: 00 Config Option

4: 21 Loc [ Dis2Surf ]

5: -.0025 Mult

6: 0.0 Offset

Measure air temperature and convert to degrees Kelvin. This example assumes

air temperature is being measured with Campbell Scientific’s Model 107

probe.

5: Temp 107 Probe (P11)

1: 1 Reps

2: 1 In Chan

3: 1 Excite all reps w/Exchan 1

4: 22 Loc [ T_Kelvin ]

5: 1 Mult

6: 273.15 Offset

Compute the air temperature compensation factor and correct the distance-to-

surface for air temperature (see formula 1).

6: Z=F (P30)

1: 273.15 F

2: 23 Z Loc [ 273_15 ]

7: Z=X/Y (P38)

1: 22 X Loc [ T_Kelvin ]

2: 23 Y Loc [ 273_15 ]

3: 24 Z Loc [ ATempComp ]