SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES

09:

P

103SDM-A04

01:

4

Reps

02:

30

Address

03:5 Loc WS output

10:

P92

If time is

01:

0

minutes into a

02:

60

minute interval

03:

10

Set high Flag 0 (output)

11:

P69

Wind Vector

01:

1

Rep

02:180 Samples per sub-interval

03:00 Polar Sensor/(S ,D1, SD1)

04:1 Wind Speed/East Loc WS

05:2 Wind Direction/North Loc

0-360 WD

12:

P71

Average

01:

2

Reps

02:

3

Loc Ta

13:P End Table 1

8.7CONVERTING 0-360 WIND DIRECTION OUTPUT TO 0-540 FOR STRIP CHART

If 0-360 degree wind direction is output to a strip chart the discontinuity at 0/360 will cause the pen to jump back and forth full scale when the winds are varying from the north. In the days of strip charts this was solved with a 0-540 degree pot on the wind vane (direction changes from 540 to 180 and from 0 to 360 so the pen only jumps once when the wind is out of the north or south).

When faced with the necessity of strip chart output (see previous example), the following algorithm can be used to change a 0-360 degree input to 0-540. (If you have a 0-540 pot, it can be used with the CR10 since the Wind Vector Instruction, 69, will work with this output.)

To change 0-360 degrees to the 0-540 degrees, 360 degrees must sometimes be added to the reading when it is in the range of 0 to 180. The following algorithm does this by assuming that if the previous reading was less than 270, the vane has shifted through 180 degrees and does not need to be altered. If the previous 0-540 reading was greater than 270, 360 degrees is added.

This example is written as a subroutine which is used by the previous example to output an analog voltage to a strip chart.

Input Location Labels:

2:0-360 WD 6:0-540 out 10:0-540 WD

*3 Table 3 Subroutines

01:P85 Beginning of Subroutine

01:1 Subroutine Number

02:

P89

If X<=>F

01:10 X Loc 0-540 WD

02:

3

>=

03:

270

F

04:

30

Then Do

03:

P86

Do

01:11 Set high Flag 1

04:

P94

Else

05:

P86

Do

01:21 Set low Flag 1

06:

P95

End

07:

P31

Z=X

01:2 X Loc 0-360 WD

02:10 Z Loc [:0-540 WD]

08:

P89

If X<=>F

01:10 X Loc 0-540 WD

02:

4

<

03:

180

F

04:

30

Then Do

09:

P91

If Flag/Port

01:

11

Do if flag 1 is high

02:

30

Then Do

10:

P34

Z=X+F

01:10 X Loc 0-540 WD

02: 360

F

03:10 Z Loc [:0-540 WD]

11:

P31

Z=X

01:10 X Loc 0-540 WD

02:

6

Z Loc [:0-540 out]

12:

P95

End

13:

P95

End

8-8