Campbell Scientific SDM-CVO4 4-Channel Current/Voltage Output Module - Manual (Page 24)

SDM-CVO4 4-Channel Current/Voltage Output Module
; As we have four channels to output, we will first copy the
; current readings with P54, block move, in a block of four
; input locations to hold the scaled outputs
9: Block Move (P54)
1: 4
No. of Values
2: 1 First Source Loc [ WindSpeed ]
3: 1 Source Step
4: 5 First Destination Loc [ ScldOut_1 ]
5: 1 Destination Step
; Then apply the scaling with one Instruction P53
; The readings are scaled -5000 to +5000, i.e. to
; cover the full scale range which would equate to
; 0 - 10,000 mV in voltage mode or 0-20 mA in
; current mode.
; Windspeed to cover the range 0-100 m/s
; Wind direction to cover 0-360 degrees
; Temperature -25 to +50 degrees C
; Radiation 0 - 1000 m^2/s
10: Scaling Array (A*Loc+B) (P53)
1: 5
Start Loc [ ScldOut_1 ]
2: 100 A1 ; WS multiplier
3: -5000 B1 ; WS Offset
4: 27.7778 A2
5: -5000
B2
6: 133.333 A3
7: -1666.67 B3
8: 10
A4
9: -5000 B4
; Now update the SDM-CVO4 with the information
; for the four channels
11: SDM-AO4 (P103)
1: 4
Reps
2: 30 SDM Address
3: 5 Loc [ ScldOut_1 ]
6.5.2 Restricted Range Current Output Modes (4-20 mA)
When driving a system that requires a restricted current range then the full-
scale range is reduced accordingly. In the case of 4-20 mA devices the
maximum range is 8000 units and the minimum value should be scaled to
-3000 and prevented from going below this level.
The following partial program could be used in place of the last two
instructions in the example above.
20