## Saturday, October 16, 2021

### Swiss Micros DM41X: Applications

Swiss Micros DM41X: Applications

Swiss Micros DM41X Program:  Euclid Algorithm

Registers:

R01:  A

R02: B

R03:  C  (used)

Finds the GCD of A and B, where A and B are positive integers and A > B.

01 LBL^T EUCLID

02 ^T GCD A>B

03 AVIEW

04 PSE

05 ^T A?

06 PROMPT

07 STO 01

08 ^T B?

09 PROMPT

10 STO 02

11 LBL 00

12 RCL 01

13 ENTER

14 ENTER

15 RCL 02

16 /

17 LASTX

18 X<>Y

19 INT

20 *

21 -

22 STO 03

23 X=0?

24 GTO 01

25 RCL 02

26 STO 01

27 X<>Y

28 STO 02

29 GTO 00

30 LBL 01

31 ^T GCD=

32 ARCL 02

33 AVIEW

34 END

Examples:

A = 100, B = 20, GCD = 20

A = 78, B =24, GCD = 6

Swiss Micros DM41X Program: Fan Laws

The program will calculate RPM_new (Revolutions per Minute), SP_new (Static Pressure), and BHP_new (Brake Horsepower).

Inputs:

CFM_old:  Cubic Feet of Minute - old

CFM_new:  Cubic Feet of Minute - new

RPM_old:  Revolutions per Minute - old

SP_old:  Static Pressure - old

BHP_old:  Brake Horsepower - old

Outputs:

RPM_new

SP_new

BHP_new

01 LBL^T FANLAWS

02 CLA

03 ^T CFM.OLD?

04 PROMPT

05 STO 01

06 ^T CFM.NEW?

07 PROMPT

08 STO 02

09 X<>Y

10 /

11 STO 04

12 STO 06

13 ST* 06

14 STO 08

15 ST* 08

16 ST* 08

17 ^T RPM.OLD?

18 PROMPT

19 STO 03

20 ST* 04

21 ^T SP.OLD

22 PROMPT

23 STO 05

24 ST* 06

25 ^T BHP.OLD?

26 PROMPT

27 STO 07

28 ST* 08

29 ^T RPM.NEW=

30 ARCL 04

31 AVIEW

32 STOP

33 ^T SP.NEW=

34 ARCL 06

35 AVIEW

36 STOP

37 ^T BHP.NEW=

38 ARCL 08

39 AVIEW

40 END

Variables:

R01 = CFM.OLD

R02 = CFM.NEW

R03 = RPM.OLD

R04 = RPM.NEW

R05 = SP.OLD

R06 = SP.NEW

R07 = BHP.OLD

R08 = BHP.NEW

The program uses a lot of storage arithmetic.

Example

Inputs:

CFM.OLD:  1250 CFM

CFM.NEW: 1600 CFM

RPM.OLD:  840 RPM

SP.OLD: 4 in

BHP.OLD: 7 BHP

Results:

RPM.NEW: 1075.2 RPM

SP.NEW: 6.5536 in

BHP.OLD:  14.680064 BHP

Source:

Calculated Industries "Sheet Metal/HVAC Pro Calc User's Guide" 2021

Swiss Micros DM41X Program: Johnson-Nyquist Noise Analysis

Equations Used:

Power (in Watts):

P = kb * T * Δf

RMS Voltage (in Volts):

v_n = √(4 * R * kb * T * Δf) = √(4 * R * P)

Current (in Amps):

i_n = √((4 * T * kb * Δf / R) = v_n / R

Inputs:

T = temperature in Kelvin  (°C + 273.15)

Δf = bandwidth, difference of frequencies in Hz

R = resistance in ohms (Ω)

Constants:  Boltzmann's Constant

kb ≈ 1.380649 * 10^-23 J/K

Program:

01 LBL^T NOISE

02 ^T TEMP? <K>

03 PROMPT

04 ^T BANDWIDTH?

05 PROMPT

06 *

07 1.308649E-23

08 *

09 ^T POW=

10 ARCL X

11 AVIEW

12 STOP

13 ^T R?

14 PROMPT

15 *

16 LASTX

17 X<>Y

18 4

19 *

20 SQRT

21 ^T V=

22 ARCL X

23 AVIEW

24 STOP

25 X<>Y

26 /

27 ^T I=

28 ARCL X

29 AVIEW

30 END

Example:

Temperature:  299.68 K

Bandwidth:  10,500 Hz

Resistance:  1375 Ω

Results:

Power:  4.3444E-17 W

Volts:  4.8882E-7 V

Current:  3.5550E-10 A

"Johnson-Nyquist Noise" Wikipedia.  Retrieved February 15, 2015 https://en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise

Eddie

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