Aviation_Moving_Map_Display

The software simulates three 400 Hz resolver tranmitters and provides a reference sinewave. Present version drives three pairs of sine/cosine outputs, and an additional pair of sinewave outputs 180 degree apart as reference. Resolver simulation is controlled by serial commands, push buttons, and a rotary encoder. Console is accesed by USB at 115200 bps with a terminal program or the arduino IDE.

Doxygen project

There is a Doxygen project file to create additional documentation of the software and libraries used. this readme and the module pictures get included. The doygen html needs to be created by running doxywizard. the html is not included in this repositary.

Doxyfile

PWM

RC Filter

PWM frequency is set to 100kHz by dividing the pico clock (133 Mhz) by 1330

The output is then filtered to remove the individuel pulses leaving the mean voltage proportional to the PWM duty cycle.

calculation R=1k, C=100n, Cut-off frequency: fc = 1591.5Hz

400 Hz generation

The PWM output duty cycle is modified regularly triggered by a timer set to a rate equal to the desired output frequency (400Hz) divided by the number of samples in a single cycle (36 ), or 69.5 uS

Unfortunateley the timer rate has to be an integer when using the arduino and so 69 or 70 have to be used. other possabilities are shown below, note 20 samples give an accurate 400Hz at the expense of a slightly steppy resultaing waveform:

36 table entries,  === 36 samples per cycle
1E6Hz  / 400Hz / (36) = 69.444 uS timer interval
69 = 402.576 Hz
70 = 396.825 Hz

40 table entries,  === 40 samples per cycle
1E6Hz  / 400Hz / (40) = . uS timer interval
62 = 403.2 Hz
64 = 396.8 Hz

20 table entries,  === 20 samples per cycle
1E6Hz  / 400Hz / (20) = . uS timer interval
125 = 400.0 Hz

The choice of frequency and sample count is made by constants in the program code defining the sine table generation and timer duration.

The waveform amplitude is obtained by reading a sine lookup table generated at program start, modified amplitudes for the resolver angles are made using the library sin and cos functions, speed is not an issue here as these calculations are done in the main program loop - not in the timer function.

Synchronisation

The 400 Hz waveform generators can be synchronised to an external 400 Hz signal, the signal is applied to a zero crossing detector, the output of which rises to 3v3 whenever the input voltage rizes positive above 0v. The pico interrupt input needs to be set to trigger on the rising edge.

Photo shows 3.3 V output rising edge coincident with zero crossing of input 115 V~ 400 Hz, trailing edge is not well defined and unused.

Video shows input voltage being raised from 0 to 115 VAC 400Hz

Youtube ZCD

Improved Isolated ZC Schematic

Revised parts list:

Part	Value
Q1	BC639
Q2	BC639
OC1	4N33
R1	22k
C1	2.2F
ZD1	9V1
R2	100k
R3	470R
R4	2.2k

AND9282 - Mains Synchronization for PLC Modems

LCD / Encoder menu system

Item
Heading
N to S
Absolute
Fine
Medium
Coarse
Show Settings
Toggle Automatic
Reset Absolute
Stepsize
AutoDelay
Vout
Vref
Ref Phase
Coarse Offset
M Offset
F Offset

Serial commands (not implemented in present version)

Commads in form "fin 30 [cr]" to set fine output pair to represent angle of 30 degrees, similar commands med, and cou, for medium and coarse settings.

Command
fin	Fine angle
med	Medium angle
coa	Coarse angle
abs	Absolute index
rep	report current settings
step	index step
auto	enable automatic increment
del	delay mS between increments
amp	Output amplitude divider

rotation of the encoder adjusts the absolute value by plus or minus step
A non-zero value in automatic starts the automatic absolute change cycle
Press of button A starts the automatic map movement
Press of button B stops the automatic mape movement
Press of Encoder button resets absolute position value
disabled: (When changing from auto to manual the encoder value is updated to allow fine control.)

Modbus USB data read / write

Write absolute value

david@I7MINT:~/Documents/Ferranti_PMD$ mbpoll -m rtu -b115200 -a10 -t4   /dev/ttyACM0 1234
mbpoll 1.4-12 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright © 2015-2019 Pascal JEAN, https://github.com/epsilonrt/mbpoll
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'mbpoll -w' for details.

Protocol configuration: Modbus RTU
Slave configuration...: address = [10]
                        start reference = 1, count = 1
Communication.........: /dev/ttyACM0,     115200-8E1 
                        t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

Written 1 references.

Read absolute value

david@I7MINT:~/Documents/Ferranti_PMD$ mbpoll -1 -m rtu -b115200 -a10 -t4   /dev/ttyACM0 
mbpoll 1.4-12 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright © 2015-2019 Pascal JEAN, https://github.com/epsilonrt/mbpoll
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'mbpoll -w' for details.

Protocol configuration: Modbus RTU
Slave configuration...: address = [10]
                        start reference = 1, count = 1
Communication.........: /dev/ttyACM0,     115200-8E1 
                        t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave 10...
[1]: 	1234

read modbus info

david@I7MINT:~/Documents/Ferranti_PMD$ mbpoll -1 -m rtu -b115200 -a10 -t4 -u  /dev/ttyACM0 
mbpoll 1.4-12 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright © 2015-2019 Pascal JEAN, https://github.com/epsilonrt/mbpoll
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'mbpoll -w' for details.

Protocol configuration: Modbus RTU
Slave configuration...: address = 10, report slave id
Communication.........: /dev/ttyACM0,     115200-8E1 
                        t/o 1.00 s, poll rate 1000 ms
Length: 14
Id    : 0x00
Status: On
Data  : Ferranti_PMD

Status display with buttons

Arduino sketch

Pico2040 pin designations

GP Pin	Function
16	TFT DC
17	TFT CS
18	TFT SCLK
19	TFT MOSI
22	ENCODER IN1
21	ENCODER IN2
20	ENCODER SW
0	PWM 0
1	PWM 1
2	PWM 2
3	PWM 3
4	PWM 4
5	PWM 5
6	PWM 6
7	PWM 7
8	PWM 8
9	PWM 9
10	PWM 10
11	PWM 11
14	Sync OP
15	Trig IP

Amplifier interconnections

Channel	Res	PWM	GPIO	Amp	R-L	Pin
Fine	sin	0A	0	1	R	51
Fine	cos	0B	1	1	L	52
Fine	com	-	-	-	C	53
Medium	sin	1A	2	2	R	59
Medium	cos	1B	3	2	L	60
Medium	com	-	-	-	C	61
Coarse	sin	2A	4	3	R	64
Coarse	cos	2B	5	3	L	65
Coarse	com	-	-	-	C	66
Ref	-	3A	6	4	R	48?
Ref	+	3B	7	4	L	49?
Ref	com	-	-	-	C	47
Heading	sin	4A	8	5	R	43
Heading	cos	4B	9	5	L	44
Heading	com	-	-	-	C	45
N to S	sin	5A	10	6	R	54
N to S	cos	5B	11	6	L	55
N to S	com	-	-	-	C	56

Initial conditions

After reset the module starts at absolute position of 0
sin outputs are zero amplitude, cos outputs are +ve maximum
-ve ref output is positive going at start of trigger output
+ve ref output is negative going at start of trigger output
sync output pulse positive edge is coincident with star of positive going cos 0 output
sync pulse input triggers start of positive going +ve ref output, cos 0 outputs
as angles increase from 0 sin outputs start to increase in positive direction
as angles increade positice cos output decreases

Absolute transport position encoding

Approximate representation showing supposed overlap of resolver rotations.

Absolute	17	16	15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00
Fine											07	06	05	04	03	02	01	00
Medium						07	06	05	04	03	02	01	00
Coarse	07	06	05	04	03	02	01	00

Absolute to resolver conversion

const float ratio1 = 31.9;
const float ratio2 = ratio1*32.1;

void abs2res(long absolute, float *fine, float *medium, float *coarse)
{
        *coarse = (absolute / ratio2) - offset_coarse;
        *medium = fmod((absolute / ratio1), 360);
        *fine   = fmod( absolute          , 360);

}

Wiring

A 400Hz 24 VAC reference signal from the module power supply is attenuated and clipped before being fed into an input of the pico, this is used to synchronise the generated waveforms to the reference . The input is fed through 10K resistor with a diode to ground in parallel with a 1K restor.

The PWM outputs are fed through a RC filter to form the analogue resolver signals. each channel is red through a 1K resistor and has a 100nF capacator to ground.

The signal output level is chosen to avaoid output clipping in the audio amplifiers.

Each pair of resolver signals is fed to a dual LM1875 amlifier to drive the module inputs.

A reference 400Hz is availabe on a seventh channel (unused)

A Reference pulse output is available to trigger the oscilloscope.

representive LM1875 schematic

Video: Resolver 400Hz sine / cosine from PWM generator

Video: initial pico map move

Video resolver spinning xy display

Connections

66 pin 18B35P PMD connector

Amphenol Connector 201-220-jt_series.pdf

Note: Connections marked n/c have no wires connected to plug
Note: pins without comment have unknown purpose
Note: Alt pins are equivalent functions on RPMD module
Additional information supplied by Erik Baigar see: http://www.baigar.de/TornadoComputerUnit/TimeLine.html#20130205

Power requirements

115 V 400Hz 0.5 to 1.0 amp (depends on lamp brightness)
28 VDC <100 mA
12-0-12 V 400 Hz resolver reference signal
11 V 400 Hz resolver signals, two per channel, 5 channels
28 VDC relay inputs ( pin 42 needed to power on unit )
Pin 16 when fed with 28 volts sometimes causes high current draw - lamp change motor.
This seems to now be broken as some smoke came out from the rear - ok without pin 16 active.
complete unit can just be powered from my static inverter, about 8.5 amp DC input when lamp lit

Pin #	Alt #	Function	Note
?	1	-ve	DC Return
02	2	Neutral	400Hz Return
03	3	115VAC	400Hz Power
04
05
06		n/c
07		n/c
08		n/c
09	9	0V	Chassis
10	10		input DAY/NIGHT control
11
12		n/c
13		n/c
14		n/c
15
16		728k to -ve	+ve relay? ip
17
18
19		n/c
20		n/c
21
22		11R to 32	V prop to I lamp
23
24
25
26	4	+28V DC	DC Power
27	17	+28V DC	DC Power
28
29
30	30		input to RPMD inhibiting map drive
31
32	32	-ve	DC Return
33

Pin #	Alt #	Function	Note
34	34	12 v op	Scale switch-a
35	35	12 v op	Scale switch-b
36	36	12 v op	Function switch-a
37	37	12 v op	Function switch-b
38	38	12 v op	Function switch-c
39		n/c
40	40	235R to 41	STB Lamp when positive
41	41	235R to 40	NTH UP lamp when positive
42	42	+28V DC	Mains-on ip
43	43	a	Heading-a
44	44	b	Heading-b
45	45	common	Heading-com
46
47	47	0V	Reference common
48	48	+12V 400Hz	Reference
49	49	-12V 400Hz	Reference
50
51	51	a	Fine-a
52	52	b	Fine-b
53	53	common	Fine-com
54	54	a	N/S-a
55	55	b	N/S-b
56	56	common	N/S-com
57		n/c
58		n/c
59	59	a	Medium-a
60	60	b	Medium-b
61	61	common	Medium-com
62		n/c
63		n/c
64	64	X3 yellow	Coarse-a
65	65	X3 red	Coarse-b
66	66	X3 black	Coarse-com

pin#22 has 0 to -10v PWM like signal which is proportional to lamp brightness

Circuit boards

No5_AMPLIFIER_ERROR_YT.jpg	No6_DRIVER_LAMP_CHANGER.jpg	No7_AMPLIFIER_ERROR_X.jpg	No8_AMP._ELECTRONIC_CONTROL.jpg	No9_AMPLIFIER_EC_OUTPUT.jpg
Screen Realy_Board.jpg	Screen Rectifier_Board.jpg

boards photo

Screen module circuit boards

Note: Boards 10, 11, 12 not fitted

No	Name	Position
5	AMPLIFIER, ERROR (Y-Θ)	Bottom
6	DRIVER, LAMP CHANGER	Bottom
7	AMPLIFIER, ERROR X	Top
8	AMPLIFIER, ELECTRONIC CONTROL	Top
9	AMPLIFIER, EC (OUTPUT)	Side
n/a	Rectifier Board	Side
n/a	Relay Board	Side

Board connector layout looking into PCB connector


2	4	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40	42	44	46	48	50	52	54	56	58	60
1	3	5	7	9	11	13	15	17	19	21	23	25	27	29	31	33	35	37	39	41	43	45	47	49	51	53	55	57	59

Board pin functions

Pin #	Board 5	AMPLIFIER, ERROR (Y-Θ)
1, 2	+5 V
3, 4	0 V
31,32	Gnd?
37,38	-16 V
51,52	+16 V
57	12 VAC	400 Hz +Reference ext_p48
60	12 VAC	400 Hz -Reference ext_p49
?	0 VAC	400 Hz Ref Common ct&gnd

Front panel switches

Scale switch

Fn.	#34	#35
56-1	H	L
28-1/2	L	H
14-1/4	H	H

Function switch

Fn.	#36	#37	#38
off	L	L	L
N	H	L	L
TRK	L	L	L
DEC	H	H	L
e	L	H	H
f	L	L	H


2	4	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40	42	44	46	48	50	52	54	56	58	60
1	3	5	7	9	11	13	15	17	19	21	23	25	27	29	31	33	35	37	39	41	43	45	47	49	51	53	55	57	59


2	4	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40	42	44	46	48	50	52	54	56	58	60
1	3	5	7	9	11	13	15	17	19	21	23	25	27	29	31	33	35	37	39	41	43	45	47	49	51	53	55	57	59

DavidJRichards/Aviation_Moving_Map_Display