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skycraper3

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Posts posted by skycraper3

    MCC 128 & MCC 172 frequency question

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Hello,

    I'm using MCC 128 and MCC 172 for data acquisition and noticed frequency is not exact.

    My application is continuous acquisition and split data at every hour reached, timestamps of these file is increasing constantly like
    00:00:00.data
    01:00:00.data
    02:00:01.data
    03:00:01.data
    04:00:02.data...
    , every file has exactly same size because it just appends data from "a_in_scan_read(frequency, timeout)" 3600 times to binary.

    This application running on 2048 Hz, and I know MCC128 has cannot achieve 2048 Hz (it shows 2047.8... Hz from a_in_scan_actual_rate()), but in MCC172 shows 2048 Hz but it drift about 0.02~0.07 seconds per hour. Of course data is continuous.

    These RPis has GPS source, it syncs time from GPS every minute.

    Is it normal or have to handle in code?

     

    Suffering noise from MCC 128 and MCC 172

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Hello, our team using MCC128 and MCC172 DAQs but suffering buzzing noise when use 3.3V MEMS microphones.

    This problem occurred few months ago, but we didn't got any clues on this problem.

    3.3V microphones using VCC and GND from raspberry pi 3 itself, audio output is directly connected in High channels like CH0+ or CH0H.

    Microphones are tested properly and all works fine but when we starts recording on MCC128 or MCC172, we got buzzing sound during normal signals.

    We tried few MEMS micrphones and also tried RaspberryPi 4 but results are not so different.

    Can we get any solution or advice on this problem?

    Attached images are noise plot and spectrogram, we using 4 channels, 2048 Hz sampling rates. Y axis on plot is Voltage.

    plot.thumb.png.a8081d88ef6ce31973ad33dcf5258238.png

     

    plot2.thumb.png.e75fa1a19deb8492b50c5dfcb3e432d1.png

    spectrogram.thumb.png.865676a4c6bd5875395e6447feea31e7.png

    Periodical spikes when using MCC 172 and so on

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello, sorry for late reply,

    I received new 2x MCC172 board today (nw, planned for another raspberrypi), so just tested.

    Below plot from IEPE disabled and no microphones connected condition, 1 minute record at 2048hz frequency.
    That noise still occurs every one minute, I'm guessing caused by raspberrypi that damaged or emitting something, is it possible?
    With proper IEPE sensors, it works nicely.

    newboard_no_mic_no_iepe.thumb.png.33b10f35df33a290c5886db4b3d86f88.png

     

    On 12/1/2022 at 6:56 AM, Fausto said:

    Hello @skycraper3.

    From your previous post, the red data represents ch1 on the master board, while the green data represents ch0 on the slave board.  Is this correct?  Did you try swapping cables and IEPE sensors between the channels and boards?

    And yes, its correct. Tried swap cables and change boards.

    Periodical spikes when using MCC 172 and so on

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Thanks for reply, Fausto.

    Ok, I change my question,

    I connected 4x PCB IEPE Microphone in 2x MCC 172, starts recording with IEPE enabled, i got this, (its OK, of course)

    n5.thumb.png.78a1dd0e8334f81ab2366840c339624d.png

     

    But when IEPE disabled with same setting, I got this one,

    n4.thumb.png.03e3446b645d76ae9141ecd85b82ee4a.png

    You can see red and green noise, that is same noise as I posted yesterday.

    Is it normal? If so, what is reason of that situation?

    In this question, I'm on RaspberryPi 4B (5.15.76-v7l), no other HAT boards attached.

    Periodical spikes when using MCC 172 and so on

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Hello,

    I'm using MCC 172s but having problem now, spike noise.

     

    noise1.thumb.png.1b90b993fdac7f9483c9984c4f6e3d01.png

    noise2.thumb.png.c2045dd118f66190b4bfb15e25b5e37b.png

    noise1_2.thumb.png.0143cd4c7eae57c094f26399616259ce.png

    when 4 channels connected:

    blue : master board, ch0
    red : master board, ch1
    green : slave board, ch0
    purple : slave board, ch1 (IEPE microphone connected, others are non IEPE MICs)

    n3.thumb.png.f33e38170bba56a34321b79a9b0efcea.png

     

    These spikes occur pretty periodically, about every 1 minute when recording signal. (regardless of IEPE status)

    Can I get any help about this issue? I'm using 2x MCC172 (4Ch input), some channels spike bigger and some others not.

    It seems OK when connects IEPE powered microphone with preamp but when nothing connected or using non-IEPE microphone, these noise can be noticed easily.

    I'm using 5V, 3A power supply. Any helps or advices would be much appreciated.

     

    Additional question, can I use mcc172_reset() in library when making DAQ boards literally 'reset' likes when RPi board freshly turns on and nothing initialized. I just want to release GPIOs that DAQ HATs holding when initialize completed (or records)

     

    Thanks, Lee.

    MCC172 HAT with additional 3rd party SPI interface HAT board

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello, I'm using 2 x MCC172 HAT currently, and want to use additional HAT for RS-485 serial communication.

    So, purchased https://www.waveshare.com/wiki/2-CH_RS485_HAT this one that using NXP SC16IS752 chip.

    My raspberry pi has now 3 HATs, RaspberryPi 4B + MCC172 + MCC172 + RS485 HAT.

    At the first, I just activated NXP chip driver in /boot/config.txt and seems work.
    But when starts MCC 172 data acquisition during tty capture, tty displayed garbage data (guess binary data from MCC172).

    I searched interface specifications of MCC 172 and found from datasheet,

    Quote

    Raspberry Pi™ GPIO pins used GPIO 8, 9, 10, 11 (SPI interface)
    ID_SD, ID_SC (ID EEPROM) GPIO 12, 13, 26, (Board address)
    GPIO 5, 6, 19, 16, 20 (clock / trigger sharing, reset, IRQ)
    Data interface type SPI slave device, CE0 chip select
    SPI mode 1
    SPI clock rate 18 MHz

    SO I tried added lines on /boot/config.txt 

    dtoverlay=spi1-2cs,cs1_pin=17
dtoverlay=sc16is752-spi1,int_pin=24

    and changed device tree overlay to CE1 chip select likes below, 

    /dts-v1/;
/plugin/;

/ {
	compatible = "brcm,bcm2835";

	fragment@0 {
		target = <&gpio>;
		__overlay__ {
			spi1_pins: spi1_pins {
				brcm,pins = <19 20 21>;
				brcm,function = <3>; /* alt4 */
			};

			spi1_cs_pins: spi1_cs_pins {
				brcm,pins = <17>;
				brcm,function = <1>; /* output */
			};
		};
	};

	fragment@1 {
		target = <&spi1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			pinctrl-names = "default";
			pinctrl-0 = <&spi1_pins &spi1_cs_pins>;
			cs-gpios = <&gpio 17 1>;
			status = "okay";

			sc16is752: sc16is752@1 {
				compatible = "nxp,sc16is752";
				reg = <1>; /* CE1 */
				clocks = <&sc16is752_clk>;
				interrupt-parent = <&gpio>;
				interrupts = <23 2>; /* IRQ_TYPE_EDGE_FALLING */
				gpio-controller;
				#gpio-cells = <2>;
				spi-max-frequency = <4000000>;
			};
		};
	};

	fragment@2 {
		target = <&aux>;
		__overlay__ {
			status = "okay";
		};
	};

	fragment@3 {
		target-path = "/";
		__overlay__ {
			sc16is752_clk: sc16is752_spi1_0_clk {
				compatible = "fixed-clock";
				#clock-cells = <0>;
				clock-frequency = <14745600>;
			};
		};
	};

	__overrides__ {
		int_pin = <&sc16is752>,"interrupts:0";
		xtal = <&sc16is752_clk>,"clock-frequency:0";
	};
};

    Unfortunately, I got error, below is dmesg results,

    Quote

    spi-bcm2835aux fe215080.spi: cs1 >= max 1
    spi_master spi1: spi_device register error /soc/spi@7e215080/sc16is752@1
    spi_master spi1: Failed to create SPI device for /soc/spi@7e215080/sc16is752@1
    spi-bcm2835aux fe215080.spi: cs1 >= max 1
    spi_master spi1: spi_device register error /soc/spi@7e215080/spidev@1
    spi_master spi1: Failed to create SPI device for /soc/spi@7e215080/spidev@1

    I'm not good at kernel, message seems raspberrypi-side problem, but I cannot find MCC172 overlay in boot folder.
    Also hard to find reference on web, can I get any help?

    MCC 172 Synchronous scan question

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Thanks for reply, I ran modified code but no difference 😅 (added mcc172_iepe_config_write() because I'm using IEPE mic)

    These are my setup,

     

    latest Raspberry Pi OS 32bit, SPI, I2C On, using external ports - Keyboard/Mouse/HDMI

    2 MCC 172 HATs, jumper installed A0 on slave HAT (upper board) - followed instruction (Installing the DAQ HAT board — MCC DAQ HAT Library 1.0.0 documentation)

    IEPE sensor input with BNC splitter at master HAT (under board) CH0 and slave HAT (upper board) CH0, BNC splitter likes this
    (Actually signal without splitter seems have difference so I decided to gives same input to DAQs)

    10-32 to BNC were connected with provided connectors and same length of each cables

    MCC 172 Synchronous scan question

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Hello,

    Tried changing clock configuring order of HATs and I even tried with C examples, but still 2~4 samples difference was detected. I'm just guessing there were only external trigger examples because these hardware issue :/

    Attached file is code that i modified running option and skipping trigger routine for test.

    Sincerely,

    Lee

    multi_hat_synchronous_scan.c

    MCC 172 Synchronous scan question

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hi again,

    I changed codes to call start slave board first, but result is not so different just Master DAQ is faster than Slave DAQ.

    Codes like: 

    master_hat.iepe_config_write()
slave_hat.iepe_config_write()

slave_hat.a_in_clock_config_write()
master_hat.a_in_clock_config_write()

synced = False
while not synced:
	(_, _, synced) = master_hat.a_in_clock_config_read() # for get "synced" (i also tried this for slave_hat)

slave_hat.a_in_scan_start() # with option Continuous
master_hat.a_in_scan_start() # with option Continuous

read_and_display_data_loop()

hats.a_in_scan_stop()
hats.a_in_scan_cleanup()

    When I call a_in_clock_config_read() during read function, both HATs saying 'synchronized=True'... I'm confused now.

    MCC 172 Synchronous scan question

    in Data Acquisition (DAQ) & Data Logging

    Posted · Edited by skycraper3

    Hello,

     

    I have 2 MCC 172 DAQs and would like to synchronous scan now, but there are only examples with external triggers. So I modified existing example like attached code, and test without external trigger. But it seem DAQs have different start time (Figure 1). I used BNC distributor so blue and green graph on Figure 1 have same input. Additionally, blue graph is data from device #0 (Master).

    Is there any way to start DAQs simultaneously without external trigger or just code is wrong?

     

    Cheers,

    Lee

     

     

    Figure_1.png

    multi_hat_synchronous_scan_test.py

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