[Error 24: Invalid Sampling Rate]

14 minutes ago, JRys said:

Could you jump into InstaCal and check how channel 0 is configured and how the Data Rate filter property is set? It must be set to 3750 to sample at 550 samples per second. Page 16 in the user manual discusses throughput rates.

Another thing to keep in mind is that the USB-2416-4AO is a device that remembers how it is set even after power is removed. Not all MCC devices do this. So, if a colleague sets it for temperature and you try to use it for voltage, it will generate an error until it is reconfigured with InstaCal.

Oh interesting!  We should be calling ul.ignore_instacal() before setting up the DAQ (which I forgot to include in my stub code - my bad on that! The full code is located below). Changing Ch23's rate to 3750 in InstaCal did resolve it, despite the call to ul.ignore_instacal(). Thanks for the help!

 

from __future__ import absolute_import, division, print_function
from _ctypes import POINTER, addressof, sizeof
from ctypes import c_double, cast

import math
import time
import numpy as np
import matplotlib.pyplot as plt
import scipy.signal as signal

from builtins import *  # @UnusedWildImport

from mcculw import ul
from mcculw.enums import ULRange, InfoType, BoardInfo, AiChanType, AnalogInputMode, ScanOptions, FunctionType, InterfaceType, Status, DigitalPortType
from examples.console import util
from examples.props.ao import AnalogOutputProps
from examples.props.ai import AnalogInputProps
from mcculw.ul import ULError

try:
    ul.ignore_instacal()
    device = ul.get_daq_device_inventory(InterfaceType.ANY)[0]
    board_num = 0
    ul.create_daq_device(board_num, device)
    
    dout_low_chan = 0
    dout_high_chan = 0
    dout_total_count = 10240
    dout_rate = 1000
    dout_ao_range = ULRange.BIP10VOLTS
    dout_memhandle = ul.win_buf_alloc(10240)
    dout_scan_options = (ScanOptions.BACKGROUND | ScanOptions.CONTINUOUS)

    low_chan = 0
    high_chan = 1
    ul_buffer_count = 3300
    rate = 550
    ai_range = ULRange.BIP10VOLTS
    memhandle = ul.scaled_win_buf_alloc(3300)
    scan_options = (ScanOptions.BLOCKIO | ScanOptions.BACKGROUND | ScanOptions.CONTINUOUS | ScanOptions.SCALEDATA)


    chan_array = [0,23]
    gain_array = [ULRange.BIP10VOLTS,ULRange.BIP10VOLTS]

    ul.a_out_scan(board_num, dout_low_chan, dout_high_chan, dout_total_count, dout_rate, dout_ao_range, dout_memhandle, dout_scan_options)
    ul.a_load_queue(board_num, chan_array, gain_array, len(chan_array))
    
    ul.a_in_scan(board_num, low_chan, high_chan, ul_buffer_count, rate, ai_range, memhandle, scan_options)
finally:
    ul.stop_background(board_num, FunctionType.AOFUNCTION)
    ul.stop_background(board_num, FunctionType.AIFUNCTION)
    ul.win_buf_free(dout_memhandle)
    ul.win_buf_free(memhandle)

 

[Error 24: Invalid Sampling Rate]

I am using a USB-2416-4AO with AI-EXP32 expansion board and am getting an Error 24: Invalid Sampling Rate. This code works properly using on other DAQ / PC pairs so there must be something wrong with my setup. The DAQ is using the latest firmware (2.03). A colleague recalls seeing something similar when the DAQ came back from calibration and was still in some "calibration" configuration rather than its normal state but does not recall the details - could this be the cause here? Any other suggestions?

 

board_num = 0
dout_low_chan = 0
dout_high_chan = 0
dout_total_count = 10240
dout_rate = 1000
dout_ao_range = ULRange.BIP10VOLTS
dout_memhandle = ul.win_buf_alloc(10240)
dout_scan_options = (ScanOptions.BACKGROUND | ScanOptions.CONTINUOUS)

low_chan = 0
high_chan = 1
ul_buffer_count = 3300
rate = 550
ai_range = ULRange.BIP10VOLTS
memhandle = ul.scaled_win_buf_alloc(3300)
scan_options = (ScanOptions.BLOCKIO | ScanOptions.BACKGROUND | ScanOptions.CONTINUOUS | ScanOptions.SCALEDATA)

chan_array = [0,23]
gain_array = [ULRange.BIP10VOLTS,ULRange.BIP10VOLTS]

ul.a_out_scan(board_num, dout_low_chan, dout_high_chan, dout_total_count, dout_rate, dout_ao_range, dout_memhandle, dout_scan_options)
ul.a_load_queue(board_num, chan_array, gain_array, len(chan_array))
ul.a_in_scan(board_num, low_chan, high_chan, ul_buffer_count, rate, ai_range, memhandle, scan_options) # Running this line results in Error 24