Nov-16-2018, 06:32 PM
I want to read in the values of AINO - AIN11 and output them into different rows so the 1st row would read in the scans AINO - AIN11 then move to the next row and read in the values again and so on until the end of the loop (6000 scans currently). Right now it just separates each value and doesn't discern from scan 1 or 2 etc. I want to separate them out to differentiate between AINO-AIN1, AIN2-AIN3 and so forth. Once I separate them out I want to create 6 columns which produce the end value of AINO-AIN1, AIN2-AIN3, AIN4-AIN5, AIN6-AIN7, AIN8-AIN9, AIN10-AIN11. I'm rather new to coding/python and we're using labjack to read in the values to the file. Any help or idea would be appreciated.
from datetime import datetime
import sys
from labjack import ljm
file = open ("LabjackT7.txt", "w")
MAX_REQUESTS = 1 # The number of eStreamRead calls that will be performed.
# Open first found LabJack
handle = ljm.openS("ANY", "ANY", "ANY") # Any device, Any connection, Any identifier
#handle = ljm.openS("T7", "ANY", "ANY") # T7 device, Any connection, Any identifier
#handle = ljm.openS("T4", "ANY", "ANY") # T4 device, Any connection, Any identifier
#handle = ljm.open(ljm.constants.dtANY, ljm.constants.ctANY, "ANY") # Any device, Any connection, Any identifier
info = ljm.getHandleInfo(handle)
print("Opened a LabJack with Device type: %i, Connection type: %i,\n"
"Serial number: %i, IP address: %s, Port: %i,\nMax bytes per MB: %i" %
(info[0], info[1], info[2], ljm.numberToIP(info[3]), info[4], info[5]))
deviceType = info[0]
# Stream Configuration
aScanListNames = ["AIN0", "AIN1", "AIN2", "AIN3", "AIN4", "AIN5", "AIN6", "AIN7", "AIN8", "AIN9", "AIN10", "AIN11"] # Scan list names to stream
numAddresses = len(aScanListNames)
aScanList = ljm.namesToAddresses(numAddresses, aScanListNames)[0]
scanRate = 10000
scansPerRead = int(scanRate / 2)
try:
# When streaming, negative channels and ranges can be configured for
# individual analog inputs, but the stream has only one settling time and
# resolution.
if deviceType == ljm.constants.dtT4:
# LabJack T4 configuration
# AIN0 and AIN1 ranges are +/-10 V, stream settling is 0 (default) and
# stream resolution index is 0 (default).
aNames = ["AIN0_RANGE", "AIN1_RANGE", "STREAM_SETTLING_US",
"STREAM_RESOLUTION_INDEX"]
aValues = [10.0, 10.0, 0, 0]
else:
# LabJack T7 and other devices configuration
# Ensure triggered stream is disabled.
ljm.eWriteName(handle, "STREAM_TRIGGER_INDEX", 0)
# Enabling internally-clocked stream.
ljm.eWriteName(handle, "STREAM_CLOCK_SOURCE", 0)
# All negative channels are single-ended, AIN0 and AIN1 ranges are
# +/-10 V, stream settling is 0 (default) and stream resolution index
# is 0 (default).
aNames = ["AIN_ALL_NEGATIVE_CH", "AIN0_RANGE", "AIN1_RANGE",
"STREAM_SETTLING_US", "STREAM_RESOLUTION_INDEX"]
aValues = [ljm.constants.GND, 10.0, 10.0, 0, 0]
# Write the analog inputs' negative channels (when applicable), ranges,
# stream settling time and stream resolution configuration.
numFrames = len(aNames)
ljm.eWriteNames(handle, numFrames, aNames, aValues)
# Configure and start stream
scanRate = ljm.eStreamStart(handle, scansPerRead, numAddresses, aScanList, scanRate)
print("\nStream started with a scan rate of %0.0f Hz." % scanRate)
print("\nPerforming %i stream reads." % MAX_REQUESTS)
start = datetime.now()
totScans = 0
totSkip = 0 # Total skipped samples
i = 1
while i <= MAX_REQUESTS:
ret = ljm.eStreamRead(handle)
aData = ret[0]
scans = len(aData) / numAddresses
totScans += scans
# Count the skipped samples which are indicated by -9999 values. Missed
# samples occur after a device's stream buffer overflows and are
# reported after auto-recover mode ends.
curSkip = aData.count(-9999.0)
totSkip += curSkip
print("\neStreamRead %i" % i)
ainStr = ""
for j in range(0, numAddresses):
ainStr += "%s = %0.5f, " % (aScanListNames[j], aData[j])
print(" 1st scan out of %i: %s" % (scans, ainStr))
print(" Scans Skipped = %0.0f, Scan Backlogs: Device = %i, LJM = "
"%i" % (curSkip/numAddresses, ret[1], ret[2]))
i += 1
#Data Stream string of last eStreamRead
file.write('%s' % aData)
file.close()
end = datetime.now()
print("\nTotal scans = %i" % (totScans))
tt = (end - start).seconds + float((end - start).microseconds) / 1000000
print("Time taken = %f seconds" % (tt))
print("LJM Scan Rate = %f scans/second" % (scanRate))
print("Timed Scan Rate = %f scans/second" % (totScans / tt))
print("Timed Sample Rate = %f samples/second" % (totScans * numAddresses / tt))
print("Skipped scans = %0.0f" % (totSkip / numAddresses))
except ljm.LJMError:
ljme = sys.exc_info()[1]
print(ljme)
except Exception:
e = sys.exc_info()[1]
print(e)
try:
print("\nStop Stream")
ljm.eStreamStop(handle)
except ljm.LJMError:
ljme = sys.exc_info()[1]
print(ljme)
except Exception:
e = sys.exc_info()[1]
print(e)
# Close handle
ljm.close(handle)Output:Opened a LabJack with Device type: 7, Connection type: 4,
Serial number: 470017729, IP address: 10.17.1.151, Port: 502,
Max bytes per MB: 500
Stream started with a scan rate of 10000 Hz.
Performing 1 stream reads.
eStreamRead 1
1st scan out of 5000: AIN0 = 2.45952, AIN1 = 2.44658, AIN2 = 2.43301, AIN3 = 2.43238, AIN4 = 2.46110, AIN5 = 2.46678, AIN6 = 2.41281, AIN7 = 2.40587, AIN8 = 2.42291, AIN9 = 2.43175, AIN10 = 2.45795, AIN11 = 2.44532,
Scans Skipped = 2502, Scan Backlogs: Device = 31, LJM = 247
Total scans = 5000
Time taken = 3.132619 seconds
LJM Scan Rate = 10000.000000 scans/second
Timed Scan Rate = 1596.108560 scans/second
Timed Sample Rate = 19153.302716 samples/second
Skipped scans = 2502
Stop Stream