""" Demonstrates how to stream using the eStream functions. """ from datetime import datetime import sys from labjack import ljm MAX_REQUESTS = 25 # 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","AIN120","AIN121","AIN122","AIN123","AIN124","AIN125","AIN126","AIN127","AIN48","AIN49", "AIN50","AIN51", "AIN52", "AIN53","AIN54", "AIN55", "AIN56", "AIN57", "AIN58", "AIN59", "AIN60", "AIN61", "AIN62", "AIN63", "AIN64", "AIN65", "AIN66", "AIN67", "AIN68", "AIN69", "AIN70", "AIN71", "AIN72", "AIN73", "AIN74", "AIN75", "AIN76", "AIN77", "AIN78", "AIN79", "AIN80", "AIN81", "AIN82", "AIN83", "AIN84", "AIN85", "AIN86", "AIN87", "AIN88", "AIN89", "AIN90", "AIN91", "AIN92", "AIN93", "AIN94", "AIN95", "AIN96", "AIN97", "AIN98", "AIN99" ] # Scan list names to stream numAddresses = len(aScanListNames) print "numAddresses: ", numAddresses aScanList = ljm.namesToAddresses(numAddresses, aScanListNames)[0] scanRate = 1000 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", "AIN_ALL_RANGE", "STREAM_SETTLING_US", "STREAM_RESOLUTION_INDEX"] aValues = [ljm.constants.GND, 10.0, 8, 1] # 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 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)