UGPlus Gread() 函数不断返回 b'\n'

如何解决UGPlus Gread() 函数不断返回 b'\n'

我正在尝试编写一个 Python 脚本来通过 HPIB/GPIB 控制 HP3478A 万用表。我使用的是 LQ 电子 UGPlus USB 转 GPIB 控制器：

http://www.lqelectronics.com/Support/USBUG/USBUG_support.html

http://www.lqelectronics.com/Support/USBUG/download.html

我的脚本如下：

import ctypes
import time
from time import sleep
import os

if os.path.exists("C:\Program Files (x86)") == True:
    UGPluslib = ctypes.CDLL("C:\\Program Files (x86)\\LQElectronics\\UGPlus\\UGPlusAPI\\LQUGPlus_c.dll")
else:
    print("Error: LQ UGPlus USB-to-GPIB connector library not found")

#defining restypes from UGPlus dynamic library
UGPluslib.Gwrite.restype = ctypes.c_int
UGPluslib.Gread.restype = ctypes.c_char_p
UGPluslib.Gquery.restype = ctypes.c_char_p

UGPluslib.Gbread.restype = ctypes.c_char_p

GPIBaddress = ctypes.c_int(23)

#NOTE: Multimeter responds to text display commands if given in hex!
#      P   R   A   I   S   E       T   H   E
#b"D2\x50\x52\x41\x49\x53\x45\x20\x54\x48\x45\x0D"
#      O   M   N   I   S   S   I   A   H
#b"D2\x4f\x4d\x4e\x49\x53\x53\x49\x41\x48\x0D"
GPIBtext1 = ctypes.c_char_p(b"D2\x50\x52\x41\x49\x53\x45\x20\x54\x48\x45\x0D")
GPIBtext2 = ctypes.c_char_p(b"D2\x4f\x4d\x4e\x49\x53\x53\x49\x41\x48\x0D")
GPIBtext_nothing = ctypes.c_char_p(b"")
GPIBReturnFromTextCommand = ctypes.c_char_p(b"D1")

GPIBcmd_set300OhmRes = ctypes.c_char_p(b"F3 R4 T1 \x0D\x0A")
GPIBcmd_set300OhmRes_hold = ctypes.c_char_p(b"F3 R3 T4 \x0D\x0A")
GPIBcmd_startMeasurment = ctypes.c_char_p(b"T1 \x0D\x0A")

def praiseTheMachineGod():
    UGPluslib.Gwrite(GPIBaddress,GPIBtext1.value)
    sleep(1.5)
    UGPluslib.Gwrite(GPIBaddress,GPIBtext2.value)
    sleep(2.0)
    UGPluslib.Gwrite(GPIBaddress,GPIBReturnFromTextCommand.value)
    sleep(3.0)

#leads to '\n' being read which indicates error
def takeResistanceMeasurement_1():
    ans = input("take resistance measurement? y/n: ")
    if ans == 'y':
        print("Taking measurement: ")
        if not(UGPluslib.Gwrite(GPIBaddress,GPIBcmd_set300OhmRes)):
            sleep(1)
            reading = UGPluslib.Gread(GPIBaddress)
            print(reading)
        else:
            print("Error taking measurement")
    else:
        print("Aborting")

#leads to '\n' being read which indicates error
def takeResistanceMeasurement_2():
    ans = input("take resistance measurement? y/n: ")
    if ans == 'y':
        print("Taking measurement: ")
        reading = UGPluslib.Gquery(GPIBaddress,GPIBcmd_set300OhmRes)
        print(reading)
    else:
        print("Aborting")

#leads to '\n' being read which indicates error and an 'invalid data read' mssg being displayed from LQ
def takeResistanceMeasurement_3():
    ans = input("take resistance measurement? y/n: ")
    if ans == 'y':
        print("Taking measurement: ")
        UGPluslib.Gwrite(GPIBaddress,GPIBcmd_set300OhmRes.value)
        sleep(0.8)
        reading = UGPluslib.Gbread(GPIBaddress)
        print(reading)
    else:
        print("Aborting")

#leads to '\n' being read which indicates error and a 'time out' mssg being displayed from LQ
def takeResistanceMeasurement_4():
    ans = input("take resistance measurement? y/n: ")
    if ans == 'y':
        print("Taking measurement: ")
        if not(UGPluslib.Gwrite(GPIBaddress,GPIBcmd_set300OhmRes_hold)):
            sleep(1)
            if not(UGPluslib.Gwrite(GPIBaddress,GPIBcmd_startMeasurment)):
                reading = UGPluslib.Gread(GPIBaddress)
                print(reading)
        else:
            print("Error taking measurement")
    else:
        print("Aborting")

print("Running Command Sequence...")
praiseTheMachineGod()
takeResistanceMeasurement_1()

现在 HP3478A 可以很好地接收来自该脚本的命令，运行任一 takeResistanceMeasurement_x() 函数将其置于所需状态。这意味着 LQUGPlus_c.dll 中的 Gwrite() 函数可以工作。

然而，任何 takeResistanceMeasurement_x() 函数中的 Gread() 函数总是返回一个 b'\n'，根据文档，它表示一个错误。我无法弄清楚为什么会这样。我将在此处提供 UGPlus USB-to-GPIB 连接器和 HP3478A 的所有相关文档的链接，以便任何勇敢的人都能看一看：

https://www.manualslib.com/manual/1004577/Hp-3478a.html

http://www.lqelectronics.com/Support/USBUG/UGPlus/UGPlus%20USB%20to%20GPIB%20Controller%20User%20Manual.pdf

我已经广泛地查看了文档，但也许我错过了一些东西。 如果有人对为什么 Gread() 函数在这里行为不端有任何见解，我将不胜感激

编辑：

可能应该提供更多详细信息。我使用的是 64 位 Windows 10 操作系统