Hello list:
I have three A&D EJ-3000 scales that I want to simultaneously acquire data
from every 1 minute over 24-hr periods. All scales have a USB interface.
I've started working through the pyusb tutorial, but before I confuse
myself any further, I thought I'd ask if what I want to do is even
possible? Tech support at A&D told me that retrieving weight data from the
scales automatically (i.e. without pushing the print button on the scales)
could not be done with USB because the interface was uni-directional.
Instead, they suggested that I switch to RS-232. Is this true, and if so
why?
I printed the configuration of the scale after installing pyusb and
starting the tutorial.
CONFIGURATION 1: 20 mA ===================================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x2 Configuration
wTotalLength : 0x2d (45 bytes)
bNumInterfaces : 0x1
bConfigurationValue : 0x1
iConfiguration : 0x0
bmAttributes : 0x80 Bus Powered
bMaxPower : 0xa (20 mA)
INTERFACE 0: Human Interface Device ====================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x0
bAlternateSetting : 0x0
bNumEndpoints : 0x2
bInterfaceClass : 0x3 Human Interface Device
bInterfaceSubClass : 0x0
bInterfaceProtocol : 0x1
iInterface : 0x0
ENDPOINT 0x81: Interrupt IN ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x81 IN
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x4
ENDPOINT 0x2: Interrupt OUT ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x2 OUT
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x4
Any guidance would be greatly appreciated.
Mark
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