Usb Interface; Physical Connection; Hardware Support; Installing The Usb Driver - Lakeshore 335 User Manual

100 c 6: Computer Interface Operation
HAPTER

6.3 USB Interface

6.3.1 Physical
Connection
6.3.2 Hardware
Support
6.3.3 Installing the USB
Driver
Model 335 Temperature Controller
The Model 335 USB interface provides a convenient way to connect to most modern
computers, as a USB interface is provided on nearly all new PCs as of the writing of
this manual. The USB interface is implemented as a virtual serial com port connec-
tion. This implementation provides a simple migration path for modifying existing
RS-232 based remote interface software. It also provides a simpler means of commu-
nicating than a standard USB implementation.
The Model 335 has a B-type USB connector on the rear panel. This is the standard
connector used on USB peripheral devices, and it allows the common USB A-type to
B-type cable to be used to connect the Model 335 to a host PC. The pin assignments
for A-type and B-type connectors are shown in section 8.10. The maximum length of a
USB cable, as defined by the USB 2.0 standard, is 5 m (16.4 ft). This length can be
extended using USB hubs every 5 m (16.4 ft) up to 5 times, for a maximum total
length of 30 m (98.4 ft).
The USB interface emulates an RS-232 serial port at a fixed 57,600 baud rate, but
with the physical connections of a USB. This programming interface requires a cer-
tain configuration to communicate properly with the Model 335. The proper configu-
ration parameters are listed in TABLE 6-5.
Baud rate 57,600
Data bits 7
Start bits
1
Stop bits 1
Parity Odd
Flow control None
Handshaking None
TABLE 6-5 Host com port
configuration
The USB hardware connection uses the full speed (12,000,000 bits/s) profile of the
USB 2.0 standard; however, since the interface uses a virtual serial com port at a fixed
data rate, the data throughput is still limited to a baud rate of 57,600 bits/s.
The Model 335 USB driver has been made available through Windows® Update. This
is the recommended method for installing the driver, as it will ensure that you always
have the latest version of the driver installed. If you are unable to install the driver
from Windows® Update, refer to section 6.3.3.3 to install the driver from the web or
from the disc provided with the Model 335.
These procedures assume that you are logged into a user account that has adminis-
trator privileges.
6.3.3.1 Installing the Driver From Windows® Update in Windows Vista® or Windows 7
1. Connect the USB cable from the Model 335 to the computer.
2. Turn on the Model 335.
3. When the Found New Hardware wizard appears, select Locate and install driver
software (recommended).
4. If User Account Control(UAC) is enabled, a UAC dialog box may appear asking if
you want to continue. Click Continue.
5. The Found New Hardware wizard should automatically connect to Windows®
Update and install the drivers.