User Manual

Remote Operation
The USB interface allows the instrument to be controlled using serial communications via a
computer’s USB port.
The instrument is supplied with a disk containing drivers for various versions of Windows. Any
driver updates are available via the TTi website, www.tti-test.com. The disk also contains a text
file with information and details of the software installation procedure.
The remote command format and the remote commands themselves are detailed later in this
section. The remote commands of the earlier TTi TF830 Universal Counter can also be used on
the TF930, allowing existing programs to be used. However, the TF930 has no address
capability and those commands associated with ARC (Addressable RS232 Control) will be
accepted but ignored.
Remote/Local Operation
At power−on the instrument will be in the local state; in this state all keyboard operations are
possible. When the instrument receives a command the remote state will be entered and the Rem
annunciator will show in the display. In this state the keyboard is locked out, except for the Local
(RESET) and OPERATE keys, and remote commands only will be processed.
The instrument may be returned to the local state by a long press of the Local (RESET) key; the
Rem annunciator will go off. However, the effect of this action will remain only until the instrument
receives another character from the interface, when the remote state will once again be entered.
Sending the LOCAL command also exits the remote state.
USB Interface
The USB interface of this instrument is implemented using a USB to UART device which then
communicates with a UART inside the main processor. Once the device drivers are installed on a
PC the device will appear to be a standard COM port as if it were inside the PC. This port can
then be accessed by Windows applications in exactly the same way as a standard port.
If it is anticipated that more than one TF930 might be connected to the same PC it is
recommended that the drivers be copied first to a suitable location on the hard disc and then
installed from there when the first unit is attached. The operating system can then subsequently
find the drivers without requiring the CD.
Installation of the interface drivers is achieved by connecting the instrument to a PC via a
standard USB cable. The Windows’ plug and play functions should automatically recognise the
addition of new hardware attached to the USB interface and, if this is the first time the connection
has been made, prompt for the location of a suitable driver. Two layers of driver are required and
the standard Windows prompts will appear twice. Provided that these prompts are followed
correctly Windows will install the appropriate drivers and establish a COM port within the PC. The
number of the new COM port will depend upon the number of previously allocated COM ports
within that PC.
Note: If the plug and play function reports that a later version of the driver is already installed,
keep the later version; the TF930 will operate satisfactorily with the later version.
A unique code embedded in each instrument ensures that it will receive the same COM port
number each time it is attached to the PC, irrespective of which physical USB port it is connected
to. A different unit will prompt again for installation of the drivers the first time it is attached, and
will receive a different COM port number.
The operating parameters of the COM port must be set to match the internal requirements of the
instrument: baud rate 115200, 8 bits, no parity. The default values are set in the Properties page
in Device Manager, but many communications programs override the default settings and each
will need to be correctly configured.
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