Controlling The Lt51 - H Heuer Instruments UMDT51A User Manual

Controlling the LT51

Control of the LT51 by a PC is possible over the USB connection, which appears
as a COM port on the PC.
The LT51View PC application also provides an ability to interface to the LT51 via
commands read from a text file. Please see the documentation for the LT51View
program for a description of this interface and the specific commands.
The USB virtual COM port needs to be configured with the following settings for
successful communication:

9600 Baud, 8-bit data, 1 Stop Bit, No parity.
Commands from the PC to LT51 always consist of 5 bytes:

<CMD><D1><D2><D3><D4>
Upon successful reception of the 5-byte command, the LT51 will respond by
returning an ACK(0x99) byte OR data byte(s).
NOTE: The LT51 will wait until it receives 5 bytes. This can lead to
synchronisation issues if an incorrect number of bytes is transmitted for
a command. To ensure the PC-LT51 control link is correctly
synchronised, the PC can repeatedly transmit the ACK byte (0x99) until
the LT51 responds with an ACK (0x99). At this point the PC-LT51 is
synchronised and ready to accept a new command.
Command
CONFIGSETTING
CONFIGTXLEVEL
CONFIGTXFREQ
CONFIGCENTREFREQ
READDATA1
READDATA2
READDATA3
LT51 User Manual
CMD D1
0xAD Config
0xAE LevHi
0xAF Freq1
0xB0 Freq1
0xB1 xx
0xB2 xx
0xB3 xx
D2 D3
Value xx
LevLo xx
Freq2 Freq3
Freq2 Freq3
xx xx
xx xx
xx xx
PC Interface
D4
xx
xx
Freq4
Freq4
xx
xx
xx
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