Quatech QTM-8524 Manual
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Note 1:
In Half Duplex operation, the channel selection jumper setting need
not be used.
Note 2:
For a multi-point application, the network must be configured for
Half Duplex operation. Thus, QTM-8000 Series data acquisition and signal
conditioning modules can not be used in this network type.
4.3 Synchronous & Asynchronous Communication
The QTM-8524 can be jumper configured for two modes of data communica-
tion-- synchronous and asynchronous. (This selection is made using jumper
6, see
Figure 2.4 for a diagram of QTM-8524 jumper settings.)
In synchronous
mode, the QTM-8524 uses an internal system clock to synchronize the data
bits. When the QTM-8524 is configured for synchronous communication,
the PC or serial communication device to which it is attached must send
data in the format specified below:
1 START BIT, 8 DATA BITS, NO PARITY, 1 STOP BIT
Whether receiving or transmitting, all QTM-8524 modules configured for
synchronous communication can only process data in the above format.
When configured for asynchronous mode, QTM-8524 modules can process
signals in any data format. To prevent data distortion, the sampling rate and
data rate in asynchronous networks should be limited to 32 kS/s and 14.4
kbps respectively.
Note:
QTM-8524 modules configured for asynchronous mode must also be
configured for RS-232 communication. Thus, asynchronous mode can not
be used when the QTM-8524 is integrated into a QTM-8000 Series data ac-
quisition and signal conditioning network.
Half duplex mode, all modules must have the same baudrate and frequency
configuration and all modules must be jumper configured for slave. (See
Figure 2.4 for a diagram of QTM-8524 jumper settings.)
In Full Duplex systems, transmission and reception can occur simultaneously.
For example, device A can send information to device B while at the same
time receiving data from device C. In order for the QTM-8524 modules to
function in Full Duplex mode, the module connected to the PC or to the QTM-
8520 must be jumper configured for master, and the downstream QTM-8524
must be jumper configured for slave mode. Both modules must be set to the
same baudrate, frequency and channel. When using QTM-8524 modules
with QTM-8000 Series I/O modules, Full Duplex mode must be used.
