User Manual

34 Quatech QTM-8524 Manual
4. Configuration
4.1 RS-232 or RS-485 Configuration
QTM-8524 modules can be configured for either RS-232 or RS-485 serial
communication. This setting is selected using jumper seven on the module
as shown:
(7)
RS-232
RS-485
When connecting the QTM-8524 directly to a PC, RS-232 mode must be
used. (See section 2.5.1 for instructions on how to wire the QTM-8524 for
connection to a PC.). To implement a QTM-8000 Series network using a
single pair of QTM-8524 modules, the upstream module must be configured
as RS-232 and connected to the PC’s serial port. The downstream modules
should be configured for RS-485 in order to communicate with the QTM-
8000 Series data acquisition and signal conditioning modules. When using
multiple pairs of QTM-8524 modules in conjunction with the QTM-8520
converter module, both QTM-8524s should be configured for RS-485. (See
section 2.5.2.1 for instructions on how to wire the QTM-8524 for connection
to a QTM-8000 Series network.)
4.2 Half-Duplex and Full-Duplex Operation
QTM-8524 modules can operate in both Full-Duplex and Half-Duplex modes.
In Half Duplex mode communication can take place in only one direction at
a time. Each device can communicate information in a single direction only-
- transmit or receive. If more than one module transmits data at the same
instant, then the data on the bus will be corrupted and therefore invalid. In
3.3.3 RF Safety
The QTM-8524 has been classified by the FCC as a §15.247 Spread Spectrum
Mobile Transmitter. The antennas selected for use with this transmitter were cho-
sen to provide optimum safety when installed properly. Please reference Sections
3.3.3 and 3.3.2 of this manual before installing the antennas. Keep in mind that
mounting the antennas higher yields a twofold benefit: better reception and less
RF exposure to people in the general vicinity. According to FCC requirements for
MPE compliance, the antennas must be installed to provide a minimum distance of
20cm from all persons under normal use.