7 Data Communication via RS-232- and USB-B interface
7.1 General Information
The burette TITRONIC
®
300 has two serial RS-232-C interfaces to communicate data with other devices. By
means of these two interfaces it is possible to operate several devices on one computer (PC) interface.
In addition to that, the TITRONIC
®
300 also has an alternatively USB-B interface, which can only be used to
connect a PC.
RS-232-C-1 establishes the connection to a connected computer or to the previous device of the “Daisy Chain”.
At the RS-232-C-2 it is possible to connect additional devices (Daisy Chain Concept).
PIN assignment of the RS-232-C interfaces:
7.2 Chaining multiple devices — „Daisy Chain Concept“
In order to activate several devices in a chain individually, each device must have an own device address. For
this it is at first necessary to establish a connection from the computer to the RS-232-C interface 1 of the first
devise in the chain by means of a RS-232-C data cable, e.g. Type No. TZ 3097. With the additional RS-232-C
data cable, Type No. TZ 3094, the RS-232-C- interface 2 of the first device is connected with the RS-232-C-
interface 1 of the second device. At interface 2 of the second device it is possible to connect an additional device.
The TITRONIC
®
300 can also be connected via USB cable TZ 3480 (type A (M) – type B (M), 1.8m). It is also
possible to connect the TITRONIC
®
300 via a mini USB to a USB interface of a PC. To accomplish this
connection, a driver has to be installed on the PC. Then the USB-B interface takes over the function of the
RS232-1 interface. Please contact SI Analytics for acquiring the software.
The address always consists of two characters: e.g. address 1 of the two ASCII- characters <0> and <1>. The
addresses can be set from 00 to 15, i.e. 16 possibilities. It must be ensured that the devices in a chain have
different addresses. If a device is addressed with its address, this device will process this command without
sending it to another device. The reply to the computer has also an own address. The addresses are allocated as
described in Chapter 5.2.
The burette TITRONIC
®
300 receives commands from a PC at the interface 1 (USB- B) if the computer knows the
address. It also sends the answer via this interface. If the address of the incoming command does not match the
device address, the complete command will be forwarded to interface 2. Interface 2 is connected to interface 1 of
another device. This device checks the address as well and reacts to the command as the first TITRONIC
®
300
did before.
All information (data strings) which arrive at interface 2 of the burette TITRONIC
®
300 will immediately be send to
the computer via interface 1 (or USB-B interface). Thus, the computer receives the data of all devices. In practice
it is possible to connect up to 16 devices to one computer- (PC-) interface.
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