6
Data Communication via RS232- and USB-B interface
6.1 General Information
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The burette TitroLine
means of these two interfaces it is possible to operate several devices on one computer (PC) interface.
In addition to that, the TitroLine
connect a PC.
RS232-C-1 establishes the connection to a connected computer or to the previous device of the "Daisy Chain".
At the RS232-C-2 it is possible to connect additional devices (Daisy Chain Concept).
PIN assignment of the RS232-C interfaces:
6.2 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 RS232-C interface 1 of the first
devise in the chain by means of a RS232-C data cable, e.g. Type No. TZ 3097. With the additional RS232-C data
cable, Type No. TZ 3094, the RS232-C- interface 2 of the first device is connected with the RS232-C-interface 1
of the second device. At interface 2 of the second device it is possible to connect an additional device.
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The TitroLine
7500 KF can also be connected via USB cable TZ 3840 (type A (M) – type B (M), 1.8m). It is also
possible to connect the TitroLine
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.
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 5.3.
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The burette TitroLine
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
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TitroLine
7500 KF did before.
All information (data strings) which arrive at interface 2 of the burette TitroLine
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.
6.3 Instruction Set for RS-Communication
The commands consist of three parts: Address
Every command must be completed with the ASCII - sign <CR> and <LF> (Carriage Return and Line Feed).
Only if the respective action has ended the answers will be returned to the computer.
Example:
The command to dose 12.5 ml shall be sent to the burette TitroLine® 7500 KF with the address 2.
The command consists of the characters: 02DA12.5<CR LF>
In detail:
02
DA
12.5
<CR LF> = Control character as command end
7500 KF has two serial RS232-C interfaces to communicate data with other devices. By
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7500 KF also has an alternatively USB-B interface, which can only be used to
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7500 KF via USB cable TZ 3840 (type A (M) --- USB type B (M), 1.8 m) to a
7500 KF receives commands from a PC at the interface 1 (USB- B) if the computer knows
Command
Variable, if necessary
and end of command
= Device address
= Dosage command with filling and zero points of the display
= Volume in ml to be dosed
PIN-No. Meaning / Description
1
T x D Data output
2
R x D Data input
3
Digital mass
two-digit aa, e.g.: 01
e.g.: DA
e.g.: 14
<CR> <LF>
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7500 KF will immediately be send
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