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5.3 Device address and daisy chaining of several
TITRONIC
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Piston Burettes
— Daisy Chain Concept —
In order to enable you to individually address several devices in a chain, each of the devices must have an
address of its own. To achieve this, one has first of all to use an RS-232-C data cable, e.g. no. TZ 3096
type, to establish a connection between the computer and the RS-232-C socket 1 (interface 1) of the first
device in the chain. Using another RS-232-C data cable, no. TZ 3094 type, the RS-232-C socket 2 (inter-
face 2) of the first device is connected to interface 1 of the second device,
&
Fig. 7. Additional devices
can then be connected to the interface 2 of the second device.
The address always consists of 2 characters: e.g. address 1 of the two <0> and <1> ASCII characters. The
address can be set from
00
to
15
, i.e. there are 16 possibilities. Please ensure that the addresses of the
devices in the chain are different. If a device is addressed using its address, the device will work off this
command without sending it to another device. The response to the computer or titrator also receives the
own address. You can change the address from the <<Parameter RS 232>> menu using the <F4> key,
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“Setting the data transfer parameters”. The ex-factory set address of the TITRONIC
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Piston
Burette is 01.
The TITRONIC
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Piston Burette will receive commands from a computer or titrators at inter-
face
1
, if the latter carries this address, and this interface will also be used to return its response. If the ad-
dress of the incoming commands does not match their device address, the entire command will be for-
warded
at
interface
2
. This interface 2 is connected to interface 1 of another TITRONIC
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Piston Burette.
This piston burette, in turn, will now check the address and will respond to this command just like the first
burette. Any information (data strings) arriving at the interface 2 of the TITRONIC
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Piston
Burette will be output at interface 1 to the computer or titrator immediately. This means that the computer
will in any case receive the information of all burettes. In practice it is possible to connect up to 16 devices
to a computer (PC) interface.
As has been mentioned above, the proper functioning of the daisy chain concept requires that each piston
burette has an address consisting of 2 digits in a row.
5.4 Command list for RS communication
The commands are made up of the following 3 elements:
Address 2-digit aa,
e.g.: 01
Command
e.g.: BP
Variable, if required
e.g.: 14
and end of command
<CR> <LF>
Each
command has to end on the <CR> and <LF> (Carriage Return and Linefeed) ASCII characters. All
responses will only be returned to the computer upon completion of the respective action.
Example:
It is intended to send to the piston burette with the address 5 the command to dose 12.5 ml,
with preceding filling of the cylinder and zero reset of the display.
The command consists of the following characters: 05DO12.5<CR LF>
Here is:
05
= Device address
DO
= Command for dosing with filling
12.5
= Volume to be dosed in ml
<CR LF> = Control character for end of volume
All TITRONIC
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Piston Burettes will, irrespective of their address, respond to address 99. The
99AA1 command automatically attributes to the individual devices the address from 01 to nn. So it is e.g.
possible that addresses starting from 05 are output. In this case all devices will then respond with their new
address. If a command is preceded by AB, all the TITRONIC
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Piston Burettes will work off the
command and report back automatically. This means that one command can fill all burettes. The corre-
sponding command is: 01ABBF<CR LF>.
