
ASCII PROTOCOL
The Transmission format is: 1 START bit, 8 DATA bits, NO
parity bit and 1 STOP bit.
FORMAT of MESSAGE TO BESENT FROM MASTER
A message sent from the master device to the instrument must
be composed of the following sequence
of ASCII characters:
* D d C C
X ........................... X
CR
One " * " byte [ASCII 42] of start of message.
Two address bytes (from 00 to 99).
One or two ASCII characters corresponding to the desired
command according to the Functions TABLE (Add
endum
A.1).
In case that the command request for a modification of
parameters, the new value shall be transmitted with one
byte of sign ( + [ASCII 43] or
-
[ASCII 45] ) followed by a
block of N ASCII characters (depending on model), including
the decimal
point.
One " CR " [ASCII 13] character of end of message.
FORMAT of MESSAGE FROM INSTRUMENT
The data sent from the instrument as a response to a
data request type command from the master device is
the following:
SP
X ........................... X
CR
One byte of blank space [ASCII 32].
One text (requested values) consisting of a byte of
sign (+ [ASCII 43] or
-
[ASCII 45] ) followed by a
block of N ASC
II characters (depending on model)
including the decimal point.
One " CR " byte [ASCII 13] of end of message.
If the command belongs to orders or changing
parameters , the instruments gives no response.
1.2.
DESCRIPTION OF OPERATION
Three communication modes are provided; The ASCII mode utilizes an easy to use protocol, compatible with several models
of DITEL instruments. The ISO mode, according to the ISO 1745 standard, permits a more safe commun
ication in noisy
environments since the data transfer is verified at the transmission and reception ends. In addition can be used a third
protocol: MODBUS RTU (see manual on www.ditel.es)
As it can be seen in the Functions TABLE (Addendum A.1), the ASCII
protocol uses 1 or 2 bytes commands depending of the
command type while the ISO 1745 protocol forces the use of two bytes per command.
ASCII PROTOCOL
The Transmission format is:
1 START bit, 8 DATA bits, NO
parity bit and 1 STOP bit.
FORMAT of MESSAGE TO BESENT FROM MASTER
A message sent from the master device to the instrument must
be composed of the following sequence of ASCII characters:
* D d C C
X ....................
....... X
CR
One " * " byte [ASCII 42] of start of message.
Two address bytes (from 00 to 99).
One or two ASCII characters corresponding to the desired
command according to the Functions TABLE (Addendum
A.1).
In case that the command request for a modi
fication of
parameters, the new value shall be transmitted with one
byte of sign ( + [ASCII 43] or
-
[ASCII 45] ) followed by a
block of N ASCII characters (depending on model), including
the decimal point.
One " CR " [ASCII 13] character of end of messag
e.
FORMAT of MESSAGE FROM INSTRUMENT
The data sent from the instrument as a response to a
data
request type command from the master device is
the following:
SP
X ........................... X
CR
One byte of blank space [ASCII 32].
One text (requested values) consisting of a byte of
sign (+ [ASCII 43] or
-
[ASCII 45] ) followed by a
block of N
ASCII characters (depending on model)
including the decimal point.
One " CR " byte [ASCII 13] of end of message.
If the command belongs to orders or changing
parameters , the instruments gives no response.
1.2.
DESCRIPTION OF OPERATION
Three communication modes are provided; The ASCII mode utilizes an easy to use protocol, compatible with several models
of DITEL instruments. The ISO mode, according to the ISO 1745 standard, p
ermits a more safe communication in noisy
environments since the data transfer is verified at the transmission and reception ends. In addition can be used a third
protocol: MODBUS RTU (see manual on www.ditel.es)
As it can be seen in the Functions TABLE
(Addendum A.1), the ASCII protocol uses 1 or 2 bytes commands depending of the
command type while the ISO 1745 protocol forces the use of two bytes per command.