HD51.3D…
- 32 -
V2.0
8
RS485 ASCII PROPRIETARY MODE
In RS485 ASCII proprietary mode, the instrument sends the acquired measurements only if
requested by the PC.
To use this mode, you must connect to a RS485 or RS422 serial port. Communication parame-
ters should be set in the PC or data logger as follows:
•
Baud rate:
same as the setting in the instrument (default = 115200)
•
Data bits:
8
•
Parity:
same as the setting in the instrument (default = None)
•
Stop bits:
same as the setting in the instrument (default = 2)
The instrument is requested to send measurements by generating a
Break Signal
(*)
on the serial
line for at least 2
ms, and then sending the following command, consisting of 4 ASCII characters:
M<Address><x>G
with <Address> = address of the instrument measurements are requested to
<x> = any ASCII character, except G
E
XAMPLE
To ask the instrument with address 2 to send the acquired measurements, do the following:
1)
Break
Signal
for at least 2
ms;
2) Send command:
M2aG
.
The instrument answers with the following string:
IIIIM<Address>I&<M1><M2>….<Mn><SP>&AAAM<Address><CS><CR>
with <Address> = address of the instrument sending measurements
<M1><M2>….<Mn> = values of the first, second,…., nth measurement
<SP> = space
<CS> = checksum (hex value of the 8-bit checksum of all the preceding characters)
<CR> = ASCII character Carriage Return
Fields <M1><M2>….<Mn> consist of 8 characters each. Measurement values are justified
right; spaces can be added to the left margin of the values to obtain the 8 character length re-
quested by the fields. The sequence of the measurement values <M1><M2>….<Mn> is con-
figurable (command
CU1Dcccccc
, see chapter 6
).
E
XAMPLE
Supposing that the instrument with address 2 measures the following values (the measuring
unit is not considered, being not output by the instrument): M1=2.23, M2=-28.34, M3=0.34,
M4=28.30, M5=359.3, M6=-1.3, the instrument reply takes the following form:
IIIIM2I& 2.23 -28.34 0.34 28.30 359.3 -1.3 &AAAM28C<CR>
A minimum time interval should elapse between two commands, depending on the Baud Rate
setting:
Baud Rate
Minimum interval between two commands
9600
200 ms
19200
100 ms
38400
70 ms
57600
40 ms
115200
25 ms
(*) Break
Signal
means
interruption of
the
serial communication
for a given time interval. It is used to
inform the devices connected to the network that a command is going to be sent.
Содержание DeltaOHM HD51.3D Series
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