- 9 -
5. RS232 & RS485 COMMUNICATION PROTOCOLS
5.1 SERIAL COMMUNICATION FORMAT
The serial communication format for both RS232 and RS485 is the following:
Mode ................ Full Duplex (Separate transmit and receive lines) and Half Duplex (RS485 only)
Baud Rate ......... 300, 600, 1200, 2400, 4800, 9600, 19200 selectable by front panel Menu item
“Ser 1”, Sub-menu item “Digit 4” for DPM, "Digit 5" for counter.
Parity ................ None
Word length ...... 8 data bits
Stop bit ............ 1
5.2 MEASUREMENT DATA FORMAT
The basic measurement data format consists of 8 ASCII characters for the DPM, such as
+999.99<CR> and 9 characters for the counter, such as +9999.99<CR>, where <CR> is the
carriage return character. The first character is always a plus or minus sign. A decimal point is
always furnished, even when it follows the last digit.
Adding a Line Feed Character to the Basic Format
Printers and other devices that receive the measurement data may require a line feed character
<LF> following the <CR>. The line feed character <LF> may be selected in “Ser 2”.
Adding a Coded Data Character to the Basic Format
It is possible to add a coded character from A to H to the data string according to the following
table to indicate the alarm and overload status of the device. If used, this character precedes
the <CR>, so it is the last printable character in the string. With the optional <LF> and coded
character selected, the data string will consist of 10 characters for the DPM +999.99A
<CR><LF> and 11 characters for the c9999.99A<CR><LF>.
Alarm Status
No Overload
Overload
Neither Alarm set
Alarm 1 set only
Alarm 2 set only
Both Alarms set
A
B
C
D
E
F
G
H
For example, a coded character “G” indicates that Alarm 2 only is set, that the DPM is in the
overload condition, and that zero blanking has been selected. This information is useful when
data is supplied to a computer for listing and analysis, or when data is supplied to a Remote
Display in a Master-Slave configuration.