Incon 1250-LTC - 3.3 Serial RS-232 Communication

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3.3 Serial RS-232 “-S”
The Serial RS-232 option on the Model 1250-LTC can be used to program the
instrument or to retrieve position data from the instrument. It is a full-duplex, DCE
configuration.
The communication port settings: baud rate, word length, parity, stop bits, and address
are programmable using the OP 80, POrt, PORT command. (See Table 2.1 and 2.2 for
command protocol and choices.)
NOTE: When the port is programmed for 2 Stop Bits, the Parity must be “NONE”.
There are seven operating modes for the serial RS-232 port:
Serial Disabled
This mode stops all serial communication. To select this mode use
the OP 51, RS232, SERIAL command to choose mode “0”. If you are programming the
instrument through the serial port, using the serial command mode, this “disabled” mode will
not take effect until the command “EXIT” is entered. The only way to de-select this
“disabled” mode is to use the menu command OP 51, RS232, and select another mode.
Data Logger Mode
This mode causes the 1250-LTC to transmit the present position
value on the display (including sign) once a second. To select this mode use the OP 51,
RS232, SERIAL command to choose mode “1”. If you are programming the instrument
through the serial port, using the serial command mode, this mode will not take effect until
the command “RESTART” is entered.
Polled Mode When this mode is selected, the 1250-LTC can be interrogated at any
time via the RS-232 port for the current position. This is done by first instructing the
1250-LTC to latch the current position by transmitting an asterisk (*) to the unit. The position
is then extracted, one character at a time, by transmitting the digits 0 through 6. Zero causes
the sign character to be transmitted, 1 through 6 causes each position digit to be sent. The
decimal point, wherever it may be positioned, is considered to be a digit. To select this mode
use the menu command OP 51, RS232, SERIAL command to choose mode “2”.
Sampled Mode
When this mode is selected, the 1250-LTC can be interrogated at any
time via the RS-232 port for current position by transmitting a question mark (?) to the
1250-LTC. When the 1250-LTC receives a question mark, it responds by latching the current
position and transmitting the value on the display in ASCII form. To select this mode use the
menu command OP 51, RS232, SERIAL command to chose mode “3”.
Serial Command Mode This mode enables programming the instrument through the
serial port. To select this mode use the menu command OP 51, RS232 to choose mode “4”.
When this mode is selected, no other serial communication can occur. In addition, if another
Serial mode is chosen it will not be activated until the “EXIT” command is given through the
serial port command line.