Omega A2400 - Manual (Page 8)

Getting Started 1-4
This message is terminated with a carriage return. If the response message
cannot be obtained, re-check all the wiring, making sure that the proper
power is on the A2400 connector and that the DEFAULT* line is shorted to
the GND pin. The terminal must be set to 300 baud.
If, after several attempts, the response message does not appear, refer to
Chapter 8 Troubleshooting in this manual.
If you have an IBM PC or compatible computer, running the S1000 setup
software will ease the task of setting up the A2400 for your application.
After establishing communications with the A2400, read the manual and feel
free to experiment with the various commands and setups available. If
communications is lost due to an improper setup, returning back to the hook-
up of Figure 1.2 will restore communications to the A2400.
Default Mode
The A2400 contains an EEPROM (Electrically Erasable Programmable
Read Only Memory) to store setup information. The EEPROM replaces the
usual array of switches necessary to specify baud rate, address, parity, etc.
The memory is nonvolatile which means that the information is retained
even if power is removed. No batteries are used so it is never necessary to
open the module case.
The EEPROM provides tremendous system flexibility since all of the setup
parameters may be configured remotely through the communications port
without having to physically change switch settings. There is one one minor
drawback in using EEPROM instead of switches; there is no visual indication
of the setup information in the module. It is impossible to tell just by looking
at the A2400 what the baud rate, address, parity and other settings are. It
is difficult to establish communications with a A2400 whose address and
baud rate are unknown. To overcome this, the A2400 has a pin labeled
DEFAULT*. By connecting this pin to ground (GND) the A2400 is forced to
a known communications setup called Default Mode.
The Default Mode setup is: 300 baud, no parity, any address is recognized.
Grounding the DEFAULT* pin does not change any of the setups stored in
EEPROM. The setup may be read back with the Read Setup (RS) command
to determine the communications parameters stored in the A2400.
An A2400 in Default Mode will respond to any address except the six illegal