CHAPTER 4, DIGITAL COMMUNICATION
98307600 Rev. C-1 4-13
A bad block check on a Bavarian command will cause the response <NAK>BAD
BLOCK CHECK<CR><LF>.
If a Bavarian command is sent without a set of matching <STX> and <ETX>
characters it will cause the response <NAK>BAD STX ETX PAIR<CR><LF>.
4.4.3.12 Enhanced Protocol Idiosyncrasies
The string DA<CR> is a valid command.
The DA command will function without an I.D.
The data type must be sent on 9800 style commands but it is not checked
against the actual parameters.
The number of data parameters must be sent on 9800 style commands, but it is
not checked against the actual parameters.
4.4.4 Establishing Communications
The first step in establishing communications with the EC9830 is to connect a
computer or terminal to one of the instrument's RS232 serial ports as specified in
section 4.2.1. The default serial configuration for either serial port is 2400,8,N,1
(2400 baud, 8 bits, no parity, and one stop bit). If you need to change the serial
configuration from the default, use the INTERFACE MENU.
Once the instrument has been connected, place the instrument in Command mode
by entering the INTERFACE MENU via the front panel and selecting COMMAND as the
INTERFACE MODE. Then, using a communication package such as HYPER
TERMINAL establish communications with the instrument.
To test the communication connection type DCOMM,??? and press the Enter key.
The complete alphanumeric set recognized by the EC9830 should be displayed on
the computer followed by END OF MULTI-DROP PORT TEST
4.4.4.1 Multidrop Communications
The term multidrop is an idiomatic contraction of the term multiple drops. It is a
term used to denote a parallel connection of multiple RS232 transceivers. In this
scheme, all receivers share the same receive line that comes from a single master.
Likewise, these multiple transceivers share the same transmit line which goes
back to a single master. This strategy is a method of attaching multiple slave units
(instruments) to a single master (computer).
In the multidrop strategy, each unit is given an identification number (I.D.) which
is sent with each command from the master. When a unit recognizes its unique
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