Cooper Instruments & Systems DFI INFINITY Digital Force Indicator/Controller - Manual (Page 19)

8. COMMAND AND RESPONSE STRUCTURE
8.1 Message String
8.1.1 “Data” and “Non Data”
Each of the many types of messages between computer or printer and the meter is transmitted or received as a
string of ASCII characters. There characters are classified as “DATA” and NON DATA”.
“DATA” is the string of measurement or non-measurement values (see Section 8.2 and 8.3) and can be
classified as:
: hexadecimal based values. Each nibble is converted to the ASCII character and transmitted or
received.
: is alphanumeric plain ASCII characters and need not be converted. It is used in Remote Display Mode.
is data which is transmitted against “X”, “V01” or external print commands. These are in decimal base,
and each digit is converted to the ASCII character and transmitted along with decimal point and sign.
“NON DATA” items are: recognition character (*), device address (nn), command prefix letter (c), command
suffix (cc), space (S or SP), carriage return (CR), line feed (LF), checksum (hh), and units of measure (uuu).
Checksum, device address, and command suffix (cc) items are hexadecimal base, and each nibble will be
converted to the ASCII character and transmitted. The rest of the “NON DATA” items are plain ASCII characters
and need not be converted (see examples in Section 8.8).
8.1.2 Brackets and Spaces
In the following text the position reserved for each ASCII character is represented by a lower-case letter.
If there must always be an ASCII character put into the message at that position, no brackets are used.
Angle brackets, “<” and “>”, are used to enclose names (or acronyms). In the actual message these names will
be replaced by the ASCII value of that name (the number of those ASCII characters is not usually the same as
the number of letters of the name inside the angle brackets).
The occurrence of non-printing ASCII characters is also indicated by angle brackets (e.g., “”).
Square brackets, “[“ and “]”, enclose items which are optional, i.e. the message is still valid when those are
omitted.
8.2 Commands and Structure
The meter responds to over 150 different commands from the computer. This section gives the format and lists
all commands by COMMAND CLASS and COMMAND SUFFIX.
8.2.1 Read Communications Configuration Command
To have the meter report its current communication parameters, the special command “^AE” is provided when
transmitted to the meter with the correct baud rate, parity information, stop bit(s), and address (if multipoint). The
meter will return 4 bytes (9 characters including carriage return) of information as follows:
Byte #1 = Recognition character
Byte #2 = Meter address
Byte #3 = Bus Format
Byte #4 = Communications Configuration
NOTE: This “Read Only” command is the only one without a leading recognition character.
Command format:
CF 125 INFINITY SC GUIDE 15 M1519/N/0605
^AE for point-to-point,
or
^AE[nn] for multipoint