Teledyne D series Installation And Operation Manual page 169

Examples
Hexadecimal Format
Using MODULO
• Acknowledgment is one character to indicate the
success of the previous transmission. There are three
possibilities: (1) E means error, resend the message
immediately (E is sent by the network controller only.
Other units signify errors by not replying; causing the
controller to resend the message). (2) B means busy,
resend message at next poll. (3) R signifies previous
message was received.
• Message source is the unit ID of the unit that origi-
nated the message. If there is no message, this location
is a space (20H).
• Length is the length of the message in 2 digit,
hexadecimal format. Maximum length is 256, with 256
being represented by a 00. This field is eliminated if
there are no messages.
• Message field is the area where the actual information
is located. The maximum length is 256 characters long.
• Checksum is also a 2 digit hexadecimal number. This
number, when added to all the previous characters in
the message (excluding control characters), will result in
a sum. If there are no errors, the result of modulo 256
division of this sum should be 0.
Frame is R304STOPD1[CR] =
(R) (3) (0)
52H + 33H + 30H + 34H + 53H + 54H + 4FH + 50H + D1H = 300H
It is important to note that all characters are converted to
the ASCII equivalent and added, except for the checksum.
The two characters of the checksum are converted to
hexadecimal numbers and concatenated to form a single
two-digit number. This number is then converted to its
ASCII equivalent and added to the end of the message.
Step 1:
22FH = 52H + 33H + 30H + 34H + 53H + 54H +4FH + 50H

Step 2:
2FH = 22FH · · 100H

Step 3: D1H = 100H 2FH
Step 4: Convert D1H to ASCII (Hex) and put at end of message.
Step 5: Put a "CR" (0DH) at the end of message for end of frame.
D Series Syringe Pumps
Section 8 Serial Interface
(4) (S) (T) (O) (P)
300H MODULO 256 = 00
100H 22FH

Modulo
200H
2R2FH
2FH
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