Teledyne SyriXus 65x Installation And Operation Manual page 158

SyriXus Series Pumps Installation and Operation Guide
Section 8 Serial Interface
Examples
Hexadecimal Format
Using MODULO
EAR99 Technology Subject to Restrictions Contained on the Cover Page
8-16
• Destination - The 1-digit unit identification number of the
instrument to receive the message.
• Acknowledgment - 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 - The unit ID of the unit that originated the
message. If there is no message, this location is a space (20H).
• Length - 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 - The area where the actual information is located.
The maximum length is 256 characters long.
• Checksum - 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) (4)
52H + 33H + 30H + 34H + 53H + 54H + 4FH + 50H + D1H = 300H
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 sin-
gle 2-digit number. This number is then converted to its ASCII equiv-
alent and appended to the end of the message.
Step 1
22FH = 52H + 33H + 30H + 34H + 53H + 54H +4FH + 50H
Step 2

2FH = 22FH ·

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.
(S) (T) (O) (P)
300H MODULO 256 = 00
NOTE
· 100H
100H
Modulo
2R2FH
22FH

200H
2FH