Nordson Ultimus V, Operating Manual, Page: 42 / 86

2.2 Data Encoding
RS-232 communication is accomplished by using text packets that include one or more elements. All text packets
passed between the Ultimus V dispenser and the client (PC / PLC) are encoded in ASCII.
The ASCII control characters shown below are used to synchronize communication between the dispenser and the
client. These ASCII control characters must be sent as a single byte (their hexadecimal value) — not as the their text
abbreviations.
CORRECT: ENQ is sent from the client as a control character using its hexadecimal (hex) value of 0x05
[Dec (Decimal) 5], not as the text characters “E,” “N,” and “Q.”
INCORRECT:
The client sends “E,” “N,” and “Q” as text characters, which means the dispenser will
not
respond.
The following ASCII control characters are used as part of the communication protocol:
Name Abbreviation Binary Dec Hex
Caret Notation
(see NOTE)
Start of Text STX 0000 0010 2 0x02 ^B
End of Text ETX 0000 0011 3 0x03 ^C
End of Transmission EOT 0000 0100 4 0x04 ^D
Enquiry ENQ 0000 0101 5 0x05 ^E
Acknowledgment ACK 0000 0110 6 0x06 ^F
Negative Acknowledgment NAK 0001 0101 21 0x15 ^U
Space
-
0010 0000 32
0x20
[space bar]
Zero 0 0011 0000 48 0x30 0
… … … … … …
Nine
9
0011 1001 57
0x39
9
A A 0100 0001 65 0x41 A
… … … … … …
Z Z 0101 1010 90 0x5A Z
NOTE:
The caret notation is sometimes used to display the control characters, which are normally not visible.
Additionally, many terminals allow typing of control characters by holding down the Ctrl key and pressing the
corresponding caret notation key.
EXAMPLE: To send the ENQ control character, press Ctrl+E.
Appendix B — RS‑232 Protocol (continued)
Ultimus V High Precision Fluid Dispenser
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