Nordson Ultimus V, Operating Manual, Page: 46 / 86

2.4 Communication Sequence
The dispenser uses two communication sequences: Write (2.4.1) and Read (2.4.2).
2.4.1 Write Text Packets
Write text packets are used when the client (PLC / PC) sets a parameter on the dispenser, but does not require
feedback data.
NOTE:
Refer to “Diagram of Write Text Packet Communication between the Client and Dispenser” on page 47 for
a visual representation of the Write sequence.
The Write text packet sequence is as follows:
1. The client transmits an Enquiry ( ENQ / 0x05 ) to the dispenser.
2. When the dispenser receives the Enquiry ( ENQ / 0x05 ), the dispenser transmits an acknowledgment
( ACK / 0x06 ) back to the client.
3. When the client receives the acknowledgment ( ACK / 0x06 ), the client must send the Write text packet within
2 seconds to avoid a communication timeout.
EXAMPLE: (STX) + 08 + PS-- + 0500 + F0 + (ETX)
[In this example, the hyphens ( -- ) represent ASCII space values (hexadecimal 0x20 ].
In the above text packet, the Checksum is F0 . The Checksum calculation method is explained in 2.3.5.
NOTE: The plus signs (+) are present only to show how each character is appended to form the example text
packet; they are not part of the transmitted data. The parentheses are present only to indicate a single-byte
control character, and are also not part of the transmitted data.
The above text packet in hexadecimal format is shown below:
STX 0 8 P S space space 0 5 0 0 F 0 ETX
0x02 0x30 0x38 0x50 0x53 0x20 0x20 0x30 0x35 0x30 0x30 0x46 0x30 0x03
4. When the dispenser receives the text packet and successfully executes it, the dispenser transmits a Success
Command ( A0 ) text packet to the client.
EXAMPLE: (STX) + 02 + A0 + 2D + (ETX)
In the above text packet, the Checksum is 2D . The Checksum calculation method is explained in 2.3.5.
NOTE: The plus signs (+) are present only to show how each character is appended to form the example text
packet; they are not part of the transmitted data. The parentheses are present only to indicate a single-byte
control character, and are also not part of the transmitted data.
The above text packet in hexadecimal format is shown below:
STX 0 2 A 0 2 D ETX
0x02 0x30 0x32 0x41 0x30 0x32 0x44 0x03
Appendix B — RS‑232 Protocol (continued)
Ultimus V High Precision Fluid Dispenser
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