2.4.1 Write Text Packets (continued)
If there is an error in the text packet, if it cannot be executed, or if the transmission was interrupted and timed
out (if the client takes more than 2 seconds to send a text packet), the dispenser transmits a Failure Command
(
A2
) text packet. Refer to “2.5 Communication Timeout” on page 50 for details.
EXAMPLE:
(STX) + 02 + A2 + 2B + (ETX)
The above text packet in hexadecimal format is shown below:
STX
0
2
A
2
2
B
ETX
0x02
0x30
0x32
0x41
0x32
0x32
0x42
0x03
If the client receives an Failure Command (
A2
) text packet, the client can either transmit another text packet or
the client can transmit an End of Text (
EOT
/
0x04
) command to end the sequence.
Diagram of Write Text Packet Communication between the Client and Dispenser
Communication Flow
Client
(PC / PLC)
Ultimus V
dispenser
ENQ (0x05)
ACK (0x06)
EOT (0x04)
STX
(0x02)
0
2
A
0
2
D
ETX
(0x03)
STX
(0x02)
0
8
P
S
Space
(0x20)
Space
(0x20)
0
5
0
0
F
0
ETX
(0x03)
NOTES:
• The
STX
(
0x02
) and
ETX
(
0x03
) control characters are
not
added when sending
ENQ
(
0x05
),
ACK
(
0x06
),
NAK
(
0x15
), or
EOT
(
0x04
). These are stand-alone / single-byte control characters.
•
Communication Timeout:
The client sends an Enquiry (
ENQ
/
0x05
) to the dispenser and receives an
acknowledgment (
ACK
/
0x06
) in response. The next text packet (such as the
PS--0500
text packet shown
previously) must be sent by the client within 2 seconds, otherwise the dispenser enters a Communication Timeout
state and responds with an Failure Command (
A2
) text packet.
Appendix B — RS‑232 Protocol (continued)
Ultimus V High Precision Fluid Dispenser
47
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