S90-510 CS (MAR 07)
FRICK
®
QUANTUM™ LX AcuAir
®
CONTROL PANEL
Page 36
COMMUNICATIONS SETUP
Response Example:
Using the Query (Read) Message example used earlier, if
the packet was properly received by the Quantum™, you
should see an immediate response in HyperTerminal. In
the Query Response (read function) example used earlier,
a response of :01030200DC1E (hex) was received.
Once again, the first part of the message will be a Colon
( : ). This represents a “heads up” alert that data is coming
“down the line”, but since the data is coming from the
Quantum™ to the
Leader
this time, the
Leader
will
accept it.
After having received the Colon ( : ), the
Leader
will look
at the two bytes that follows it, so that it may determine
from which Quantum™ the message is coming from.
Now that the
Leader
knows which panel is responding, it
needs to known which function the panel is responding to.
In this case, it sees that it is a read function, and the
Quantum™ is merely returning a value that was previously
requested.
The next byte tells the
Leader
how many bytes
of information are being returned as a response. In this
case, there are two (2) bytes of valid data.
The next two bytes (in this case) are the actual data in
response to our original request.
We need to know what this value means. To break it
down, we must convert the pair of bytes from Hex to
Decimal:
00DC (hex) = 220 (decimal)
Data sent to and from the Quantum™ consist of numbers
having one decimal place. Therefore:
220 (decimal) = 22.0 (decimal)
All temperatures are in degrees C and all pressures are in
PSIA unless the command is sent to select the units of the
panel. Therefore:
22.0 (decimal) = 22.0 C
Therefore, the value of the Outside Air Temperature for
Unit 1 is 22.0
°
C.
ASCII NOTES:
This has been an example of how the Quantum™
Controller uses the MODBUS
®
Protocol. It is hoped that
the information provided here will assist the end user in
writing applications that will allow the Quantum™ to be
implemented into networks that the customer may already
have in use.
This information is subject to change at any time, and is
provided as a reference only. Not all areas of the
MODBUS
®
Protocol can be handled in this document.
Some additional information regarding MODBUS
®
Protocol
that the end user should be aware of:
•
There are many versions of MODBUS
®
Protocol
that is available, and an application that works
}
: 01 03 02 00 DC 1E
Where:
Start of Message
Quantum™ ID #
Read Function
Number of Bytes Returned
Data
Error Correction Code
}
: 01 03 02 00 DC 1E
Where:
Start of Message
Quantum™ ID #
Read Function
Number of Bytes Returned
Data
Error Correction Code
: 01 03 02 00 DC 1E
{
Where:
Start of Message
Quantum™ ID #
Read Function
Number of Bytes Returned
Data
Error Correction Code
: 01 03 02 00 DC 1E
{
Where:
Start of Message
Quantum™ ID #
Read Function
Number of Bytes Returned
Data
Error Correction Code
: 01 03 02 00 DC 1E
Where:
Start of Message
Quantum™ ID #
Read Function
Number of Bytes Returned
Data
Error Correction Code