FRICK
®
QUANTUM™ COMPRESSOR CONTROL PANEL S90-010 CS (APR 08)
COMMUNICATIONS SETUP Page 15
Quantum™
$
Protocol Specifications
Quantum™ (
$
) protocol commands have been added
specifically for the Quantum™. Unless otherwise shown, 9
characters are returned from the Quantum™ for a data
value. The data value includes two decimal fields and the
first character position is either;
-
if the value is negative,
or it is
+
if the value is positive. For example, if the data’s
value is 25.5; then the value +00002550 is sent. All
temperatures are in degree C and all pressures are in
PSIA. A mode such as Slide Valve mode is returned as an
integer value that represents the mode that it is in. For
example, a +00000000 is sent if it is in manual, or a
+00000100 is sent if it is in automatic, or a +00000200 is
sent if it is in remote. The value zero +00000000 is used to
represent an
OFF
status and a
DISABLED
option. The
value one +00000100, which is received as a 1, is used to
represent an
ON
status and an
ENABLED
option.
Setpoints are only changed if the value sent is within the
acceptable range. Reference the
Frick
®
Quantum™
Control Panel Maintenance
publication S90-010 M for the
setpoints default settings and ranges. The checksum is
the 2 byte hexadecimal sum of each character within the
command or returned answer excluding the command
type identifier,
$
. If the command’s checksum is replaced
with
??
, the Quantum™ returns a response without using
checksum error checking on the received command (refer
to the
Data Packet
section for more information). If the
Quantum™ detects a checksum error, a
N
(Not
Acknowledged), the Compressor ID code,
02
, Carriage
return, and Linefeed are returned.
This document will demonstrate how to communicate to the
Quantum™ panel using the tables that appear on the
following pages.
Data Packet
If you were interested in viewing the information that is
displayed on the
Operating Status - Page 1
screen
(
Home
screen), you would want to refer to the table
entitled
RETURN OPERATING STATUS Page 1 data:
$01D1
table
on the next page.
The quickest and easiest way to demonstrate this protocol
is through Hyperterminal (see the section entitled
Hyperterminal
later in this manual). After setting up
Hyperterminal and ensuring that all wiring and jumper
configurations are correct, type a
$
symbol. This is the
character that will alert all of the Quantum™ panels on the
communications line that data is on its way. Following the
$
symbol, type the ID code of the Quantum™ that you wish
to query (for instance
01
for the first Quantum™). After the
ID number, type a
D1
. The protocol code in the Quantum™
recognizes this portion of the data packet as a request for
the data that is displayed on the
Operating Status - Page
1
screen.
Up to now you have typed the following information:
$01D1
. The next thing that must be done is to enter a
checksum value. You may elect to type in a
??
as a
wildcard if you do not have the time to figure the correct
checksum, however, the information that is returned may or
may not always be reliable. The checksum will ensure
reliability.
To arrive at the checksum value for the command you have
just typed, you will need to convert each ASCII digit into
hexadecimal (do not include the
$
symbol). For this
example, you will need to take the first digit
0
, and referring
to the Conversion Chart at the end of this section, look
down the ASCII column until you find
0
. You will notice that
the Hexadecimal equivalent for ASCII
0
is
30
hex. Repeat
the process of looking up each digit in the ASCII column,
and finding its equivalent in the Hexadecimal column, and
write each value down. When all four digits (01D1) have
been converted to hexadecimal, you will need to add the
four values together. Remember, the values are in
hexadecimal format, not decimal. If you are not familiar
with hexadecimal math, you may wish to utilize the
calculator that comes with Microsoft Windows. Look at the
following chart:
ASCII Value of
Data Packaet
Hexadecimal
Equivalent
0 30
1 31
D 44
1 31
Hex Total =
D6
The answer that is arrived at from the previous chart is
D6
.
This will become the checksum for the data packet, and is
appended to the end of the data that has so far been typed
in
.
NOTE:
For any calculation that results in an answer of
more than two digits, use only the right most two digits, and
disregard all digits to the left.
The result should look like this:
$01D1D6
Press the
[Enter]
key. You should see an immediate
response. The format of this response should resemble
something (but not necessarily exactly) like:
A01+0000000154
15+00000000000
0+000000231-00027249B6
Referring to the
RETURN OPERATING STATUS Page 1
data: $01D1
table on the next page, we find that the first
line of the response,
A01
, indicates that an
Acknowledgement (A) was received from device 01 (01).
This is followed by
+00006166
(Suction Pressure). The
plus (+) symbol indicates a positive value, followed by
00006166
. Since there are two decimal positions assumed,
0006166
equals 61.66 PSIA. Using the
+/-
symbols as a
delimiter in the above example, each section of 8 digits can
be interpreted by comparing it with the
Operating Status
table. The
B6
value at the very end of the response is the
checksum value that the Quantum™ returned, not actual
data.
