Frick QUANTUM LX Control Panel, Service Manual

Page: 40 / 132

QUANTUM ™ LX EVAPORATOR CONTROL PANEL
COMMUNICATIONS SETUP
090.610-CS (MAY 2016)
Page 40
In order to ensure that the Quantum™ in ques-
tion receives the data request accurately, we
must append an Error Check byte to the end of
the message. This is accomplished by adding
each of the byte pairs (hex) that we have gener-
ated thus far:
01 + 03 + 07 + D3 + 00 + 01 = DF hex
Next, subtract DF (hex) from 100 (hex):
100 (hex) - DF (hex) = 21 (hex)
: 01 03 07 D3 00 01 21 CRLF
Where:
Message Start:
Quantum™ ID #:
Read Function:
H. O. address (hex):
L. O. address (hex):
H. O. # of Data Registers:
L. O. # of Data Registers:
Error Correction Code:
Carriage Return - Line Feed:
}
After the entire data packet has been created,
simply press the [Enter] key, a Line Feed will au-
tomatically be sent also.
: 01 03 07 D3 00 01 21 CRLF
Where:
Message Start:
Quantum™ ID #:
Read Function:
H. O. address (hex):
L. O. address (hex):
H. O. # of Data Registers:
L. O. # of Data Registers:
Error Correction Code:
Carriage Return - Line Feed:
}
ASCII Write Example
To demonstrate how an address within the
Quantum™ LX may be written to, the following
test can be performed using Windows HyperTer-
minal (
NOTE : Hyperterminal cannot be used to
test RTU or TCP/IP communications).
As an example, a MODBUS® command will be
created and sent to the Quantum™ to set Regu-
lation Mode 1 Setpoint to 100.0 PSIA. First, be
aware that data sent to and received by the
Quantum™ has one decimal place assumed. This
means that to send the value of 100.0, you actu-
ally need to send 1000. Using the address tables
found later in this manual, locate the address for
the Regulation Mode 1 Setpoint. In this case, it
would be Frick® Address 7150 (decimal).
In this particular example, we are strictly looking
to request to view a data value, so we will be
performing a read function (03):
: 01 03 07 D3 00 01 21 CRLF
Where:
Message Start:
Quantum™ ID #:
Read Function:
H. O. address (hex):
L. O. address (hex):
H. O. # of Data Registers:
L. O. # of Data Registers:
Error Correction Code:
Carriage Return - Line Feed:
}
2003 decimal equals 07D3 hex. Looking at our
example, we see that we need a H.O. (High Or-
der) address and a L.O. (Low Order) address.
Since all data sent and received is in ASCII Hex
Byte format, we need to look at D3 Hex as the
Low Order portion of the address. The High Or-
der portion is 07. Now our decimal 2003 is for-
matted as 07D3 Hex.
: 01 03 07 D3 00 01 21 CRLF
Where:
Message Start:
Quantum™ ID #:
Read Function:
H. O. address (hex):
L. O. address (hex):
H. O. # of Data Registers:
L. O. # of Data Registers:
Error Correction Code:
Carriage Return - Line Feed:
}
Since we are only looking for this one address,
and no other, we can say that we are only look-
ing for one Data Address. Our Data Address part
of the data packet is also looking for a High and a
Low Order value. Fortunately, the number one (1)
is the same in decimal as it is in Hex, therefore,
the Low Order Address is 01 (hex). The High Or-
der Address is 00 (hex), so our decimal 1 is for-
matted as 0001 (hex).
: 01 03 07 D3 00 01 21 CRLF
Where:
Message Start:
Quantum™ ID #:
Read Function:
H. O. address (hex):
L. O. address (hex):
H. O. # of Data Registers:
L. O. # of Data Registers:
Error Correction Code:
Carriage Return - Line Feed:
}