Request Messages; Figure 3-2 Request Message Fields - Honeywell UDC2300 Product Manual

3.4

Request Messages

What is a request
message?
Request message
fields
Figure 3-2 Request Message Fields
,
Station
Address
A two digit device
address – 01 to 99
Comma
Delimiter
required to separate fields
Protocol Field
4204 – selects checksum
protocol
0204 – ignores checksum
UDC Status (hexadecimal)—see matrix below
UDC State and Mode
0 = Slave, Manual
2 = Slave, Toggle between LSP/RSP*
4 = Slave, Automatic
6 = Slave, No Change
E = Monitor, No Change
Change from RSP to LSP or LSP to RSP
*
READ only in Monitor Mode
**
READ and WRITE in Control Mode
Used after WRITE to verify data
***
transaction
20 RS422/485 ASCII Communications Option Product Manual
Your computer queries a controller and indicates the communication
function, or operation, that the controller should perform by sending a
request message. Request messages are composed of standard fields,
separated by commas. Each field contains a certain kind of information,
which you must enter in order to have a valid request message.
Figure 3-2 shows the request message fields and the selections that may be
entered into each field. Table 3-4 lists these selections and their
definitions.
– REQUEST –
, ,
= Single Byte Decimal – unsigned (digital configuration list) – for
11
Parameter codes 128 to 255
= Single Byte Decimal – unsigned (extended digital configuration
41
list) – for Parameter codes 128 to 158 in extended configuration
= Oxford Floating Point (analog configuration list) – for Parameter
18
codes 001 to 125
= Oxford Floating Point (extended analog configuration list) – for
48
Parameter codes 001 to 021 in extended configuration
= ASCII Text (Loopback only)
DD
= ASCII Text (Analog configuration list for parameter
I D
I D Code #103 - Totalizer value (UDC6300, UDC3300 only)
Protocol Class and Operation Code
4 = Configuration, Read**
5 = Configuration, Write**
6 = Configuration, Ready*** (only E6)
8 = Loopback (only E8)
Protocol
Mode
SLAVE
MAN
SLAVE
TOGGLE
SLAVE
AUTO
SLAVE
NO CHNG
MON
NO CHNG
, ,
Data Field
READ – Item no. only
WRITE – Item no., value
READY – 000
LOOPBACK – ASCII text
Data Type Field
CONF CONF CONF
READ WRITE READY
00000100 00000101 00000110
04 05 06
00100100 00100101 00100110
24 25 26
01000100 01000101 01000110
44 45 46
01100100 01100101 01100110
64 65 66
11100100 11100110
E4 X E6 E8
CR LF
Checksum Field
HH=2-digit Hex
representing
calculated checksum
LOOP
BACK
X
X
X
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