4. COMMUNICATION PROTOCOL
IMSRM04-E8
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4.1.1 Polling procedure
(1) Data link initialize
In order to initialize the data link before sending the polling sequence, send [EOT] from the host
computer.
(2) Polling sequence send
Send the polling sequence from the host computer in the following format.
c
c
c
c
Address
This is the unit address of this device being polled.
It is expressed by a 4-digit decimal ASCII code.
When the connection is directly to the control unit and not to the operation panel, the operation
panel address number is abbreviated into 2 digits.
d
d
d
d
Identifier
A code which identifies the data requested from this device.
It is expressed using a 2-digit alphanumeric ASCII code.
For details on the identifiers, see
5. COMMUNICATION IDENTIFIERS
.
e
e
e
e
[ENQ]
This transmission control character signifies the end of the polling sequence. After sending this,
the host computer waits for a response from this device.
(3) Data send from this device
This device sends data in the following format if it received the polling sequence correctly.
If the length of send data (from [STX] to [BCC]) exceeds 128 bytes, it is divided into blocks
by [ETB]. In this case, the succeeding divided data is sent after [STX].
Address
ENQ
Identifier
e
d
c
0
0
0
0
or
Identifier
Data
BCC
ETB
STX
d
h
f
e
c
Identifier
Data
BCC
ETX
STX
d
h
g
e
c
Control unit address number (2 digits)
Operation panel address number (2 digits)
