Instruction manual

IMR01H02-E3
15
5. RKC COMMUNICATION PROTOCOL
The MA900/MA901 (hereafter, called controller) uses the polling/selecting method to establish a data
link. The basic procedure is followed ANSI X3.28 subcategory 2.5, A4 basic mode data transmission
control procedure (Fast selecting is the selecting method used in this controller).
!"The polling/selecting procedures are a centralized control method where the host computer
controls the entire process. The host computer initiates all communication so the controller
responds according to queries and commands from the host.
!"The code use in communication is 7-bit ASCII code including transmission control characters.
The transmission control characters are EOT (04H), ENQ (05H), ACK (06H), NAK (15H),
STX (02H) and ETX (03H). The figures in the parenthesis indicate the corresponding
hexadecimal number.
In RKC communication, both multi-point and single modes are available. If the single mode
is required, contact our sales office or agent.
5.1 Polling
Polling is the action where the host computer requests one of the connected controllers to transmit
data. An example of the polling procedure is shown below:
Host
computer
send
Host
computer
send
Host com
p
uter send
Controller
send
Controller send
E
O
T
E
O
T
E
N
Q
E
O
T
E
T
X
S
T
X
E
O
T
A
C
K
N
A
K
[
Data
]
[
BCC
]
[
ID
]
(1)
(2)
(5)
(3)
(4)
(9)
(7)
(10)
[Address] [ ] [ ID ]
No res
p
onse
No
response
Indefinite
Time
out
ID: Identifier
(8)
(6)
Memory area
number