51
Communications Functions
Section 1-6
The operation of the transmission delay for data sent from the PC is illustrated
below.
1-6-2
Host Link Communications Settings and Procedures
This section explains the PC Setup settings and procedure required for Host
Link communications.
PC Setup Settings
Be sure to write 00 in the leftmost digits of DM 6645 (RS-232C port) or
DM 6650 (peripheral port) to specify Host Link communications. Other Host
Link communications parameters are set in the rightmost two digits of
DM 6645/DM 6650 and DM 6646/DM 6651.
A node number must be set for Host Link communications to differentiate
between nodes when multiple nodes are participating in communications.
This setting is required only for Host Link communications.
The node number is normally set to 00. Other settings are not required unless
multiple nodes are connected in a network.
Overview of Host Link
Communications
Host Link communications were developed by OMRON for the purpose of
connecting PCs and one or more host computers by RS-232C cable, and con-
trolling PC communications from the host computer. Normally the host com-
puter issues a command to a PC, and the PC automatically sends back a
response. Thus the communications are carried out without the PCs being
actively involved. The PCs also have the ability to initiate data transmissions
when direct involvement is necessary.
In general, there are two means for implementing Host Link communications.
One is based on C-mode commands, and the other on FINS (CV-mode) com-
mands. The CQM1H supports C-mode commands only. For details on Host
Link communications, refer to
SECTION 6 Host Link Commands.
Response/data
sent
Transmission delay
Response/data
sent
Transmission delay
Response/data
sent
Transmission delay
Response/data
sent
Time
1st send
from PC
2nd send
from PC
3rd send
from PC
4th send
from PC
15
0
Bit
0 0
Node number
(2 digits BCD): 00 to 31
Default:
00
DM 6648: RS-232C port
DM 6653: Peripheral port
