8-4
Section
Message Service Delay Times
123
8-4
Message Service Delay Times
The following diagram illustrates the maximum message service transmis-
sion delay time. In this example, the MEMORY AREA READ FINS command
is sent to the PC at node #2 (a CS1-series PC) by the user application at the
computer at node #1.
User application
Maximum transmission delay
(ClkSendFins)
(ClkRecvFins)
Computer at
node #1
Receive processing at
node #1 (response)
Transmission delay
(response)
Communications cycle
Send processing at node
#2 (response)
PC at node #2
Transmission delay
(command)
Receive processing at
node #2 (command)
Send processing at node
#1 (command)
Maximum transmission delay time = Send processing (node #1) + Communica-
tions cycle time + Transmission delay time (for command) + Receive processing
(node #2) + PC processing time (node #2) + Send processing (node #2) + Com-
munications cycle time + Transmission delay time (for response) + Receive pro-
cessing (node #1)
Send/Receive Processing at Node #1
Depends on the processing capacity of the computer that is used.
Communications Cycle Time
See 8-2 Communications Cycle Time (on page 116).
Transmission Delay Time
Transmission delay time varies with the baud rate.
Baud rate
Transmission delay time
2 Mbps
Number of words transferred
×
0.008 + 0.112 ms
1 Mbps
Number of words transferred
×
0.016 + 0.224 ms
500 Kbps
Number of words transferred
×
0.032 + 0.448 ms
Receive Processing at Node #2
Number of words transferred
×
0.00125 + 2.3 ms
Send Processing at Node #2
Number of words transferred
×
0.00125 + 3.0 ms
Note
1. The I/O response time can increase due to noise or restrictions on the num-
ber of frames that can be transmitted while data links are operating.
2. Refer to the Controller Link Units Operation Manual (W309) for details on
the time from reception at the Controller Link Unit until transmission.
