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Message Communications Section 6-1
6-1-3 Explicit Message Communications
Explicit messages defined by the CompoNet Network are used to send
requests for services to CompoNet Slave Units.
Explicit messages are sent using FINS commands (command code 2802).
6-1-4 Message Communications Specifications
6-1-5 Message Monitoring Timer
The message monitoring timer measures the monitoring time for responses
made by the CompoNet Master Unit. It is enabled for explicit message com-
munications. The default setting is for 2 s (2,000 ms). Any time from 1 to
65,535 ms can be set.
A longer time must be set if responses from the communications target device
(the message transmission destination) are slow. If the set time is too long,
however, subsequent messages cannot be sent to the same communications
device while waiting for a response to a previous message.
The CompoNet Master Unit monitors message timeouts using this timer. Like-
wise, monitoring is performed by the CPU Unit according to the response
monitoring time for the DELIVER COMMAND (CMND(490)) instructions. It is
therefore not effective to lengthen (or shorten) only the message monitoring
timer or only the response monitoring time for CMND(490).
Set the response monitoring time for CMND(490) to a value equal to or
greater than the time set for the response monitoring timer.
If too many timeouts are occurring, then lengthen the times for both while
maintaining the time settings relative to each other.
Applicable PLC series CS/CJ Series
Unit models CS1W-CRM21 and CJ1W-CRM21
Maximum number of
nodes per Master
Unit for message
communications
Explicit messages 448
Instructions for exe-
cuting message
communications
Any FINS commands CMND(490) instruction (FINS message sent to CompoNet Master Unit)
CompoNet explicit
messages
CMND(490) instruction (FINS message sent to CompoNet Slave Unit)
Command transmission sources: Transmis-
sion destinations
1:1 communications (1:N broadcast communications are not possible.)
Communications data length (not including
command code)
CMND(490) instruction: 542 bytes max.
Number of instructions executed simulta-
neously
One for each of eight ports (ports 0 to 7)
Note For information on ports (logical ports), refer to the section on
instructions for network communications in the CS/CJ-series PLC
Instruction Reference Manual (Cat. No. W340)
Response monitoring time Default setting: 2 s; user setting: 0.1 to 6,553.5 s
Number of retries 0 to 15
Message monitoring timer (explicit mes-
sage communications)
The setting is saved in the CompoNet Master Unit.
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