Rockwell Automation Allen-Bradley AADvance T9110, Руководство по решениям

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54 Rockwell Automation Publication ICSTT-RM447M-EN-P - July 2019
Chapter 3 Controller Functionality
SNTP The AADvance controller supports the Simple Network Time Protocol
(SNTP) service that can circulate an accurate time around the network. As an
SNTP client the controller will accept the current time from external Network
Time Protocol (NTP) and SNTP network time servers.
SNTP clients settings tell the controller the IP address of the external server;
the version of SNTP offered by the server; and the operating mode for the time
synchronization signal that the processors will use for their real time clock.
An AADvance controller can also fulfill the role of one or more SNTP servers
(one for each processor) to supply a network time signal throughout the
network. To enable server time on an interface it is necessary to give the direct
broadcast address for that interface. This works for broadcast or unicast modes.
This way of configuring is derived from the NTP configuration command
language.
CIP and its Producer and
Consumer Variables You can configure CIP produce and consume variables for an AADvance
controller.
One or more controller Ethernet ports may be used for CIP communications
so long as they are on separate subnets.
Consideration must be given to the number and mix of produce/consume
variables being used.
Each CIP consumer variable identifies the ControlLogix® controller and the
tag produced by that controller, which provides a value to be consumed.
The AADvance controller sets its consumer variables to the most recent
received value at the start of its application scan, before executing the logic.
The controller updates its producer variables at the end of its application scan,
after executing the logic. The AADvance controller uses the most recent value
of a producer variable when sending a packet.
You cannot define a default value for a consumer variable. If the connection
fails (typically because the communications link fails), the most recently
received value of the consumer variable is retained. The maximum size of a CIP
variable is 500 bytes.
If the variable is a structure having a mixture of element types, then each
element starts on a new byte or word depending on its size. For example, a
DINT following a single bit BOOL will start on a new 4 byte boundary.
Also:
• A LINT Must ALWAYS align on a 64 bit (8byte) boundary.
• Any UDT that contains a LINT must ALWAYS be of a size that is
divisible by 8 bytes