Schneider Electric LUFP7 user manual Default communication mode. The query is transmitted

6. Configuring the Gateway

Configuration	Description
element
Update mode	This element is used to specify the transmission mode for the query on the Modbus
	network. It takes one of the following four values:
	- Cyclically	Default communication mode. The query is transmitted
	periodically on the Modbus network (see “Update time”).
	- On data change	The gateway transmits the query on the Modbus network
	when at least one item of data from this query is changed by the Profibus-DP master.
	So this is an aperiodic communication mode. For instance, this is not the case with
	the queries associated	with “Transactions 1” and “Transactions 2” personalized
	commands for the “TeSys U n°1” node of the gateway’s default configuration. These
	queries are transmitted when at least one of the values of their output data
	(addresses 16#0212 to 16#0217 or addresses 16#0218 to 16#0220D) is changed by
	the Profibus-DP master. So all data from a single query must be updated by the
	Profibus-DP master at the same time. If you are not certain whether your software is
	able to update all the output data from a query at the same time, we recommend
	using “Change of State on trigger” mode for these two commands.
	- Single Shot	This transmission mode only allows a single Modbus
	exchange for the whole of the time that the gateway is operating. This exchange
	takes place just after the initialization of the gateway.
	- Change of state on trigger	With this aperiodic communication mode, the Modbus
	query is sent every time that the Profibus-DP master changes the value of an 8-bit
	counter designated by the “Trigger byte address” element. Please see the description
	of this element for further information about how to use this communication mode.
Update time	This element is only used by the gateway if “Update mode” is set to “Cyclically”. In this
(10ms)	case, it specifies the query’s transmission period on the Modbus network.

E.g.: With the ATS48, we will be using the configuration shown opposite. The most notable points of this configuration are:

•On disconnection the data is reset on one of the two networks.

•3 re-transmissions with a 100 ms timeout.

•Periodic communications with a cycle time set to 300 ms.

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