6. Configuring the Gateway

6.11.2.2. Configuring the Query

Select the “Query” element from the Modbus command. The various elements of the configuration of the query for this command are shown opposite. The values displayed correspond to the default values for any new command.

These elements allow you to configure how the whole command is managed, including how degraded modes are managed (number of re-transmissions, for example).

Each of these elements is described, in order, in the table below. When a unit is assigned to an element, it is shown in brackets after the name of the element.

Configuration

Description

element

 

Minimum time

This element is only relevant if you have added a “Broadcaster” node (see chapter 6.13

between

Adding a Broadcaster Node, page 85). This parameter then allows you to specify a waiting

broadcasts

time following the transmission of the selected broadcast command. The next Modbus

(10ms)

message, whatever it is, will only be transmitted by the gateway once this time has elapsed.

 

So it needs to be long enough to allow the slowest Modbus slave to process the command

 

which has been broadcast. This parameter is not used by commands which do not belong

 

to a broadcaster node.

 

With the LUFP7 gateway’s default configuration, this feature has not been used, so as to

 

control the Modbus slaves individually.

Offline options

This element affects the data sent to the Modbus slave, but only in the query to which this

for fieldbus

element belongs to, whenever the gateway is disconnected from the Profibus-DP network.

 

This element takes one of the following three values:

 

- Clear ..............From now on all data sent to the Modbus slave using this query is set to

 

16#0000 (resetting of the output data in the gateway’s memory).

 

- Freeze ...........All data sent to the Modbus slave using this query retains its current values

 

(the output data in the gateway’s memory is frozen).

 

- NoScanning ...The query is no more transmitted to the Modbus slave by the gateway

Offline options

This element affects the data sent to the Profibus-DP master PLC whenever the query to

for sub-network

which this element belongs to has not been answered with a response by the Modbus slave

 

(no response). This element takes one of the following two values:

 

- Clear ..............From now on the data sent to the Profibus-DP master PLC is set to

 

16#0000 (resetting of the input data in the gateway’s memory).

 

- Freeze ...........From now on the data sent to the Profibus-DP master PLC retains its current

 

values (the input data in the gateway’s memory is frozen).

 

N.B. exception responses issued by the Modbus slaves do not trigger the use of these “Offline options!”

Reconnect time

If there is no response from the Modbus slave to a query, or following the receipt of an

(10ms)

incorrect response, the gateway uses the “Retries” and “Timeout time (10ms)” elements to

 

carry out re-transmissions. If the Modbus slave has still not responded correctly following

 

these re-transmissions, the gateway stop sending it the corresponding query for a period of

 

time which can be adjusted using “Reconnect time (10ms)”.

 

When this period is over, the gateway attempts to restore communication with the Modbus

 

slave.

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Schneider Electric LUFP7 user manual Configuring the Query, Configuration Description Element