Anybus Communicator Modbus plus, Руководство пользователя

Страница: 36 / 83

Transactions 34
Doc.Id. SCM-1200-093
Anybus Communicator for Modbus Plus
Doc.Rev. 3.01
6.3 Transaction Parameters (Master Mode)
6.3.1 Parameters (Query & Broadcast)
(To gain access to these parameters, select a Query- or Broadcast- transaction in the Navigation Section)
Parameter Description
Minimum time between
broadcasts (10 ms) This parameter specifies how long the gateway shall wait after transmitting a broadcast trans-
action before processing the next entry in the scanlist. The value should be set high enough to
allow the slave devices time to finish the handling of the broadcast.
The entered value is multiplied by 10. For instance, an entered value of 5 results in 50 ms.
Note: This setting is only relevant for the Broadcaster node.
Offline options for field-
bus This parameter specifies the action to take for this transaction if the higher level network goes
offline. This affects the data that is sent to the subnetwork.
• Clear - The data destined for the slave-devices is cleared (set to zero)
• Freeze - The data destined for the slave-device is frozen
• NoScanning -The updating of the subnetwork is stopped
Offline options for sub-
network This parameter specifies the action to take for this transaction if the subnetwork goes offline.
This affects the data that is reported to the control system.
• Clear - Data is cleared (0) on the higher level network if the subnetwork goes offline
• Freeze - Data is frozen on the higher level network if the subnetwork goes offline
Reconnect time (10 ms) This parameter specifies how long the gateway shall wait before attempting to reconnect a dis-
connected node. A node will be disconnected in case the maximum number of retries (below)
has been reached.
The entered value is multiplied by 10. For instance, an entered value of 5 results in 50 ms.
Note: This setting is not relevant for the Broadcaster node.
Retries
This parameter specifies how many times a timeout may occur in sequence before the node is
disconnected.
Timeout time (10 ms)
This parameter specifies how long the gateway will wait for a response from a node. If this time
is exceeded, the gateway will retransmit the Query until the maximum number of retries (see
above) has been reached.
The entered value is multiplied by 10. For instance, an entered value of 5 results in 50 ms.
Trigger byte address This parameter specifies the location of the trigger byte in internal memory (only relevant when
‘Update mode’ is set to ‘Change of state on trigger’).
Valid settings range from 0x200... 0x3FF and 0x400... 0xNNN
Update mode This parameter is used to specify when the transaction shall be sent to the slave:
• Cyclically
The transaction is issued cyclically at the interval specified in the ‘Update time’ parameter.
• On data change
The data area is polled for changes at the time interval defined by Update time. A transac-
tion is issued when a change in data is detected.
• Single shot
The Query is issued once at start up.
• Change of state on trigger
The Query is issued when the trigger byte value has changed. This feature enables the
control system to notify the gateway when to issue a particular Query. To use this feature
correctly, the control system must first update the data area associated with the Query/
transaction, then increase the trigger byte by one. The location of the trigger byte is spec-
ified by the ‘Trigger byte address’ parameter.