Datasheet

Modbus TCP Communication HIMA H41q/H51q ↔
↔↔
↔ Emerson DeltaV
8
Figure 2.7: DeltaV Serial Port Properties
The “Retry Count” is recommended to be set to 3 so that delays in request processing on the slave
side do not provoke communication disruptions. The “Message Timeout” could be set to slower values
like the used 2000 ms but should be set to times well above the PESs cycle time. The configuration of
the third tab “Communication” is not necessary for Modbus TCP communication as this tab applies
only to serial communication.
The data for serial communication in DeltaV is organized in so called Datasets. One Dataset can
contain up to 100 values (50 values for real data). One serial card port can handle up to 16 datasets in
up to 16 devices (meaning 16 devices with each one dataset up to one device with 16 datasets). Each
serial card offers two ports. One pair of VIMs supports in sum four redundant or eight simplex
simulated serial cards therefore amounting to 12,800 respectively 25,600 data values which could be
theoretically be imported to or exported out of DeltaV.
Figure 2.8: Dataset Properties