Archived: Network Parameter Settings for the Fisher-Rosemount 3244MV

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Advanced Network Parameters

Advanced Network parameters control the interaction and communications of devices over the network, and these parameters are all related to the Management Information Base (MIB). Some Fieldbus devices have different default network parameter settings, they do not appear or work well in NI-FBUS software when connected, so users need to make some changes to adjust the parameter settings to make these devices work properly.

Fieldbus Foundation Recommended Default Settings 
The Fieldbus Foundation recommended the following default values as the initial link settings where interoperability is uncertain. Tighter settings will result in better network performance, but may cause interoperability problems for some equipment.

T1 = 480000
T2 = 2880000
T3 = 1440000 (1/32 ms)
Slot Time = 8
Maximum Response Delay = 10
Minimum Inter-PDU Gap = 16
Time Sync Class = 1 ms

NI Recommended Default Settings 
National Instruments Fieldbus software also has its own default settings for a better network performance These settings would speed the interactions and communication of devices on the bus but it might cause some communication problems for some devices.

T1 = 262144
T2 = 262144
T3 = 196608 (1/32 ms)
Slot Time = 5
Maximum Response Delay = 5
Minimum Inter-PDU Gap = 10
Time Sync Class = 1 ms

Modifying the Network Parameters

Changes can be made either in the NI-FBUS Interface Configuration utility or in the NI-FBUS Configurator. They are set on a port-by-port basis.

In the NI-FBUS Interface Configuration utility: select the port to which the fieldbus device is connected. Click on the Edit button. In the next window, click on the Advanced button. Change the setting values.

In the NI-FBUS Configurator: these changes are made by right-clicking on the link (the top level in the hierarchy) and selecting Advanced View. Now the MIB parameters appear underneath the representation of the interface board. Double-clicking on the MIB will bring up a parameter window where these values can be changed. Change the setting values.

Network Parameter Settings for Some Specific Devices

Fisher-Rosemount 3244MV
The Fisher-Rosemount 3244MV revision 3 temperature transmitters are intrinsically safe link master devices. With the default network parameter settings, they do not appear when connected to the bus. The revision 2 of the 3244MV appears without adjustments.

T1 = 96000
T2 = 1920000
T3 = 150000 (1/32 ms)
Slot Time = 8 or higher
Maximum Response Delay = 3 or higher
Minimum Inter-PDU Gap = 12 or higher

Make the CONFIGURED_LINK_SETTINGS be the same for all link masters on the segment. The values for the fields of the CONFIGURED_LINK_SETTINGS on the Rosemount transmitter are (in order): 10, 6, 5, 37, 0, 12, 186, 2, 1, 0, 4

If you are still experiencing difficulties, you may want to try setting the interface card's PRIMARY_LINK_MASTER_FLAG parameter to FALSE.

National Instruments FP-3000 
The FP-3000 revision 2.3.5 (or earlier) Fieldbus H1 Network Module is also a link master device. With the default network parameter settings, they do not appear or work properly in NI-FBUS Configurator 2.3.6 (or later). The user needs to change the default settings of the fieldbus interface device.

T1 = 262144
T2 = 262144
T3 = 196608 (1/32 ms)
Slot Time = 5

After FP-3000 revision 2.3.6, the default network parameter settings will be compliant with Fieldbus Foundation recommended default values. The user does not need to change the settings anymore.

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