Detcon 700 Foundation Fieldbus Bridge - Manual (Page 7)

Foundation Fieldbus Bridge
700 Sensor FF Bridge IM Rev. 0.0 Page 3 of 8
3.0 Operation
When power is applied to the Foundation Fieldbus Bridge with the Model 700 sensor attached, the FF Bridge
will go through a boot up sequence that will last for approximately 10 seconds. After the boot up sequence the
FF Bridge will enter normal operation, and communication with the Host will begin. A green LED Labeled
“Fieldbus” on the FF Bridge will illuminate when the FF Bridge is communicating with the Foundation
Fieldbus Host.
A green/yellow LED labeled “Modbus” will illuminate green each time the FF Bridge polls the Model 700
sensor over the Modbus. The “Modbus” LED will illuminate yellow each time the Model 700 sensor responds
to a poll from the FF Bridge.
3.1 Function Block Model
The Foundation Fieldbus Bridge function block model includes a resource block (RB), a transducer block (TB)
and four analog input blocks (AI). The resource block defines parameters that apply to the entire device.
These include the manufacturer ID, device type, and software revision.
The transducer block contains four primary variables that indicate the status of the Model 700 sensor (see
Section 3.2). It also contains all of the parameters required to establish Modbus communication with the
Model 700 sensor. All of these parameters are set by the Detcon factory and do not need to be configured by
the user. The Modbus parameters are write-protected to prevent accidental changes to the settings.
A screen shot of the Modbus settings is shown in Figure 3. This screen shot is taken from the National
Instruments NI-FBUS Configurator application. The format of these settings may vary depending on the
application used to view them. The value of the settings should always be as shown in Figure 3.
The Modbus address on the Model 700 sensor must be set to ‘1’ for the Foundation Fieldbus Bridge to
operate correctly.
The Model 700 sensor address will be set to ‘1’ by the Detcon factory when it is shipped
with a Foundation Fieldbus Bridge installed. If the Foundation Fieldbus Bridge is being installed in a
previously purchased Model 700 sensor, the user will need to ensure that its Modbus address is set to ‘1’.
Refer to the manual for the Model 700 sensor for instructions on setting the sensor’s Modbus address.
The four Analog Inputs Blocks (AI) in the Foundation Fieldbus Bridge take each primary variable and make it
available to other function blocks as its output. The functionality in AI blocks is not currently used and these
blocks are not configured prior to shipment from the Detcon factory. Please contact Detcon Technical Support
if the AI blocks are needed for your application.