Section 2
2.1
OPERATION
The
IF303
accepts signals from mA generators such as most conventional transmitters. It is
therefore ideal for interfacing existing equipment to a Fieldbus system.
Functional Description – Electronics
See Figure 2.2 - IF303 Block Diagram. The function of each block is described below.
MUX Multiplexer
The MUX multiplexes the input terminals to ensure that all three channels reach the A/D converter.
A/D Converter
The A/D converts the input signals to a digital format for the CPU.
Signal Isolator
Its function is to isolate the data signal between the input and the CPU.
(CPU) Central Processing Unit, RAM and FLASH
The CPU is the intelligent portion of the converter, being responsible for the management and
operation of block execution, self-diagnostics and communication. The program is stored in Flash
memory. For temporary storage of data there is a RAM. The data in the RAM is lost if the power is
switched off, however the device also has a nonvolatile EEPROM where data that must be retained
are stored. Examples of such data are: calibration, configuration and identification data.
Communication Controller
It monitors line activity, modulates and demodulates the signal from network line.
Power Supply
Takes power of the loop-line to power the converter circuitry.
Power Isolation
Just like the signals from the input section, the power to the input section must be isolated.
Display Controller
Receives data from the CPU and drives the Liquid Crystal Display.
Local Adjustment
They are two switches that are magnetically activated. They can be activated by the magnetic tool
without mechanical or electrical contact.