ABB IMFEC12 Analog Input Module
The IMFEC12 module interfaces to conventional transmitters and standard analog inputs. It links process data and commu nication from field devices to all multifunction processors(MFP), or the IMMFC03, IMMFC04 and IMMFC05 multifunc tion controller (MFC) modules. The IMFEC12 module can be used as a direct replacement for the IMASI02 module; however,baseband communications are not supported.
The IMFEC12 High Level Analog Input (FEC) module inputs 15 channels of analog signals only to the multifunction processor(MFP) or multifunction controller (MFC) module.
The IMFEC11 High Level Analog Input (FEC) module inputs 15 channels of analog or frequency shift keyed (FSK) digital sig nals to the MFP or MFC module.
The IMFEC11 module per forms all the functions of the IMFEC12 module and also provides communication with the Bailey-Fischer & Porter line of FSK digital smart transmitters and other smart devices in a field bus or point-to-point configuration.
Figure 1-1 shows how the FEC module fits within the INFI 90
OPEN system
Installation and application personnel should have a solid background in electronic instrumentation and process control.
They should be familiar with proper grounding and safety pro cedures for electronic instrumentation. Operators should have a knowledge of the process and should read and understand this instruction before placing the module in operation.
The FEC module is an intelligent module, with on-board micro processor, memory, analog-to-digital converter and communi cation circuitry. The module is a single printed circuit board that occupies one slot in a module mounting unit (MMU). Two captive latches on the module faceplate secure it to the module mounting unit.
The module has three card edge connectors for external signals(transmitter inputs and communication), system communica tion (I/O expander bus) and power. The module receives input
through a cable connection to a termination unit (TU) or termi nation module (TM). Wiring from the field devices connect to terminal blocks on the termination unit or termination module.
The IMFEC11 circuit board has 18 jumpers; three jumpers that allow selecting the mode of operation and communication(J2, J3 and J4) and 15 jumpers that select voltage/current input (J6 through J20). A dipswitch setting (S1) holds the I/O expander bus address of the module.
This section explains the operation of the IMFEC1 Analog Input Module (FEC). The module does two major tasks. It provides an interface by which the controlling module (multifunction processor or multifunction controller module (MFP/MFC)can input analog process data from external devices or smart transmitters. It also serves as a communication link between the INFI 90 OPEN control system and field devices.
The IMFEC12 module accepts inputs from conventional trans mitters (BC, EQ and PT) and standard analog inputs of 4 to 20 milliamps, 1 to 5 VDC, 0 to 1 VDC, 0 to 5 VDC, 0 to 10 VDC and -10 to +10 VDC. The IMFEC11 has all the functionality of the IMFEC12 module but also provides FSK communications for interface to Bailey-Fischer & Porter smart transmitters and other smart devices
Upon receiving initialization from the controlling module(MFP/MFC), the FEC module stores that information in memory and checks the configuration of each input channel. If all input channels check good, operation begins. If the FEC module detects a configuration error, that error appears in the module status report.
Under normal operation, the controlling module sends trans mitter commands and requests process input data and status information from the FEC module.
The FEC module continu ously reads each input channel, does the necessary conver sions and stores the data in memory. When the controlling
module makes a request for data, the FEC module sends it the most current information that it has in memory.
If a communication failure with one of the transmitters occurs,the FEC module works to restore communication while continuing normal operation. It checks the transmitter configura tion upon restoring transmitter communication and normal process control continues.
The on-board microprocessor and control logic coordinates module functions. The microprocessor has four main functions:
• Storing the digital data in random access memory (RAM).
• Coordinating analog-to-digital conversion through the ana log-to-digital control chip.
• Preparing digital commands to send to the smart transmitters (IMFEC11 only).
• Reading and sending data to the controlling module (MFP/MFC).
The microprocessor directly links to eight kilobytes of random access memory. This memory serves as a storage area for process data and transmitter configuration information.
The microprocessor coordinates analog-to-digital conversions through ADC circuitry. The microprocessor takes the converted process data it receives from the ADC circuitry and
places it into a memory buffer. It remains in memory until the controlling module makes a request for process data or the microprocessor updates it with a new value.
When the micro processor receives a request for process data, it transfers that data from the memory buffer to a first in first out (FIFO) shift register where the controlling module can access it through the I/O expander bus interface.
For IMFEC11 modules (FSK communications), the micropro cessor sends command signals to the transmitters through the module communication circuitry. The circuitry converts com mands from the microprocessor into FSK signals. The micro processor directs the command transmission to the proper channel.
The MFP module communicates with the FEC module over the I/O expander bus. An Elsag Bailey designed integrated circuit interfaces the microprocessor to the I/O expander bus. All MFP commands and process data pass through the I/O expander bus interface and first in first out inputs or outputs.
