Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller Instruction Manual - Manual (Page 86)

3.4 CONTROLLER POWER SUPPLY
The internal power supply provides power to the Main Board, Expansion Board with its installed
option cards, display, and output power for transmitters (24-26 V dc, 80 mA total available output for
controller and transmitters).
3.5 MAIN PRINTED CIRCUIT BOARD
The Main Board contains the necessary circuitry, firmware, and memory for 53MC5000 Process
Control Station functionality.
A microprocessor provides the intelligence to perform the various processing and calculation algo-
rithms. For improved reliability, surface-mount technology is used in the design. The microprocessor
controls the display, keypads, configuration port communications, Datalink communications, analog
input/output signals, digital input/output signals, and options interface. The main printed circuit board
contains circuitry to protect against various fault conditions on the base I/O. It also contains the base
product analog-to-digital and digital-to-analog signal conversions, as well as timers.
3.6 EXPANSION BOARD
The Expansion Board has five slots that allow a variety of optional hardware cards to be added
internally to the controller to extend its basic input/output (I/O) capabilities. The option cards contain
the operating instructions specific to that option and each option card can access main memory
directly. All signal synchronization between options cards is provided by the Main Board Processor-
I/O. Five typical option cards that can be configured in an expansion ready controller are the 6 Digital
Input/4 Digital Output (6DI/4DO) PCB Option, 16 Digital Input/Digital Output (16DI/DO) PCB Option,
Single Channel Analog Input PCB Option, Multi I/O Analog PCB Option, and High Speed Communi-
cations PCB Option. Some of these options are mutually exclusive, as they can not cohabit the same
Expansion Board slot. These options cards are illustrated and described in detail in Section 18,
Maintenance and Parts List. Additional option cards, such as the Auxiliary Processor Board (APB),
which is not listed here, may also be added to the controller. The additional option cards are
described in the documentation that is shipped with the option.
3.7 SAMPLING TIME INTERVALS
Analog and digital input signals are sampled 20 times a second (every 50 ms). These signals are
converted if needed and digitally processed to provide the required filtering. At configurable SCAN
INDEX intervals between 1 (50 ms) and 30 (1500 ms or 1.5 seconds), the signals are further
processed to convert them into engineering units and calculations are performed to obtain the
needed results. After the calculations are completed the results are converted and used to update
the analog and digital outputs with new values.
There are eight trend and eight totalizing operations that occur within a one second time frame. One
trend or totalizer is updated every 50 ms. Trends are processed first, then totalizers, in ascending
order. Although the 16 operations at 50 ms each do not fill one complete second (200 ms less than
a second), each trend and totalizer is updated once every second.
The data update rate for the display is configurable as the BACKGROUND SCAN INDEX. The
BACKGROUND SCAN INDEX is a function of the SCAN INDEX. The [(BACKGROUND SCAN
INDEX) X (SCAN INDEX) X (50 ms)] = DISPLAY DATA UPDATE TIME INTERVAL.
Section 3. Product Description
3-3