- Emerson Remote Terminal Unit Instruction Manual

CI-ControlWave Express Introduction / 1-5
will remain on. When interfaced to a keypad, the operator may activate the display at any
time by pressing the appropriate front panel button.
1.3.2 CPU/System Controller Board
The multilayer CPU/System Controller Board provides ControlWave Express CPU, I/O
monitor/control, memory and communication functions. ControlWave Express CPU/System
Controller Boards operate over an extended temperature range with long-term product
reliability.
ControlWave Express CPU/System Controller Boards are based on a 32-bit ARM9TDMI
RISC Core Processor. The CPU/System Controller Board is specified to operate with an
input voltage range from a nominal +6Vdc, +12Vdc or +24Vdc power supply with a system
clock speed of either 14 MHz or 33 MHz. In addition to the microprocessor and control logic,
the CPU Board includes two fixed RS-232 communication Ports (COM1 & COM2), and one
configurable RS-232/RS-485 communication port (COM3). CPU Memory consists of 2MB of
battery backed Static RAM (SRAM), 512kB Boot/Downloader FLASH and 8MB
simultaneous read/write FLASH. Three unique CPU/System Controller Boards are offered
as follows:
• 14 MHz Ultra Low Power CPU: operates from a nominal +6Vdc or +12Vdc bulk input
power and is equipped with a Solar Regulator circuit and an Auxiliary Power Output
circuit.
• 33 MHz Low Power CPU: operates from a nominal +12Vdc or +24Vdc bulk input power,
is equipped with a Solar Regulator circuit and an Auxiliary Power Output circuit).
• 33 MHz Low Power CPU: operates from a nominal +12Vdc or +24Vdc bulk input power
and is equipped with a 10/100Base-T Ethernet Port. Note: Not equipped with a Solar
Regulator circuit or an Auxiliary Power Output circuit.
CPU/System Controller Boards are provided backup power via a coin cell socket that
accepts a 3.0V, 300mA-hr lithium battery. This 3.0V battery provides backup power for the
real-time clock and the system’s Static RAM (SRAM). Backup power is enabled when
Configuration Jumper W3 (adjacent to the battery) is installed in position 1 to 2.
If the 3.3Vdc that powers the unit goes out of specification, a supervisory circuit on the
CPU/System Controller Board switches the battery voltage to the VBAT3.3 hardware signal
(used by the CPU’s SRAM and RTC). This supervisory circuit also generates a
BATTERYGOOD signal when the battery voltage is above 2.35V.
The system SRAM is specified to have a standby current of 20:A maximum for each part
(plus 2uA for the RTC). For a system containing 2MB of system SRAM, a worst-case
current draw of 42:A allows a battery life of approximately 9000 hours.
The power supply operates from a nominal +6Vdc, +12Vdc or +24Vdc (depending on the
CPU type) with the nominal input supply configuration being user configured via on-board
jumpers. A supervisory circuit monitors the incoming power and the supply voltages. The
isolated supplies are shut down when the incoming voltage drops below +5.4V for a +6.0V
system, +11.4V for a +12V system or +21.8V for a +24V system.
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