Page 22 2000-1252-01 Released Rev. C
VersaPort 2200 Technical Manual
Chapter 2: Theory of Operation
VersaPort Components
a
Any over-current situation is detected via a sense resistor. If a 24v current greater than
5.0 amps nominal is detected, the transistor power switch will turn off or will be tripped. If
the switch is tripped, 24v power must be shut off and then turned on to reset the
VersaPort.
A second over/under voltage circuit is used to detect a power failure and signal the CPU.
The acceptable range for this circuit is from +22.8v to +26.4v (nominal). This voltage is
within the range of the first over/under voltage circuit, described above. Voltage outside
the acceptable range gives a power fail signal, which allows for orderly shutdown of
motors and the saving of certain run-time parameters and data to the battery-backed
static random access memory (SRAM). Data is saved before transistor power is switched
off, as described in the previous paragraph.
The +24v switch voltage from the transistor power switch provides power for the
motor-driver circuits and the dc-to-dc converter. The converter provides +5v to the digital
circuitry and ±12v for analog and interface circuitry.
CPU
The CPU microprocessor is the 80C188. This processor provides a 16-bit internal and
8-bit external data transfer bus running at 16 MHz.
Program Memory
The program memory is contained in an erasable-programmable random access memory
(EPROM).
SRAM
The SRAM is battery backed to provide a long-term non-volatile random-access memory
(NOVRAM). This is a readable-writeable memory source for the storage of equipment
configuration data and history. The battery (Lithium type) is self contained in the
NOVRAM socket device and has an estimated shelf life of ten years.
Quad-Serial I/O
The quad-serial I/O device is a universal asynchronous receiver transmitter (UART) used
to process three channels of bi-directional RS-232 data.
• ASCII Host Equipment. A 9-pin D-subminiature type connector is for external
RS-232 connection of the Host computer or the Process Tool controlling the
system using ASCII communication.
• SECS Host. A 9-pin D-subminiature type connector for connection to the Host
computer or Process Tool using SECS I/II communication.
• MSC. A 9-pin D-subminiature type connector for external RS-232 connection of a
MicroStation Controller, for communication with an external computerized system
to control and/or monitor SMIF and SMART-Traveler components.
• RFID (Optional). A 9-pin D-subminiature type connector is for external RS-232
connection to the Master Controller for the RFID system.
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