Model VME-SG 2
VME Plug-in Card Synchronized Generator
The Model VME-SG 2 is a 6U, VME compatible circuit card designed to supply precise time to a VME based computer. The board operates as a stand-alone generator or it may be synchronized to an external IRIG reference. BCD time, microseconds through years, is supplied to the computer bus. In the stand-alone mode, the generator time can be preset by the user and started and stopped under software control.
Time and status information is available to the VME com-puter bus in five, packed, 16 bit, BCD words. Since no time ready flags must be set before time information can be read, the time data is available with zero latency. On- board DIP switches select the memory address space where the board resides.
Two independent time freeze registers provide time on request from the VME bus, or in response to an externally generated pulse. The rate generator can be configured to output a pulse and produce interrupts at selected intervals. Four independently programmable interrupts are available and each has software selectable priority. The dual time compare feature can generate output pulses and interrupts with microsecond resolution. In the stand-alone mode generator time is preset and started and stopped under software control.
The IRIG B Code Generator provides the capability to generate and output both 1 kHz amplitude modulated IRIG B and IRIG B using RS-422 levels. This feature enables the VME-SG 2 to act as a timing source for remote displays, tape recorders, and other time code equipment in locations where IRIG B is not otherwise available.
The front panel display option provides time, date, position and operational status to the user. The display consists of four lines of high intensity LED alphanumeric characters and a push-button select switch.
If a long cable run is required between a VME master and slave the RS-422 IRIG B sync generator mode will provide excellent time transfer accuracy.