Teledyne API T703/T703U Calibrator Operation Manual Principles of Operation
185
The CPU includes two types of non-volatile data storage: a Disk on Module
(DOM) and an embedded flash chip.
Disk On Module (DOM) 9.2.2.1.
The DOM is a 44-pin IDE flash chip with a storage capacity up to 256 MB. It is
used to store the computer‟s operating system, the Teledyne API firmware, and
most of the operational data.
Flash Chip 9.2.2.2.
This non-volatile, embedded flash chip includes 2MB of storage for calibration
data as well as a backup of the calibrator‟s configuration. Storing these key data
onto a less frequently accessed chip significantly decreases the chance of data
corruption.
In the unlikely event that the flash chip should fail, the calibrator will continue to
operate with just the DOM. However, all configuration information will be lost,
requiring the unit to be recalibrated.
RELAY PCA 9.2.3.
The relay board is one of the central switching and power distribution units of the
calibrator. It contains power relays, valve drivers and status LEDs for all heated
zones and valves, as well as thermocouple amplifiers, power distribution
connectors and the two switching power supplies of the calibrator. The relay
board communicates with the motherboard over the I
2
C bus. Its status indicators
and components can be used for troubleshooting power problems and valve or
heater functionality.
Generally, the relay PCA is located in the right-rear quadrant of the calibrator and
is mounted vertically on the backside of the same bracket as the instrument‟s DC
power supplies, however the exact location of the relay PCA may differ from
model to model.
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