Principles of Operation Teledyne API T703/T703U Calibrator Operation Manual
190
External Digital I/O 9.2.4.5.
The external digital I/O performs two functions.
The STATUS outputs carry logic-level (5V) signals through an optically isolated
8-pin connector on the rear panel of the calibrator. These outputs convey on/off
information about certain calibrator conditions such as CONC VALID. They
can be used to interface with certain types of programmable devices.
The CONTROL outputs can be used to initiate actions by external peripheral
devices in conjunction with individual steps of a calibration sequence (see
Section 6.5.1.6).
The CONTROL inputs can be initiated by applying 5V DC power from an
external source such as a PLC or data logger (Section 6.5.1.5). Zero and span
calibrations can be initiated by contact closures on the rear panel.
I
2
C Data Bus 9.2.4.6.
I
2
C is a two-way, clocked, bi-directional, digital serial I/O bus that is used widely
in commercial and consumer electronic systems. A transceiver on the
motherboard converts data and control signals from the PC-104 bus to I
2
C. The
data is then fed to the relay board, optional analog input board and valve driver
board circuitry.
Power-up Circuit 9.2.4.7.
This circuit monitors the +5V power supply during calibrator start-up and sets the
analog outputs, external digital I/O ports, and I
2
C circuitry to specific values until
the CPU boots and the instrument software can establish control.
POWER SUPPLY AND CIRCUIT BREAKER 9.2.5.
The calibrator operates in two main AC power ranges: 100-120 VAC and 220-
240 VAC (both ± 10%) between 47 and 63 Hz. A 5 ampere circuit breaker is
built into the ON/OFF switch. In case of a wiring fault or incorrect supply power,
the circuit breaker will automatically turn off the calibrator.
NOTE:
The calibrator is equipped with a universal power supply that allows it to accept any AC power
configuration, within the limits specified in Table 2-2.
CAUTION
Should the power circuit breaker trip, correct the condition causing this situation
before turning the calibrator back on.
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