The Analog IO Board (TCQA) scales and conditions many of the analog signals read in by terminal boards mounted on the I/O cores <R1>, <R2>, and <R3>. These signals include the LVDT inputs, servo valve outputs, thermocouple inputs, 4-20 mA inputs and outputs, vibration inputs, relay driver outputs, pulse inputs, voltage inputs, and generator and line signals. Some of the signals are written to the STCA board via the 3PL connector. The generator and line signals are exchanged with the TCQC board via the JE connector. 4-20 mA input signals such as the fuel flow pressure and compressor stall-detect signals are scaled and conditioned on the TCQA board.
The I/O configuration screens are arranged within the I/O Configurator in this hierarchy:
Each I/O board shown has several associated screens.
These screens are duplicated if the I/O board is used more than once in the controller.
The following sections show the sample screens for each I/O board type, with a description of the screen following.
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Note： Numbers in the format (1) are used as callouts on the sample screen. The description for that callout
is below the screen.
Pulse Rate Input Circuit
The TCQA board contains the circuitry that scales and conditions the pulse rate inputs read from the TCQC board via the JE connector. These signals originate from the TTL (transistor to transistor logic) and magnetic pick up inputs whose signals are brought into the QTBA and/or PTBA terminal boards. The <R1> core receives the high pressure shaft speed inputs. The pulse rate input circuits on <R2> and <R3> may be used for other signals.
TCQA 4-20 mA Input Circuits
The TCQA board provides the circuitry for the 4ñ20 mA and 0ñ1 mA input signals.
The signals are read from the TBQC terminal board via the JB connector. The transducer current is dropped across a burden resistor and the voltage drop is read by the TCQA board and written to the I/O Engine via the 3PL connector. Hardware jumpers on the TBQC terminal board are used to select the current range of the input signals.
TCQA 4-20 mA Output Circuit
The TCQA board provides the circuitry for driving 4ñ20 mA outputs to the TBQC terminal board via the JB connector. These signals are typically used to drive control devices.
TCQA Thermocouple Circuit
Thermocouples are connected to the TBQA terminal board. Circuits also located on the TBQA terminal board provide the thermocouple cold junction reference, which are used by TCQA to calculate the cold junction compensation. The TCQA board uses the thermocouple input and compensation value to calculate the actual temperature read by the thermocouple. The I/O Engine reads the value via the 3PL connector. Thermocouple types and curves are selected using I/O configuration constants.
TCQA LVDT/R Circuit
Linear Variable Differential Transformers (LVDT) or Linear Variable Differential Reactors (LVDR) are used to detect the position of actuators. The position signals are read from the TBQC terminal board via the JF connector. The scaled and conditioned signals are used by the Control Sequence Program (CSP). The excitation signals for the LVDT/Rís are written to the QTBA terminal board via the TCQC board.
The LVDT/Rís are typically used for regulating servo valve outputs.
TCQA Seismic Vibration Circuit
The seismic vibration sensors are terminated on the TBQB terminal board in <R2> and <R3> and read by the TCQA board of the <R1> and <R3> cores respectively. The signals are scaled and conditioned and written to the Control Engine to be used by the CSP for monitoring and protection. Scaling values are selected in the I/O Configurator on the operator interface.
TCQA Generator And Line Circuit
In the <R1> core , the generator and line feedback signals from the Turbine Trip
Board (TCTG) pass to the TCQC board through the TCQA board via JD and JE connectors .
