IOSCommLogic V+ Design

feature author: Paul Halliday

The IOSCommLogic worksheet is split into two parts and shown in Figure 47 and Figure 48. The first part is the logic for the Instructor. The second part is the logic for the Observer. At the top of the first part is a DSP output port labeled IOS Headset Master. A constant 1.0 is wired to it that enables the IOS headset at all times.

There is one input coming from the host called Instructor Transmit Selector. This is wired to two One of Eight Selector objects. Each of these selectors only deals with input values of 1, 2, or 3 (Pilot, CoPilot, or Both). The other five selector pins are shunted to No Connection objects. Now let’s look at the logic for the first selector. We used two Logical OR objects to perform the following logic.

if (instructor_tramsit_selector == PILOT) OR (instructor_tramsit_selector == BOTH)

{

   set IOS Mic to Pilot Headset = 1.0

   set transmitting = TRUE

}

else

{

   set IOS Mic to Pilot Headset = 0.0

   set transmitting = FALSe

}

if (instructor_tramsit_selector == COPILOT) OR (instructor_tramsit_selector == BOTH)

{

   set IOS Mic to CoPilot Headset = 1.0

   set transmitting = TRUE

}

else

{

   set IOS Mic to CoPilot Headset = 0.0

   set transmitting = FALSE

}

The outputs of these Logical ORs are then wired to another OR , which then feeds a 1 of 2 Selector object. There are two Constant Float objects wired to this object. The first, labeled LOW has a value of  0.5, and the second, labeled HIGH has a value of 1.0. If the control pin is FALSE, the LOW value is passed to the output IOS Mic Sidetone. If the control pin is TRUE, the HIGH value is passed to IOS Mic Sidetone. Another way to look at it is as follows.

if (transmitting == TRUE)

   set IOS Mic to IOS Headset = 1.0

else

   set IOS Mic to IOS Headset = 0.5

The second One of Eight Selector is used to transmit the Instructor’s mic signal to the Pilot and CoPilot’s overhead speakers.  Two more inputs are added to the logic. They are the Pilot Audio Speaker and CoPilot Audio Speaker worksheet connectors from the PilotCommLogic and CoPilotCommLogic designs. These inputs and the results of the Logical OR objects are ANDed together to feed the Instructor’s mic signal to the appropriate overhead speaker. Here’s the textual logic.

if (pilot_audio_speaker_switch == ON) AND

   ((instructor_tramsit_selector == PILOT) OR (instructor_tramsit_selector == BOTH))

   set IOS Mic to Pilot Overhead = 1.0

else

   set IOS Mic to Pilot Overhead = 0.0

if (copilot_audio_speaker_switch == ON) AND

   ((instructor_tramsit_selector == COPILOT) OR (instructor_tramsit_selector == BOTH))

   set IOS Mic to CoPilot Overhead = 1.0

else

   set IOS Mic to CoPilot Overhead = 0.0

At the bottom of Figure 47 are small models to allow the Instructor to always hear both pilots. They use the worksheet Input Worksheet Connector objects Pilot Mic Hot and CoPilot Mic Hot from the PilotCommLogic and CoPilotCommLogic designs. These are fed into a 1 of 2 Selector. If a mic is hot, meaning a pilot is transmitting, then the signal strength of that mic is fed to the instructor headset with a value of 1.0 Otherwise, the value is 0.5, like sidetone.

Figure 47.  IOSCommLogic Design (Instructor)

The Observer part of the IOSCommLogic design is pretty simple. First, we enable the headset and set a constant sidetone from the Observer’s mic to the Observer’s headset. Then we feed the Observer’s mic to the Instructor’s headset, and the Instructor’s mic to the Observer’s headset at a constant signal value of 0.5. At the bottom of the Observer’s design is logic similar to that found at the bottom of the Instructor’s design. The Observer will also hear the pilots at a higher volume when they are transmitting, and hear them at a sidetone level when they are not.

Figure 48.  IOSCommLogic Design (Observer)