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Posted

I'm just beginning a sim cockpit project and my first hardware addition will be the spolier/throttle/flaps mechanism for the B737-700.

I am running FS2k2 on Win XP with latest FSUIPC and PM software via wideclient.

My primary joystick is a CH ProPilot w/ rudder pedals (non-USB).

I disassembled my old MS sidewinder and recovered 3 pots and 2 switches wired to the gameport plug. I measured the pots at 100 kohm in full resistance position and 0 fully open. I used a RS USB gameport adapter to add this "joystick" to WinXP and FS2k2.

So far so good: FS2k2 recognized the 2nd device and I calibrated it via turning the pots manually. I assigned the X and Y pots to throttles 1 & 2 and the "slider" pot to mixture4_set. I then mapped mixture4_set (via its control# - 66431) to the FlapsSetControl in FSUIPC.ini and calibrated it in FSUIPC. I also calibrated throttles 1 & 2 in FSUIPC. I deleted the mapping of the single throttle in the CH yoke settings in FS2k2.

So here's the issue: the range of "action" on the pots is very limited (maybe 90 degrees) and does not appear to be linear as viewed on my ohm meter. When I delicately twist the pot stem for either throttle N1 shoots up like a rocket from 21% to 60% with miniscule pot movement. Likewise, flap detents are separated by tiny rotational distances on the flaps pot (though at least they do extend & retract ).

Here is the relevant section from FS2002.cfg:

[JOYSTICK_MAIN {E1AEA950-6B68-11D7-8001-444553540000}]

LOCKED=1

AXIS_EVENT_00=AXIS_THROTTLE1_SET

AXIS_SCALE_00=127

AXIS_NULL_00=1

AXIS_EVENT_01=AXIS_THROTTLE2_SET

AXIS_SCALE_01=127

AXIS_NULL_01=1

AXIS_EVENT_06=AXIS_MIXTURE4_SET

AXIS_SCALE_06=127

AXIS_NULL_06=0

and FSUIPC.ini:

[JoystickCalibration]

FlapsSetControl=66431

ReverserControl=66292

MaxThrottleForReverser=0

AileronTrimControl=0

RudderTrimControl=0

Aileron=-16383,-138,278,16383

Elevator=-16299,-280,0,16383

Rudder=-16383,-280,278,16383

Throttle=-16193,16192

Throttle1=-16380,-13067,-11816,16192

Throttle2=-16380,-11059,-10204,16192

Flaps=-14875,16192

How have people approached these difficulties? Should I toss the pots and get new ones with a longer scale (e.g. 100k 270 degree linear taper)? Are my scale and Null settings to blame? I read that in FS2000 with the flaps_set axis available one sets scale to 1 and null to 0 but that did not seem to hold true in the directions for FS2002. Or do you think eberything will work fine once I've actually mounted the pots and attached levers, etc?

Thank you for any help and guidance that you can provide!

Scott Fausel

Posted

I'm just beginning a sim cockpit project and my first hardware addition will be the spolier/throttle/flaps mechanism for the B737-700.

I am running FS2k2 on Win XP with latest FSUIPC and PM software via wideclient.

My primary joystick is a CH ProPilot w/ rudder pedals (non-USB).

I disassembled my old MS sidewinder and recovered 3 pots and 2 switches wired to the gameport plug. I measured the pots at 100 kohm in full resistance position and 0 fully open. I used a RS USB gameport adapter to add this "joystick" to WinXP and FS2k2.

So far so good: FS2k2 recognized the 2nd device and I calibrated it via turning the pots manually. I assigned the X and Y pots to throttles 1 & 2 and the "slider" pot to mixture4_set. I then mapped mixture4_set (via its control# - 66431) to the FlapsSetControl in FSUIPC.ini and calibrated it in FSUIPC. I also calibrated throttles 1 & 2 in FSUIPC. I deleted the mapping of the single throttle in the CH yoke settings in FS2k2.

So here's the issue: the range of "action" on the pots is very limited (maybe 90 degrees) and does not appear to be linear as viewed on my ohm meter. When I delicately twist the pot stem for either throttle N1 shoots up like a rocket from 21% to 60% with miniscule pot movement. Likewise, flap detents are separated by tiny rotational distances on the flaps pot (though at least they do extend & retract ).

Here is the relevant section from FS2002.cfg:

[JOYSTICK_MAIN {E1AEA950-6B68-11D7-8001-444553540000}]

LOCKED=1

AXIS_EVENT_00=AXIS_THROTTLE1_SET

AXIS_SCALE_00=127

AXIS_NULL_00=1

AXIS_EVENT_01=AXIS_THROTTLE2_SET

AXIS_SCALE_01=127

AXIS_NULL_01=1

AXIS_EVENT_06=AXIS_MIXTURE4_SET

AXIS_SCALE_06=127

AXIS_NULL_06=0

and FSUIPC.ini:

[JoystickCalibration]

FlapsSetControl=66431

ReverserControl=66292

MaxThrottleForReverser=0

AileronTrimControl=0

RudderTrimControl=0

Aileron=-16383,-138,278,16383

Elevator=-16299,-280,0,16383

Rudder=-16383,-280,278,16383

Throttle=-16193,16192

Throttle1=-16380,-13067,-11816,16192

Throttle2=-16380,-11059,-10204,16192

Flaps=-14875,16192

How have people approached these difficulties? Should I toss the pots and get new ones with a longer scale (e.g. 100k 270 degree linear taper)? Are my scale and Null settings to blame? I read that in FS2000 with the flaps_set axis available one sets scale to 1 and null to 0 but that did not seem to hold true in the directions for FS2002. Or do you think eberything will work fine once I've actually mounted the pots and attached levers, etc?

Thank you for any help and guidance that you can provide!

Scott Fausel

Posted

Thanks, Jose - yes I realized after some more research that the variable resistance is used indirectly to vary the voltage and THAT is what determines the scale.

I wonder if at least part of the issue is the resolution of the USB adapter - from what I hear the "bit depth" of its pseudo A-D converter is poor, and thus there are rather large gaps between the resultant output values sent to FS.

I'm going to try to run it directly into my PCI card gameport and see if there's a noticeable difference.

Still open for other suggestions!

Thanks!

How is the voltage variation? As far I know that's what counts not the resistance. If the Pot is a 3 point one you can try this solution:
Posted

Thanks, Jose - yes I realized after some more research that the variable resistance is used indirectly to vary the voltage and THAT is what determines the scale.

I wonder if at least part of the issue is the resolution of the USB adapter - from what I hear the "bit depth" of its pseudo A-D converter is poor, and thus there are rather large gaps between the resultant output values sent to FS.

I'm going to try to run it directly into my PCI card gameport and see if there's a noticeable difference.

Still open for other suggestions!

Thanks!

How is the voltage variation? As far I know that's what counts not the resistance. If the Pot is a 3 point one you can try this solution:

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