Support simultaneous Computrainer + ANT - want to use ANT/Powertap for my Power/Cadence and still control the Computrainer normally

I want to use my Powertap for power data because the computrainer underreports efforts in the 700-1000W range by up to 100W, but the two match almost exactly for efforts under 500W.

I thought no problem I’ll just hook up an ANT USB stick and select the powertap for my Power.

Unfortunately this does not work, when I do this and select Computrainer for speed and HR, it says ‘no signal’ and also when I attempt to ride, the Computrainer is not put in program control mode i.e. Zwift is not controlling it for adjusting the resistance etc.

What I’d like is for Zwift to support using the Computrainer but allowing the user to choose their source of data input for Power/Speed/HR/Cadence to whatever instruments they like that are hooked up via ANT.

They are doing it for the kickr,

It might be coming for the CT too.

While you can use any mix of cadence and power devices, I don’t believe you can use a Powertap (or Quark, in my case) to control a Kickr or CT. It would be nice, however.

I don’t think he wants it that way. Like I wish my kickr was in line with my quarq but it’s not. The wattage is very different. I want to see my quarq power but get the erg/ resistance in the kickr

To be clear, I don’t necessarily care if the Powertap controls the Computrainer, i.e. don’t want it to be part of the control loop that influences the change in load/resistance, though if it did that accurately that would be fine but it’s not necessary. The bit that’s important to me is that the sim use the power readings from the Powertap for the purpose of what’s happening to my rider in the simulator, to determine the watts input that drive the physics in the game and to be what’s shown on the in-game display, what contributes to the watts/kg reading, and what gets saved for power in the .fit file. My situation does sound a lot like the kickr/quark issue that Allan linked to.

That’s clearer. Thanks Allan and Eric. I don’t believe actual cadence is used at all by Zwift for simulation performance, so cadence is different from power in that respect.
You’re sort of asking for two simulations. One of the screen rider based on the Powertap, and the other of your actual ride based on the CT. That could make for a strange ride if the powers vary by a lot.
I can understand wanting to use the Powertap power to control both the CT and the screen rider because the Powertap readings are what you will see out on the road. I would like to see that as well. Also, it seems like that would be easier to implement.