There are a few reasons you might want to collect data with both a Motion Encoder and a photogate at the same time. One example is for studying collisions. Since the Dynamics Cart and Track System with Motion Encoder comes with only one Encoder Cart, you can use a photogate with a Cart Picket Fence to record the speed of the non-encoder plunger cart. (Using a motion detector instead of a photogate is another option.)

Instructions for using Logger Pro 3
Related Parts
Dynamics Cart and Track System with Motion Encoder (DTS-EC)
Photogate (VPG-BTD)
Cart Picket Fence (PF-CART)

Connect the Vernier Photogate and Motion Encoder Receiver to the digital ports of a LabQuest interface (any model). Be sure to connect the Motion Encoder Receiver to DIG 1 and the Photogate to DIG 2. Connect the LabQuest interface to a computer running Logger Pro 3. Adjust the parameters for the photogate to match the experiment. In Sensor Setup, click on the Photogate and choose Set Distance or Length. Then set it to Cart Picket Fence, if that is what you are using.

Instructions for using LabQuest App with a Vernier Photogate (VPG-BTD)
Related Parts
Dynamics Cart and Track System with Motion Encoder (DTS-EC)
Photogate (VPG-BTD)
Cart Picket Fence (PF-CART)

If you use a LabQuest as a standalone device, you must use time-based data collection. From the Photogate Mode setup within the Time Based dialog select Gate timing. Adjust the Length of Object as needed to match the Cart Picket Fence, if that is what you are using.

Instructions for using Graphical Analysis, Graphical Analysis Pro, or LabQuest App with a Go Direct Photogate (GDX-VPG)
Related Parts
Dynamics Cart and Track System with Motion Encoder (DTS-EC)
Go Direct® Photogate (GDX-VPG)
Cart Picket Fence (PF-CART)

Graphical Analysis and Graphical Analysis Pro
• Connect the Motion Encoder receiver to a LabQuest interface
• Launch Graphical Analysis then connect the interface and a Go Direct Photogate

LabQuest App (original LabQuest is not supported)
• Connect the Motion Encoder receiver
• Connect the Go Direct Photogate via USB or wireless Bluetooth connection

The default time-based collection will work for this experiment. If necessary, adjust the experiment duration to ensure you are collecting the desired data.

Note: You cannot collect data with a Motion Encoder and a Vernier (BTD) Photogate simultaneously using Graphical Analysis or Graphical Analysis Pro.

How do I use two motion detectors or two motion encoders at once to study collisions?
Vernier Photogate (VPG-BTD) Troubleshooting and FAQs
Motion Encoder System Troubleshooting and FAQs