In theory USB supports up to 127 devices.
We recently had 12 sensors connected to StarLab, and it worked normally. The practical limitation is basically how many channels you can realistically see on the display (which would not be a limitation if you will only be logging the data), and of course the number of available USB ports/hubs.

All USB speaking devices (EA-1, Juno, Juno+, Pulsar and USBI as well as the StarBright, Centauri, Vega, Nova-II, and StarLite Power and Energy Meters) can be controlled via our StarLab. This provides full remote control and measurement capabilities. In addition, system integrators can make use of the OphirLMMeasurement COM object for all of our USB speaking devices that are included in the application installation. Documentation and Examples in Visual Basic, LabVIEW are found in the "Automation Examples" sub-directory of your StarLab directory.

Ophir periodically releases new versions of StarLab, adding new features and fixing bugs, so it's a good idea to keep updated with the latest StarLab version.

回答

For customers using the new LabVIEW COM Demo, there is nothing additional to do. Just open it and get started. If writing your own LabVIEW application, make sure that the OphirLMMeasurement COM Object is included in your LabVIEW application.

For customers using the legacy OphInstr LabVIEW package, here are additional clarification steps to assist establishing the interface to LabVIEW when connecting an Ophir meter such as the Juno/USBI/Nova II/Vega with the USB.

The sequence for preparing to interface the Ophir Juno (or meters connected through USB) with LabVIEW is generally as follows:

• Disconnect any Juno OPHIR Device from the PC
• Run SwapINF utility
• Set LabVIEW option On
• Press "Swap" button - You will be prompted to "Remove the Ophir Juno Devices before continuing" 
• Press "OK" (you have already removed these)
• Press "OK" again (after SwapINF is done)
• Reconnect the Ophir Juno device to the PC that you wish to apply LabVIEW VI's on If asked by Wizard (i.e. in XP) to update software etc.
• Select "not this time" & press "next" button
• Again, press "next" (install software automatically)

From here on you may apply LabVIEW VI's on your device.

See attached

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

Sometimes an application requires logging power from multiple power sensors, and being able to compare readings from the different sensors. In such cases, it is necessary to know to what degree the time points of each “channel” are in synch with each other.

Possible solutions would be to use a 2-channel Pulsar, or for example 2 Juno/Juno+.

With Ophir power sensors, the logged data timestamps originate from the PC, with millisecond resolution, for both Pulsar’s and Juno/Juno+.

So basically there is no difference between a Pulsar and a Juno/Juno+ in that respect. They will perform the same.

Each measurement will have its own separate timestamp, and will not have the exact same zero point. However, they will be ‘synced’ to each other to within a millisecond or so. Keep in mind that with power measurements, the instrument’s A/D sampling rate of the power signal is 15 Hz (i.e. every 66.67 msec), so for all practical purposes the 2 channels can be considered in synch with each other.