1.1. Is there a trigger output available, so I can synchronize external devices with the DLC pro?

Yes, indeed!

There is a digital I/O connector at the rear of the MC/MC+ module of the DLCpro that can be used to obtain, for example, trigger signals for the piezo scan (DLpro or CTL) or the motor scan (for the CTL laser).
More information can be found in chapter 9.2.3 / 9.2.4 of the DLCpro user manual. 

1.2. Are there any sample VIs that illustrate how to address the DLC with LabView?

An example for how to send commands to the DLC pro using LabView is available for download from DLC pro web page, download section. It is also included on the USB drive that is delivered with the system, as well as with any firmware update package.

1.3. What do the numbers for the different output channels mean?

This information is now part of the command reference that can be found on the USB drive that is delivered with every system. If you have an older version, please refer to the list below, or download the latest firmware release package from the DLC pro web page, download section (see Documentation folder).

If one has a dual-laser-option the output channel-number for laser 1 and laser 2 have the same nomenclature.

["None", -3]

["Fine In 1", 0]
["Fine In 2", 1]
["Fast In 3", 2]
["Fast In 4", 4]

["Out A", 20]
["Out B", 21]

["CC Current", 51]
["CC Aln1", 52]
["CC Aln2", 53]

["PC Voltage", 50]
["SC Output", 101]

["Laser PD", 54]
["External Power", 55]
["PowerLock Input", 102]
["Lock Input", 100]
["Lock-In Output", 30]
["PID 1 Output", 31]
["PID 2 Output", 32]

Only TApro
["Amp. Current", 63]
["AMP Aln", 60]
["Seed Power", 61]
["Amp. Power", 62]

Only DLC CTL
["CTL Power", 70]

Only DLC DL-/TA-SHG/FHG pro
["SHG PC Voltage", 90]
["Seed Power", 85]
["Amp. Power", 84]
["SHG Power", 83]
["Fiber Power", 86]

Only DLC DL-/TA-FHG pro
["FHG PC Voltage", 120]
["FHG Power", 113]