LACE instrument capacity

We are looking to expand our instrument resource and I am curious as to what the community has found regarding LACE performance with 4 instruments? Specifically we may find ourselves wanting to run 4 Agilent 1100 HPLCs per LACE where 2 of the LCs may have DAD detectors. I seem to remember a few years ago hearing that this may be an issue, i.e. only run 1 DAD per LACE. For reference we are running LACE config # 13 units, and Empower 3 FR2 SR2.An assumption would be that all 4 instruments would be running at once.


  • Do you have Agilent LCs on your LAC/E now?  I believe I was told that due to the Agilent ICF software, the system could only handle one Agilent LC per LAC/E.  Otherwise it would have communication issues, so that may be the limiting factor.

  • I was always told by Waters that one really should only run two instruments that are able to collect 3D data on a LAC/E. At the time we were running Waters instruments. The reason that I was given was communication problems on account of the high data volume required by the 3D detectors.

    If you want to mix and match you could do one PDA and two VWD's. The important factor being that each PDA counts as two instruments on the LAC/E.

  • Yep this pretty much what I was told years ago as well. I think I will assume this recommendation has not changed and advise accordingly. Looking forward to imaging/installing/qualifying a brand new LACE yummy!

  • You may wish to review this document as well, "Supported PDA detector data rates with Empower software"

  • My recommendation is to have no more than 2 instruments on 1 LACE. If you ever have to reboot the LACE for any reason, having fewer instruments on it would increase the likelihood of the LACE being idle.

  • It is interesting that GPIP throughput is between 1 and 8 MB/sec.  Current generations of instruments support Ethernet at 100 MB/sec on the instrument side.  Therefore, each LACE theoretically should be capable of supporting additional instruments and not limited to 4 TUV or 2 PDA.  Can Waters technical support comment?
  • Newer PDAs can sample at 80-200Hz depending on the vendor & model. If end users are not particular about avoiding the generation of excessively large data files, they may default to very high sampling rates across large patches of the spectrum (like 200-400nm). Worst case, that's 200 spectra x 200Hz x whatever the bandwidth/resolution is set to. That could mean 200x200x200/1xseconds per injection (48MILLION data points per minute)!
     I would never put more than 2 such detectors on a single LACE. If possible, I try not to have more than 2-3 instruments per LACE in general just so that fewer instruments are down in the event of a LACE failure, and in a pinch, we can drop a new instrument onto a particular bench quickly and add another LACE later (because not every author of a capital purchase req. is as careful about worrying about such things). I also try to keep at least one "spare" LACE around. This is/was for a lab w/ 50 active LACEs supporting just over 100 physical instruments and about 25 additional configurations among them.

    PS - I use same rules for Agilents using ethernet as for Waters systems. Multiple Agilents - not a problem... unless you want more than 2 DADs.
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