Liebert DS Modbus Comms

[crab master]

You had iCOM DS units with 485 cards speaking modbus right?

Yes

The good news is they are still working on it and may have found the smoking gun for this whole problem. I'm not really privy to the details.

I hope so cause I am tired of complaining about this and the local dealer and vendor are both saying I am the only one....It's nice to have this forum though, cause I hate it when they say such acting like it is a problem with our BMS and not theirs...

On the other items I will have to log in and look.

[krac]

Looking to start/stop some new Liebert DS units with factory installed Modbus rs-485 intellislot cards from a Jace and little confused how to mapp the registers that only have a coil number.
From the docs
Data Point Status Coil Bits
VSD Fan speed 10022 22 1
Unit Control - 25 1
Reset Alarm - 26 1
Acknowledge Alarm - 27 1

Coming up blank on adding coil only points to a Jace Modbus network.

[MaxBurn]

http://www.emersonnetworkpower.com/e...s/SL-28170.pdf

That should be the points list. I don't see those on a DS.

[krac]

Page 12 has the unit control point listed, but no status register just a coil number.

[MaxBurn]

If I am not mistaken function code 5 is force single coil, use that for those points 25-37. For the status on those they are elsewhere in the points list where they can send a large number or where more appropriate for alarms etc.

[krac]

Looks like it maps to a normal Boolean Writable. The unit I was testing had been stopped locally so the remote start doesn't work which is consistent with the older System 3 control. For some reason the Local Off point (Reg 30100) is not changing state but I can deal with that later.

Thanks for the help Scott.

[krac]

Having another issue with finding the Modbus register for the chilled water valve position. The documentation only shows Compressor Utilization (30104) but that point faults when mapped into AX.
Every other point seems to behave as expected.

[MaxBurn]

I think you are looking for something like percent cooling and possibly stages? Pretty sure one of those reflects valve percent on CW units.

[krac]

Liebert Tech support confirmed that I should use register 30104 which is listed as Compressor Utilization, however that point faults when I map it into the Jace. When it didn't work I mapped in a bunch of the registers from 30102 up to 30114 just to see I could find it.