Suggestions for Industrial Power Monitoring

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zog said:
What type of breakers are they? You already may have most of what you need there.
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Zog;

Thanks for the reply!

The Gear is Siemens SB2, using the following Sentron Device Frames (MCCB):


  • Type ED Frames - for 100 Amp Circuits (125A Frame),
  • Type FD Frames - for 250 Amp Circuits (250A Frame),
  • Type LD Frames - for 400 Amp Circuits (600A Frame),
  • Type ND Frames - for 1200 Amp Circuits (1200A Frame).


No integral Monitoring Devices exist within these Breakers (I was hoping the devices might have provisions, but no luck!).

My plan is to use Square D's Enercept Meters, Serial connected via single pair STP with 600V Insulation (Belden 1120A), then connect the MODBUS Devices to the LAN (actually WAN) via an Ethernet Gateway.

There is an IDF at the Electrical Room, which allows me to use CAT5 copper for LAN connection to the Gateway - instead of running fiber to the MDF.

Again, thanks for the reply.

Scott
 
100714-1937 EST

Scott:

Are the RS-485s isolated, and what is total cable length?
Is Modbus a fixed baud rate? If not what rate are you using?

If high voltage was applied between the + and - signal lines and the 485 driver is destroyed, then how much else gets destroyed? If it is an isolated 485, then is it a sub module that is easily replaced? If isolated what is the isolation voltage rating?

From where do you derive power for the unit?

.
 
GAR;

Thanks for the reply.

I'll address each item below:


Are the RS-485s isolated, and what is total cable length?

The COM Line (RS-485 Bus) is Opto-Isolated at each Device, but that's about all!
(similar to a NIC in a Computer)

Total Bus length will be less than 200 feet.

Is Modbus a fixed baud rate? If not what rate are you using?

MODBUS Baud rates vary between 1200 BPS to 19200 BPS.
Literature for the Enercept Meters states 9600 Baud, no Parity.
I will configure the Gateway to this speed.

If high voltage was applied between the + and - signal lines and the 485 driver is destroyed, then how much else gets destroyed? If it is an isolated 485, then is it a sub module that is easily replaced? If isolated what is the isolation voltage rating?

If Line Voltage falls on the RS-485 Bus, all devices will have smoked signal inputs.

The Enercept Meters consist of (3) CTs with (4) Line Voltage input leads (for the VTs).
Serial Port, addressing DIP Switches + Software is contained on one of the Three CTs.

From where do you derive power for the unit?

Power for the Monitoring Devices (Enercept Meters) is derived from the Input Primary Voltage Leads (VT leads).

Thanks for the reply!

Scott
 
100715-1054 EST

Scott:

So if the 485 chip is fried and you want communication, then the communication CT has to be replaced. Is that correct?

Are all three input voltages used to power the device or just one?

Do you know how power is measured, and if it handles high frequency harmonics very well? What is the minimum quantizing time for power?

Do you want to collect in-rush current information?

.
 
Search for a RPM meter, fluke 1750 is a nice one. I use a dranetz, but it is not as nice as the old Fluke RPM's I have used.
 
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