Author Topic: MTU PRO spyder-only option  (Read 2129 times)

tmarks11

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MTU PRO spyder-only option
« on: January 25, 2015, 08:06:36 PM »
Why doesn't TED sell a spyder-only version of the PRO?

If I buy a SPYDER POP, it comes with 200A split core CTs to monitor power going into my panel, as well as a number of solid core CT to monitor individual load.  This is a much more useful arrangement instead of getting an MTU dedicated only to monitoring my two incoming lines.

I am willing to pay $300 to upgrade from my TED 5000 (which has three sets of MTUs) to a TED PRO spyder arrangement.  $470 is too much (cost of Pro + spyder), since it is giving me functionality I don't need.

pfletch101

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Re: MTU PRO spyder-only option
« Reply #1 on: January 25, 2015, 08:35:40 PM »
Spyder channels do not have the same accuracy specifications as the main MTUs, and they 'bottom out' (reading zero) at non-zero current flow/power flux levels which are dependent on the rating of the CT. I think that the TED folks assume that you want maximum accuracy on the main power and (where relevant) PV solar feeds but will tolerate the tradeoff between price and precision for branch feeds. Also, many people won't want the Spyder functionality.

Additional point added a few hours later: The Spyder hardware "piggybacks" on the main MTU hardware, which powers it and also does the PLC encoding and transmission of the data for it, so it is actually a pretty simple piece of kit. An MTU-less version would have to include hardware to replace these functionalities, almost certainly making it nearly as expensive to produce as the current full version.
« Last Edit: January 26, 2015, 02:47:41 AM by pfletch101 »
Peter R. Fletcher
TED Pro Home - main MTUs monitoring utility and PV Solar feeds; 2 Spyders monitoring selected individual circuits

tmarks11

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Re: MTU PRO spyder-only option
« Reply #2 on: January 31, 2015, 03:52:52 AM »
ah, good to know.  I assumed the spyder boxes were stand-alone MTU's all on their own.

I see now that the data sheet for the MTU pro discusses all this. 

Maybe the spyder is acting like a multiplexor, feeding each sensor one at a time (in rotation) to the MTU for A-D and power-line transmission.

One element of this that is disappointing is that the spyder only posts data once a minute, so you don't get to use the "seconds" graph feature with the spyder.  That is too bad, since it is useful to figure out details on your load.