Monitoring of AC current

rkukl

Lifetime Supporting Member
Join Date
May 2002
Location
USA MA
Posts
194
Monitoring of AC current
Hi
I’m looking for some ideas for monitoring current of resistive heater loads. I have a new machine that has 36 heat zones controlled by a SLC 5/04 using BTM’s (barrel temperature control modules). I want to monitor the actual current of those zones real time. I have done it in a couple of ways in the past method one is to install current transformers on each zone and then set up a bridge circuit to convert the CT output to a 4-20 ma circuit. That works well but uses up a lot of rack space. Method two was to install a power monitor on the feeder to the heat load. Then by monitoring the load and doing a bit shift I was able to cycle each load in a programmed sequence with the other heats off. This works fairly well but does not allow real time monitoring of each load the reason being if I cycle thru the heat zones too often it will affect the process. So my new idea is to see if I can find any CT’s that can connect directly to a network like Device-net or Ethernet. Has anyone seen any products that might be of help?

Thanks for your ideas.

Rich
 
This may sound daft but have you thought about using a smart overload
like the ab e3? They can monitor single or three phase current and connect to devicenet directly. The e3 also provides a limited in and out capability. I know its not quite what you may be looking for, but it might work!
Any more help just ask
kevin combes
 
we have simular type of thing in our place, where we heat a barrel
through a number of heating zones.
each zone is monitor by its tempreture using a eurotherm 815, switching the indiviual zones on or off acording to the tempreture set point.
with the 815 connected to the ethernet we monitor the tempreture of that zone rather than the current in real time.

michael.
 
Thanks Jim I had not seen that brand before. I guess I'll have to use something like those connected to a SLC or remote Analog inputs.

Rich
 

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