rslogix 5000 and current measuring

[stu]

hi, can anyone help,i have 6 x 3phase (415v) heater circuits which i would like to view the current on each phase to see if any heaters are faulty ,hasany one done this with rslogix 5000 if so how? thanks stu

 

[leitmotif]

Stu
About a month ago there was a long post on this idea. looked at from almost any perspective you wish.

couple questions
do you just want to do each of 3 phases feeding teh six heaters
OR
do you want to monitor each heater

What will you gain by this as opposed to
-- daily or weekly clamp on readings
-- panel mount ammeter with select switch for each phase?

How will you distinguish between an open heater as opposed to one that is turned off?

Do you intend to have any control or is this strictly to monitor?

You can monitor current with either current transformers or hall effect current sensors either one can be obtained with either 4 to 20 ma or 0 to 50 mV. Allow 25 to 50 US $$ for each sensor - wont be a cheap project for all 18 heaters.

Dan Bentler

 

[Roy Matson]

I have used http://www.greystoneenergy.com/English/products/power/products_power_switch.html
With one transducer, measure one phase and assume the other Phases are equal. KW = LV x LA x 1.732
Most heating applications I have seen use the time duration method of power control, i,e a variable time ON for each fixed period (e.g. 3.00 seconds ON for a 6.00 second period would equal 50% power) so if you know the heater size you just use the ON time to calculate the power input without using a current transducer (checking with a clip-on if you suspect an element fault)

Regards
Roy

 

[The Plc Kid]

I use these. They work very well. You can get them in various current ranges and 0-10 or 4-20ma outputs.