AC Current Sensing Using PLC

Hi there, I am new to this forum and a guy in need.

My current project involves temperature and AC current sensing while temperature is to be displayed on 7 segment displays. 3 displays will be used (temperature resolution of 1 deg is more than enough). Plus, a valve is to be operated proportional to load demand (current drawn by the load). And all of this is being done from a PLC, most probably it would be a very basic one from Fatek having 2 analog inputs, one analog output, 8 digital inputs and 8 digital outputs.

I dont have any thermocouple, 7 segment or AC current sensing add on modules for PLC.

For temperature sensing, I am using a Temperature Transmitter for thermocouples.

I need help for making the display panel and AC current sensing. Is using 3 multiplexed BCD-to-7 Segment Decoder a good idea? (That ll require 7 DO's)

Secondly, I need help for AC current sensing. Sensor is a current transformer. Current range is 1-5 A ac. I need a scheme that converts this current in to a 4-20 mA signal that can plugged in to the Analog input.

Thank you..

I would recommend Red Lion AC current display with analog out put options. They are fairly priced and very reliable.

There are a multitude of other brands of devices with 7 segment displays that can convert a CT signal to a DC analog as well as display the value. I would buy a device that does the display and signal conditioning, and let the little PLC alone to do it's control thing, rather than display logic.

http://www.redlion.net/Products/DigitalandAnalog/DigitalPanelMeters/ACCurrent.html

I think most of these may require the separate purchase of the CT.

Weidmuller and Schenider, amogng others, produce converters 0-1/5/10AAAC to 0(4)-20mA.


http://www.schneider-electric.com/corporate/en/products-services/automation-control/products-offer/range-presentation.page?p_tab_type=products&p_range_id=611&p_url=http://www.ops-ecat.schneider-electric.com/ecatalogue/browse.do%3fel_typ=product%26cat_id=BU_AUT_611_L3%26prd_id=RMCA61BD

(Clink links for Automation Direct examples.)
First, look at a Temperature Controller. Input is a Current Transformer with 0-10V output. Controller has universal analog output. Probably not enough I/O for your project.

I'm confused about your inputs. I assume one AC current, and 3 T/C's. How will operator input the setpoint? A touchscreen is best.
The Analog Click has similar specs to the Fatek, but it's not enough for multiple T/C's.

Use a DL06, 4 channel T/C module, 4 channel Analog Output module, and small LCD touchscreen. Use type K thermocouples.
If you prefer a TFT touchscreen, look at this one.

CR Magnetics makes a current sensor that creates dc signal (0-5V or 4-20mA)proportional to AC current.

I prefer the split core style:
http://www.crmagnetics.com/products/CR-41101120S--P16.aspx


http://www.crmagnetics.com/products/CR9521-P157.aspx