adccommunitymod (AutomationDirect) asked a question.
Created Date: December 07,2012
Created By: dangercraft
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Hello everyone, I just got my Click PLC C0-02DR-D... while I have a fair amount of experience with MCUs and general electronics this thing has me perplexed... I installed all of the software and I am able to see the plc ok. I have a data view open and when I apply 24v+ from the power supply to my inputs from the attached power supply all of the proper blinkenlights on the plc shine and the proper bit variable changes state. So far so good... Now, I assign 4-20 to the first of my analog input. Now I have an indicator that is connected to 4 load cells and has a 4-20ma output beside the LED digits and RS-232 connection. As far as I can tell: I connect 24v+ from the power supply to pin "load input " on the indicator,(its a chinese manual) then I connect pin "ground "on the indicator to the analog input pin on the Click. Then I connect the analog common on the click to the ground on the power supply to complete the loop. For the life of me I can't tell why its not working. I get no changes in the variables when I change the weight on the load cells even though the indicator is showing the weight in the LED digits. As far as I can tell, the indicator is doing its job since I can see a voltage change by measuring with my multimeter with a 250 ohm resistor in series to make a voltage divider. Any ideas on what I might be doing wrong? Thanks! Frank
Created Date: December 07,2012
Created by: plcnut
I have not used a click, nor am I looking at the manual to know for sure, but it sounds like the polarity may be reversed on the Plc end of the loop.
Created Date: December 07,2012
Created by: bcarlton
It sounds like the unit is a two wire device? But from your description it sounds like a current sinking device and you would need a current sourcing device.
Can you provide any diagrams including how you are testing using the 250 ohm resistor?
Created Date: December 07,2012
Created by: dangercraft
Hey PLC, Bernie, thats very much for replying. :)
Well, I guess you get what you pay for... and I'm not so dumb after all.
I decided to pull the indicator apart to see if there was any loose connections to the db9 port where the two pins brought out from the box and it turns out the manufacturer didn't connect the any of the pins in the DB9 to... well, there is also no J602 jumper on the PCB where its supposed to go (according to the manual):(. Oh well, I guess that serves me right for buying cheap junk. :D I would call the vendor but I have a feeling thats gonna get me no-where.
Oh well.
Frank
Created Date: December 07,2012
Created by: dangercraft
Hello everyone,
I just got my Click PLC C0-02DR-D... while I have a fair amount of experience with MCUs and general electronics this thing has me perplexed...
I installed all of the software and I am able to see the plc ok. I have a data view open and when I apply 24v+ from the power supply to my inputs from the attached power supply all of the proper blinkenlights on the plc shine and the proper bit variable changes state. So far so good...
Now, I assign 4-20 to the first of my analog input. Now I have an indicator that is connected to 4 load cells and has a 4-20ma output beside the LED digits and RS-232 connection. As far as I can tell: I connect 24v+ from the power supply to pin "load input " on the indicator,(its a chinese manual) then I connect pin "ground "on the indicator to the analog input pin on the Click. Then I connect the analog common on the click to the ground on the power supply to complete the loop.
For the life of me I can't tell why its not working. I get no changes in the variables when I change the weight on the load cells even though the indicator is showing the weight in the LED digits. As far as I can tell, the indicator is doing its job since I can see a voltage change by measuring with my multimeter with a 250 ohm resistor in series to make a voltage divider. Any ideas on what I might be doing wrong?
Thanks!
Frank