Posted 11 Jun 2015 Good day to all, Please i need your support. I am new to world of Plc. I just bought a micrologix 1500(1764-24BWA) Plc for my training program. I have a question with respect to the Input terminal 24V DC. I connected L1,L2 and the ground at the Output terminal to a 230VAC and power On the Equipment, everything was okay. My question is do I still need to connect the -DC and + DC at the Input terminal to a 24VDC external power supply to get the needed 24VDC for the Input terminal or the 24VDC comes from the internal voltage conversion of the PLC. Once again thank you for the support. Best regards Share this post Link to post Share on other sites
Posted 11 Jun 2015 The +24vdc and Com terminals are used to power your inputs. There is an internal DC power supply in the PLC. Share this post Link to post Share on other sites
Posted 11 Jun 2015 The built in power supply can be used, but it is limited to 400mA which can power a few sensors and maybe a relay or 2. If you are going to fully load the I/O an external 24VDC power supply would be recommended. Follow the link below for manuals in all the available languages: http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1764-in001_-mu-p.pdf Share this post Link to post Share on other sites
Posted 13 Jun 2015 Thank you all for taking the time to go through my post. I really appreciate your kind gesture. It seems I am still missing something out. I connected the PLC based on the explanations giving above, everything looked okay except that the indicator lamp which I wanted to control did not turn ON at all. My aim is to use a push button to ON an indicator light(24VDC/20mA). So I wrote a simple ladder program which I downloaded to the plc. Whenever I press the push button, the input- I:0/0 terminal(my push button is connected to this address) and the output- O:0/0 terminal (indicator lamp is connected to this address) indicator lights on the PLC turned ON, however my main indicator lamp did not turn ON. I do not know what I am doing wrong. CONNECTION OF THE INDICATOR LAMP TO THE PLC I connected one end of the indicator lamp to VDC0 and the other end to O/0 terminal. QUESTION If one presses a push button and the corresponding input and output terminals indicator light on the PLC turn ON but the actual load(indicator lamp in this case) does not turn ON. What does this kind of situation suggest and how can I go about the troubleshooting. Your suggestions and advice will be highly appreciated. Thank for the supports. Best regards Share this post Link to post Share on other sites
Posted 13 Jun 2015 (edited) You have to power the output terminals. One side of the lamp should be connected to Out 0 ( the plus side of the lamp) the other side of the lamp shpuld be connected to 24vdc common. The VAC/VDC 0 terminal on the PLC should be connected to the 24VDC +. See pdf below. Separate the AC power used for the PLC power and use the 24VDC power for the output terminals.powertheoutputs.pdf Edited 13 Jun 2015 by Mickey Share this post Link to post Share on other sites
Posted 13 Jun 2015 Thank you very much . I connected the terminals as you explained,everything is working now. I really appreciate your kind gesture. Best regards. Share this post Link to post Share on other sites
