Troubleshooting bit status

[newbie2012 0]

Hi, I am new and wanted your help guys. I just would like to check the bit status of an input or output of a GE brand running petrochemical industry. One of their pump motor does not run (physical inspection) whenever they try to hit a START button from their SCADA and there is nowhere in their SCADA to check if that output bit is ON or not. My plan is to go online directly to the PLC and check the bit. I manage to know what the I/O address is by checking the I/O list. Correct me if I'm wrong to my procedures going online with the PLC: a. create a simple ladder program to turn on the OUTPUT b. set the hardware configuration on this new program (like the CPU, POWERSUPPLY, and slots - this I'm not sure if there's a need still to put all I/Os on the network on my program, or do I just put in the slot to where the bit is?) c. after validating the program, do I need to download the new program to the controller, or can I just hit RUN and check the bit? if I needed to download, do I need to upload the stored program first? BTW, its gonna be a proficy machine edition. Apologize if my questions sounds illiterate, I just need to make sure that I'm doing the right thing. Or, if there's an easy way to check the output bit status, I would appreciate for that. Thanks. :)

[RussB 22]

The easiest way is to look at the LED associated with the Output and/or measure the output with a VOM. Using Proficy ME will tell you if the logic is attempting to turn it on but that will not tell you if it works. To use PME with an existing PLC program if you do not have a backup of the program: 1. Start a new project with the same type of Target (VersaMax, 90-30 or RX3i) 2. Be sure that the configured CPU is similar to the one you are connected to. 3. Upload the hardware Configuration from the PLC 4. Upload the Logic from the PLC You may be able to do step 3 and 4 together. Now the Config and Logic should be equal and you will be able to select any I/O address and Force a bit by pressing F11 or Toggle it with F12. (If your CPU supports forcing.) Edited 17 Aug 2012 by RussB

[newbie2012 0]

Thanks for the info. I have seen the PLC rack and it appears no light. I think its time for me to go online with the PLC to check. I'll get back if I have more questions. Thanks again. :)

[newbie2012 0]

Could it possibly be a module fault? Steps tried: 1. check on the logic program, and it logically works. the coil energize when pump starts, and it also shows 1 on my table on PME. 2. checked the voltage from the power source to the module (IC694MDL740 if it makes sense), and there is a 24 VDC It appears that the module is not being triggered by the program. Any other suggestion? Thanks. :)

[Steve Bailey 118]

If the LED on the module does not light up when the program turns the output address on it could be that the PLC has lost its hardware configuration file or the file you have downloaded to it assigns the wrong address to the module.