wborst

I have also done this in a pinch. But as pointed out previously, it is truly a PITA to troubleshoot. I think I was using an Omron photosensor.

How about using a small dedicated PLC for detecting the missing label. For example, use a through-beam or retroreflective photosensor to detect the labels. Use a timed interupt set to interupt every 2 or three milliseconds. at each interupt, do and immediate input of the 4 photosensor signals. If any input is not detecting a label, Increment a counter. If any counter every reaches 2, that indicates that a space between labels that is greater than the normal gap. Use this to set an output that is connected to the main control system. I believe that a Dl06 from Automation Director a Micrologix from AB is capable of the required speed. Just a thought.

I use a Samsonite Wheeled computer bag. It has plenty of room for all the cables for connecting to various brands of PLC's as well as a few small tools. And there is even room for some documentation folders and my PC. Once I have all that stuff loaded into the bag, I'm very glad that it has those wheels and a retractable handle. I have used this setup for several years and have been very pleased with it.

If you want to purchase some of these components, a good souce for used, refurbished Omron products is www.plccenter.com . I purchase a CPU and power supply for a C1000H system just last week. They have quite a good inventory and their refurbished items come with a one year warranty. They do ship worldwide. Hope this helps.

As indicated in my post of March 28th, the power LED was on as long as the expansion rack cable was connected. I can only guess that the expansion rack power supply was somehow causing the CPU power LED to illuminate. When I disconnected this cable, the CPU power LED went out. This is what caused me to suspect the Main rack power supply. (The main rack power supply does not have a power-on indicator. Only the one on the CPU). Anyway, it taught me to not believe the CPU power indicator unless the main rack is disconnected from any expansion racks. Thanks again for your input and interest. Bill Borst Alamance Control Services

The Power Supply fixed the problem. Thanks for the assistance.

I checked the switch settings for this possibility. They were OK. I replaced the CPU but the problem remained. I don't know if I mentioned this, but this system has a main rack and an expansion rack. Yesterday, after trying a new CPU, I disconnected the cable linking the main rack with the expansion rack just to isolate the problem. To my surprize, the CPU power light was no longer on. The fuse in the power supply checked good and power was present at the 120VAC terminals. I had assumed that the power supply was OK since the power light on the CPU was on. Furthermore, the 24VDC aux power from the main rack power supply was not operating. I also noticed some discoloration near the top of he power supply. Given these indications, I have order a replacement power supply for the main rack. If anyone knows of any other things I should be looking at, please let me know. I can use all the help I can get.

Thanks for the reply, BobB. I have not been able to get connected to the PLC through the host link. I believe that the CPU is not functioning. I have ordered a replacement CPU that I will install next week. The machine was running about 6 months ago but has been sitting idle with power applied since then. When the plant personnel went to start up the machine this week, the PLC would not go into run mode. I was called in to help them troubleshoot the problem. Although I have quite a bit of expereince with other Omron PLC's, I have never worked with the C1000H. I verified that proper power is comming to the PLC. Personally, I have never seen a CPU not go into run mode without some type of alarm or error indication. The only indicator light that is on is the CPU and Power supply Power lights. Of course the input module indicators are lit up but no outputs are on. There is also a Cam Positioner module installed in the rack. It seems to be functioning properly with no alarms indicated. Since the CPU just seems to be totally unresponsive, I suspect it has failed. Any thoughts you may have, given this further information, would be greatly appreciated. Best Regards, Bill Borst

Hi All! I am working on a problem with a C1000H PLC system. The CPU will not go into RUN mode but there are no error or alarm indicators on. I loaded the program from diskette (LSS format) into SYSWIN just to take a look. There is a SYS(49) instruction being used. Syswin indicates that operand 2 is out of range. It is presently set to 9. The description of just what this instruction does that SYSWIN provides leaves a lot still in question. I also can not find any rference to this instruction in the C1000H Operations manual that I downloaded from Omron's library. Can any of you smart Omron guys explain to me just what this instruction does? In this program, it is executed on every scan. Operands 1 thru 3 are #0002, 9, and 70 respectively. Thanks for any help you can give me.

The most accurate method for determining the time for one revolution of the rotor is to use the SCAN(18) instruction to fix the PLC scan time to a known time that is slightly greater than the maximum scan time of the PLC program. Once this is known, simply increment a DM on each scan until the rotor prox input goes true. At this transition, move the data to another DM for use in computations then move zeroes into the previous DM. Now multiply the count that you just saved by the number of milliseconds per scan to give the number of milliseconds per rotor revolution. Divide 60,000 by the number of milliseconds that occurred during the one rotor revolution. This will give you the cycles-per-minute for the rotor.

Just thought you guys might want to know that I am the guy who wrote the original program for this machine. The problem that caused the most trouble in doing this is the fact that the table and range compare instuctions insist that the first paramater be smaller that the second. This makes it a bit tricky if you want to setup a window that starts at say 300 degrees and ends at say 20 degrees. This took a while to figure out. Basically, when the data for the ON and OFF points of the electronic cam portion of the program are entered via the NT20 display, they are checked to see if the ON value is larger than the OFF value. If this is the case, the value is are traded and a bit is set in a register that indicates that the output of the compare function must be inverted. You did a great job of deciphering my code. The comments I'm sure helped. Have a GREAT day! wborst

I looked at your program and it appears that you have not set the inputs 0.02 and 0.03 for interrupts. They are set for normal input. You need to click on the SETTINGS folder on the left side of the screen, then select the Inerrupts tab. On the left side of this window, you can set the function of bits 0.03 through 0.06. Try this and see if this works better. By the way, the Omrom CPM2A manual states that interupts are available for count-up on this PLC.