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wborst

C1000h Sys(49) Instruction

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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.

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It is quite possible that it has been used for a password to protect the progam. Can you read the program in the PLC? By the way, only the first parameter is relevant, parameters 2 & 3 are irrelevant. The function was not highly publicised and was kept pretty secret. Here is a link to a manual where there is some information on function SYS(49) http://forums.mrplc.com/index.php?autocom=downloads&showfile=505 Have a look in Appendix B. I had more information on the function years ago but do not have it now. Edited by BobB

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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

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If the Hostlink is plugged into the PLC upon power up make sure the interface hostllink is set to go into run mode. Otherwise the PLC will default to Stop/Program mode. The setting is on the dip switches of the host link unit.

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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.

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

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Glad it turned out to be simple in the enad as replacing the power supply. You originally did say the the power supply led was on then through investigation it turned off....very strange. Do you think that it just died or a possibility of a power surge / lightning strike near by ?

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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

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