.One software for your automation system.True Integrated Development Environment.Configure using FDT/DTM.One software tool for inverters & servos.PC-based support software for easy set-up and monitoring.Intuitive and easy to use programming tools.Powerful Machine Visualisation.Simple but effective connectivity.Omron’s devices meet ‘Open Integration’.High Performance and full connectivity.Bringing the NS to your PC.High Performance and full connectivity.Movicon SCADA Software.
Programmable Logic Controllers, along with easy-to-use Support Software, are available to flexibly handle applications from small-scale equipment to entire production lines with Programmable Logic Controllers such as those in the CJ1, CS1 and other series. One software tool for inverters & servos. CX-Thermo PC-based support software for easy set-up and monitoring. Trajexia Studio Intuitive and easy to use programming tools. CX-Supervisor Powerful Machine Visualisation. CX-Server LITE Simple but effective connectivity. CX-Server OPC Omron’s devices meet ‘Open Integration’ CX-Compolet/SYSMAC.
The Omron C20K, C28K, C40K and C60K shoebox programmable logic controllers have been discontinued since March of 2002. These ‘K’ series PLCs were a popular controller and have been in installations for over 25 years. We will take a look at this PLC and review some troubleshooting techniques. Planning for the eventual fatal failure of the CPU will also be discussed.Find parts for your.The following are the manuals for the ‘K’ series PLCs. You will note that the C20 manual is also listed.
This is because the ‘K’ series could use the C20 expansion modules. The C20 was also referred to as a ‘Flatpack’ PLC.Operation Manual – Sysmac C20K/C28K/C40K/C60K Programmable ControllersThis manual will go through the instruction set as well as how to program the unit using the handheld unit. (3G2C7-PRO15-E)Installation Guide – Sysmac C20K/C28K/C40K/C60K Programmable ControllersThis manual will review the installation and troubleshooting techniques on this programmable controller.C20 Programmable Controller – Sysmac C-Series – User’s ManualThis manual includes the installation, instruction set and troubleshooting of the C20 PLC.HardwareThe K series PLC has very rugged hardware. Power supplies on this unit are rated for twenty five years before failure.
This is why we are discussing the unit and plans for upgrades.The above picture will show the components on the CPU base of each of the controllers. It’s important to pay attention to the indicators on the front of the unit. This will tell us the condition of the PLC.DIP switches will control items such as language and program transfer from EPROM to RAM. Check your EPROM sockets to see if a chip has been placed in the unit. If so then your program is still intact.Errors on the CPUThere are two possible error types in the PLC. Fatal and Non-Fatal.Fatal errors will happen when the program, or parts of the program have been lost. They can also happen if there is a power failure.
(Fuses) The program will not run during a fatal error.Non-Fatal error will still run your program. There will be a blinking error light to indicate the error. Typically this error is due to a battery error.
(Battery needs to be replaced.)To access the components in the main unit of the PLC, remove the 4 screws on each corner of the PLC.Note: When removing the screws and working in the unit, the capacitor that keeps the ram memory stored is good for 5 minutes. You should always start by having the power onto the unit to charge the unit. While charging unscrew the 4 corner screws. Turn power off, and remove the top unit.Fuse ChangeThere are two fuses in the PLC.
One for the incoming supply and one for the 24VDC power supply. They are in fuse holders and designed to be replaced when needed.Battery ChangeThe is in a holder and has a connector that will plug in. You will have only 5 minutes to change this battery before you will lose the memory in the unit.Relay Changeon these controllers used sockets. This way the individual relays could be changed without replacing the entire unit.Note: A relay puller was also included inside the unit to the right hand side. This allows you to change the relay without bending the pins.AddressingThe K series PLCs used a fixed address system. A maximum of 10 16-bit registers could be used for each CPU unit for the expansion I/O units added.Example:C28K-CDR-A (CPU 16 DC inputs / 12 relay outputs) + C20P-EDR-A (Expansion 12 DC inputs / 8 relay outputs)Channel 0 – Address 000.00 to 000.15 – 16 DC inputs CPUChannel 1 – Address 001.00 to 001.11 – 12 Relay outputs CPUChannel 2 – Address 002.00 to 002.11 – 12 DC inputs ExpansionChannel 3 – Address 003.00 to 003.07 – 8 Relay outputs ExpansionHandheld Unit3G2C7-PRO15-E was the handheld unit that attaches to the peripheral connector on the CPU unit. This was one of the most popular methods to program the controller.
A selector switch on the unit allowed you to select between Run, Monitor and Program. To view any alarms on the controller, plug the handheld unit into the CPU.
Ensure that the switch is in either Run or Monitor mode. (This will ensure that the CPU continues running if we have a non-fatal error.) Press CLR, MON, CLR. Your unit will display the error in the CPU.You can see the entire operation of the handheld in the operation manual listed above. I also demonstrate the use of this handheld in the video below.You can still get these units off of ebay or other locations:SoftwareUsing a (Host Link) unit which plugs into the peripheral connector you can communicate to a computer. The software that originally came out to communicate this way was This was DOS based and programs saved with this software used the extension.DAT.
When windows came out you could use the Omron programming package called. Currently both of these packages are obsolete. The latest package is called CX-Programmer which is part of the CX-One software package. CX-Programmer will not program the K series or C20 PLCs.
It does however include a CX-Programmer File Converter. This converter will convert your old programs done in LSS or Syswin to a newer format. You can then change your addressing to suit this new controller.FutureYour Omron K series or C20 CPU will fail. To ensure that you do not loose your logic for a machine, I would verify that you have a copy of the program. This copy can be the list of mnemonic codes, written down from the handheld unit or a program in LSS that has been converted to CX-programmer.
Ensure you take steps so the program will not be lost on a fatal error.Find parts for your.Watch on YouTube:If you have any questions or need further information please contact me.Thank you,GarryIf you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.To get this free article, subscribe to my free email newsletter. Hi Gary I have a custom system that used a sysmac C28K omron PLC controller that went into cold storage for a long time. This system needs to be setup again. I got everything cleaned up and tried powering up.
The PLC goes into an alarm right away. I took it apart and replaced the battery on it. The battery melted in place long time ago. I don’t have a backup of the program that was loaded. Do you think the program is long gone or it it stored on an EEPROM on the controller and all I have to do is clear the alarm?
Hi Garry!Thank you indeed for your dedication to everyone’s knowledge. Outstanding example on these daysI have a question about a C28K: I have one working with a old batterie and no EPROM or other backup of the program. I read on the manual you kindly pointed that the PC is able to clear an EPROM if the respective switch is ON thus this means it is possible as well to write the program on it, I mean in a “upload” command or so?
That would produce the wanted program’s backupThank you once again, Garry BIG cheers. Hi Fernando,Thank you for the comments.A Graphic Programming Console (GPC) is the device that you are talking about. I have not seen one in about 25 years.The best way to save your program is to use software on your computer. (LSS or Syswin) The computer will talk through a serial port to a host link unit that mounts on the K series CPU. The host link unit is a 3G2C7-LK201-EV1.Another way would be to use a CPU mount unit with a keypad.
Pro15 unit or something similar in the video above.Unfortunately you cannot write the program to an EPROM mounted in the CPU.Hope this helps you out.Regards,Garry. Hi,I have a C28K in control box that runs a hydraulic pump to a Muffin Monster at sewer pumping station.
As I recall there was an issued that was fixed probably 8 yrs ago with the unit we have, however I don’t recall the fix. Some strange behavior with oil temp and oil pressure warning lights and complete shut downs but our electrician couldn’t pin point problem in other electronics. I’m wondering if the fuses or battery inside the PLC was the fix before.
The PLC has the same stickers or stamps as in the original control box itself so I don’t thing the replaced the entire PLC.What type of battery does the C28K have in it and what type fuses would expect to need to replace any faulty ones.Thanks for any input.This is all new to me. Hi Doug,Here is the installation guide for the controller.Section 3 – Maintenance and Inspection is on page 45.If you have a flashing error light, this usually means that the battery needs replacing.Battery:Fuses are listed in the above manual. This would usually mean that you would not have power to your cpu or outputs.Relay units can have individual relays replaced. If an output light is on but the actual output is not switching you can replace the relay.I hope this helps you out.Regards,Garry.