Error logging on mitsubishi PLC

[bk306]

Hi, I am hoping to implement an error logging system on an existing automated assembly machine.

The assembly operation is sequenced by a mitsubishi PLC (FX series)

When a fault (normally a missing component) is detected the PLC stops the assembly operation and sends an error message to the HMI advising the operator of which specific error has occurred, presumably by raising the appropriate internal flags.

I have been tasked with implementing a way of logging how often each error code occurs, and ideally how long the downtime is associated with each error code.

I would really appreciate any advice you can give me on how to go about this including what software/hardware I might need and anything else that might be useful! I have some experience in PLC programming but have never worked with mitsubishi PLCs or attempted anything like this before.

Thanks for your help - please let me know if any more information is needed,

Beth

 

[Akahige]

BK306, In the FX series PLCs if an error is detected then bit M8004 is turned on and register D8004 will contain the error code. You can use these bits to record the occasions of errors on to an HMI screen. Also clock data during these errors are stored in data registers D8013-D8019. (Looking at old notes so you might need to verify this). With this information you can MOV the register information into a logging screen when triggered by M8004 for instance.

 

[Sergei Troizky]

Akahige, he needs to log the machinery operation errors, not the PLC errors.

 

[iant]

Sergei - I think with a name of Beth it might not be a 'he'

the logging you are looking for can usually be done on the HMI
it is only a matter of sending a number of alarms from the PLC to the HMI

what type of HMI are you using and does it have a CF card or USB option?

EDIT
By the way
Welcome to the site Beth.

 

[bk306]

Thanks for your help guys - at this stage any information is useful!

The HMI currently installed is the most basic GT1030-LBD option so I suspect it simply won't do what I want it to.

The HMI currently displays error messages from the machine (e.g. "waiting for component at station 5"). I assume the PLC communicates these via the coloured leads that feed into the bottom left of the HMI unit (see picture) I'm imagining one of them is an error flag and the others indicate error codes.

Has anyone got any suggestions of how I could go about logging errors and the amount of downtime associated with them from this set-up?

With my experience one option I can think of would be to hard wire an arduino board in to read off those terminals and program that to log errors, but that seems quite convoluted for what should be a simple problem!

Thanks again for your help

 

[iant]

just a couple of additional questions
- which FX series PLC
- how long do you need to keep the logged information
- how long do you need the info kept

the logging is dependent on the CPU and its available memory.
to Program for logging down time per error, you will need to assess the total amount of information to be stored.

you might be in excess of the ability of your CPU
the idea of upgrading your touch screen might be cheaper

 

[Goody]

more questions:
What software do you already have?

GX Developer?
GT Works?

I did something similar a while back With an FX2n and realised that memory was going to be an issue.
I was only logging machine 'stopped' time with 'day' and 'time of day' (The bosses suspected the operatives were stopping the machine unnecessarily)

I was limited (even after some clever routines to limit data register usage) to 50 logs per day for 5 days before the logging started from new.
( And by 50 logs I mean DAY, TIME STOPPED, TIME STARTED TIME ELAPSED, TOTAL TIME STOPPED

 

[bk306]

Ok so having finally managed to get into the PLC cabinet I now have the following information:

PLC type = FX-1N-60MR
Communicating with the HMI via the RS 422 output

I have access to GX works but frustratingly not GX developer. Having looked through the PLC program it appears that error codes are being communicated by transferring registers K0 - K21 to D852, which then prompts the HMI to display the relevant error messages.

I'm assuming the HMI reads D852 via the RS-422 cable - would this be correct?

Goody, thanks for letting me know your experience - I think I will hit the same issue if I pursue a PLC-based solution. Although the data would only need to be kept for 24 hours it's a lot of information to record (we're having >400 stoppages a day, and recording duration and cause of each of these stoppages will quickly add up!) That, and the desire for a 'real-time' display makes me think that upgrading the HMI or using a completely external monitoring system is going to be the best option.

 

[iant]

I will have GXworks soon
K - is a constant number not a register K0 = 0 K21 = 21
I think it RS485 - 4 wire

If you go for a different screen try to get both CF card and E/net.
Even look at either Proface or Redlion HMI's

 

[Goody]

In the PLC the register D852 will hold the number of the fault, the numbers K0 - K21 will be the type of fault. Any fault will MOV or MOVP the correct number into this register.
In the HMI there will be a message library that displays the fault according to what number is in D852. (or, that's usually how it's done.)