Sp unit error - q3acpu

Hello from the UK!

I've been tasked with extending the Inputs on an ageing machine which has the Mitsubishi Q3ACPU, 4 x 64 (AX82) Input modules, x2 Encoder card modules (AD61) and x5 (AY13E) Output modules and 1 METSECNET (AJ71AT21B) special module.

The Last module (AJ71AT21B) isn't used but is set in the parameters.

I found (by my amazement) a SPARE input card AX82. I installed the card, and in Parameters in GX Developer the slot (0-4) and bit number (64).

As the METSECNET card isn't being used I removed this from the parameters and the hardware from the rack.

HOWEVER, although (through GX Developer) the CPU was detecting the newly installed input card (I was using Batch monitor) I noticed an error message on the CPU display:

"SP UNIT ERROR"

And had developed some strange occurrences probably as a direct result of this error.

My question is this (Yep... I finally got there!) did I miss anything in the configuration setup?

I thought as long as you went into Parameter, selected the appropriate slot, the type of module (input) and the bits (64) you should be ready to download to the PLC.

When I loaded the old Parameter setup back into the PLC (and put the comms card back in the rack) the message cleared and the machine ran.

(Of course, I can't get too much downtime on this machine as it's always in production!)

As you may have guessed I'm not too familiar with the old Mitsubishi stuff, but I am learning!

Any help or ideas will be greatfully received

Kind regards,

Karl

I am not sure whether this is your problem but GX Developer has never supported Melsecnet B networks which is what your AT21B card uses. We used to have to use Medoc to download the network parameters for these systems and then use GX Developer to download the programme. In any case there must be some network parameters set up and you will need to delete/remove these as well as changing the IO allocation.

Found it...

Hello,

Thanks for the reply!

I had another look through the code and would you believe I found a chunk of FROM and TO references to the comms card "hidden" in plain sight deep within a Sub-routine! Due to the efforts of the original programmer I expected all the sub calls to be set at the beginning of the code, but I think somebody else had been in there modifying sometime ago - No comments and "spaghetti" style of coding hashed in with no real thought. I recognise the pattern displayed elsewhere on other machines.

Interesting about using MEDOC to download the Network parameters...

Anyway, until next time

Kind regards,

Karl