EX-RC1 Stopped working (only BOOT mode available)

[Rick_PN]

Hi,
me again, having problems with Unitronics hardware. This time with module EX-RC1.

After 3 months of operation the EX-RC1 module stopped working. CANbus network ceased to work so I had a look at RC1. Only the power LED was lit but I couldn't connect to the module via serial (I tried all bound rates) or canbus. I decided to unplug the module and test it in the "lab".

So I connected it to 24 VDC and to serial connection via provided  RS232 adapter. Only the power LED is lit and the module is not responding to any "request" via "Communication - PC setting" window in VisiLogic (latest stable version).

Then I decided to move all dip-switches (unit ID) to OFF. It made no difference. Then I moved all dip switches to ON -> LEDs for I/O COMM. and Bus COMM started to blink (PWR LED was ON too). After that I was able to establish connection with RC1.
I ran "Get OPLC Information " and response is: EX-RC1-BOOT A 2.00 (20). So I suppose this is not "regular" mode?  Then I ran PLC Status Get command, response was "Stop, Idle, Idle, Ready, No Error" (unit is in stop mode, flash and memory are idle). I tried to Install operating system (OS V5.04) and all looks like it did the job - status bar for installation was progressing and no error was thrown.

But it seems I cannot instruct the module to switch to OS (Run mode), all buttons are grayed out - pic bellow:

If I turn module off and on again - there is only  PWR LED on and no response from the module (we are back at the start).  Its like it can't go to RUN mode. It seems I can't download any program in this "BOOT" mode or factory reset the unit? If I try to download the program I am getting error "Retry binary transmit 1-3 (error0)". 

 

How to solve this issue?

[Ausman]

Hi Rick,

Did you check the cable before removing things? Including the resistors?

Did you do an Initialise and Reset on everything before removal and playing?

It does sound like some sort of corruption, but simple things should be tried before jumping in the deep end!

cheers, Aus

[Joe Tauser]

Downloading the OS is the proper thing to try.  If that didn't work there's something wrong with the RC1.

Joe T.

[Rick_PN]

I did check - canbus, serial, supply voltage. I turned it on and off. Then I disconnected it from canbus and  try to connect only with serial - no luck (only PWR led was lit). After that I had no better ideas.

In the lab I moved all dip switches to ON and I was able to connect via serial (it displays EX-RC1-BOOT). I did try all of those commands Run/Reset/Stop/Initialize&Reset and there is no difference. I downloaded the OS and it seems like this procedure completes with no interruptions (mind that at this point RC1 is still in BOOT). Then I power it off-on or send "Reset" command  and after that I  still can't connect via serial (PWR led is on others are off). Seems like RC1 can't load OS and go to Run mode. 

[Ausman]

As Joe says, there's likely something wrong with it.  Whilst organising a replace, is there anything hugely inductive in it's cabinet that might be affecting it?  Or inducing stuff into the canbus line along it's route?  Big vibrations? It is unusual that it has failed after 3 months. 

cheers, Aus

[Rick_PN]

No nothing special around it. Just a 10A 24VDC PSU 20cm  bellow, two 8 DI and 8 DO units and a hydraulic electric valves, about 70cm away.

Canbus cable is in its own PVC 30m long tube, there is about 10cm spacing from the other, power line PVC tube which caries 3phase 20A. Temperature of the installation never goes bellow 10°C. There are no noticeable vibrations.

[Ausman]

 Are the electric valves clamped (diodes...not bolts!) well enough?  Or don't need it?

cheers, Aus

 

[Rick_PN]

I think so, valves have connectors, supplied by manufacturer with inbuilt shunt diodes.

There are some news:  today I turned on the RC1 unit (by supplying 24 VDC). It was the same situation - PWR led on, no communication possible.  Then I left the unit for 10 minutes and when I came back PWR led was on and I/O COMM. led was blinking. Connection was working too. So I ran  Get OPLC Information, response: "EX RC1 A 5.04 (14)".  After that I run PLC Status GET and it was in Stop mode. Then I executed Run  command and the I/O COMM led turned off, but the Bus COMM. led started blinking.  Unit reported that it's in Run mode:

 

What's best to do now to diagnose the problem or somehow to reset it to factory default? 

 

[Ausman]

That sounds suspiciously like a dud solder junction, or some other bit of the electronics on the pcb, being affected by thermal change.  Someone else may have other ideas, but for me it would be a return to Unitronics with a warranty replacement, and get your supplier on board to do it "extra pronto".  In theory they always like to have failed units to check what went wrong.

I know this may not get your device running again as quickly as you want, but perhaps the lesson here is to have a spare on hand anyway?  They're not that expensive. I keep one each of spare units on hand for what I work with.  And Murphy's law must be the reason I've never needed them.  I've perhaps been lucky, never having an issue with anything, and some of this is many years old. 

cheers, Aus