Modicon Concept 984 Modbus error?

[Latzi]

Hi Gents,


I am not familiar with Concept (familiar with Modbus however) and I was asked a question from one of my customers about an error they are getting intermittently :

"984 - Not logged in or a user is logged in on another port Please return to offline mode to re-login to the PLC"

Any idea what this is or where I could do some research on this ?

I only have a screenshot of this error so I am not even sure what the software they are using is but I think hey are running Concept on a WIN 98 VM.
Thnaks

 

[Nethop]

I've never experienced this with MB+, only with TCP/IP communications.

It seems to me that the port is still "in use" from the last log in.

I haven't been able to connect until I cycle the power to the NOE (Ethernet Module), which in my mind, clears the port for a new log in.

Dan.

 

[Latzi]

So when you start the Concept s/w you need to log in ? This is what I understand. As far as I know this PC is used with a USB to Modbus Plus converter to see the PLC's on the network.

So I am assuming that when one starts the Concept software a log in is required.This PC is the only one used for this so there is no way someone else logs in and takes the "port". by the way what port that error refers to ? is there any manual I could go through ?

Thanks for your time.

 

[GeoffC]

The error occurs when you have a programming connection open to the plc and that connection gets interrupted without closing the connection, then when you try and reconnect the plc will reply with that error. I would guess your usb converter is going to sleep, or losing connection somehow

 

[Latzi]

Hi Geoff,

I guess there is not much one can do to prevent this.Specially when the connection gets interrupted without the user intervention(bad connection,issues with the USB to Modbus Plus converter,etc). Perhaps searching for an updated driver for the USB to Modbus converter would improve the connection stability.

 

[BobB]

Check to see if the USB port is enabled for sleep mode to save power. Which version of Windoze? Probably at least Vista. I turn all power saving stuff off - drives me nuts when comms drop out and you have to re-boot or something.

 

[Latzi]

Hi Bob,

I am not sure about any details. This is a question which was asked by a future customer of mine. I think the software runs on Win 98 running on a VM machine hosted on Win7. So I am not sure what the settings of the VM Ware Player are in relation to the USB port. I will check. I simply can't remember if WIN 98 had any setting regarding the USB port management ? It could simply be the case that the Win 98 machine goes to sleep which kills the connection without stopping it first.

I will check all this.