H0-ECOM100 stops showing busy

[WRT]

Second time this has happened in this installation.  The ECOM100 card stops setting the busy flag.  When you send a new RX you get data from a previous RX so the result is quite serious -- bad data is being recorded without warning.
165 / 269 version, no Iboxes, all Modbus comms, nothing shows as unusual on the HCOM system memory.  Just the busy flag doesn't set.

Last time it reset after I stopped the PLC for a few hours.  I don't want to do that right now because I need to catch the bug in the act.  It may be a week before it happens again.

Thanks, Bill

[Greg]

I’m assuming from "Version 165 / 269" that you have an H0-ECOM100? I would like to see the program that does this. There are ways to mess things up if you are using RX/WXs, for example, in a stage and don't keep the stage enabled long enough for the RX/WX to complete... and other things.

But also, I'll make you aware that on very rare occasions it is possible that if you are using a DL06 and the ECOM100 takes longer than 3 seconds to complete an RX/WX that the DL06 firmware will timeout across the backplane. When this happens the DL06 actually tells the ECOM100 "you are no longer busy" (even though he still is!). The way the DL06 does this is by resetting the SP-Busy bit himself instead of waiting on the ECOM100. This action resets critical pointers in the ECOM100's memory and could potentially cause it to lock up (but sometimes it recovers). Only the DL06 does this and it is clearly a firmware bug. I have made Koyo aware of this issue and they will fix it in a future release of DL06 firmware.

If this DL06 3-second shutoff is what you are experiencing then there is a workaround:

• Make sure the product of "ACK Timeout" and ("Retries" +1) does not exceed 3000 ms.
• Make sure the product of "Response Timeout" and ("Retries" +1) does not exceed 3000 ms.

This will keep the retries of the H0-ECOM100 under the 3-second limit and thus he can maintain control of the SP-Busy and SP-Error bits without the DL06 clearing them himself.

If you are not experiencing this DL06 3-second shutoff, then, as I mentioned above, I’d like to see your program. You can e-mail it to me at support@hosteng.com.