1756-DNB Random Restarting

[automatt 0]

Hi, I have a 1756-DNB in a Controllogix rack. Everything has been running fine until yesterday, when the unit would restart randomly, sometimes seconds apart sometimes minutes. The "CommandRegister.Reset" bit is currently forced off for elimination purposes. The card is a master to 45 off Lenze Motec drives. I am using Explicit Messaging to obtain data from the drives such as Motor Current, Run hours, Fault Code etc. This part of the program is a periodic task and if I disable this task the random restarts cease to happen. Can problomatic or too many MSG's instructions cause the 1756-DNB to restart? If not, what else can cause it to restart? Thanks. Matt

[Eddie Willers 2]

If the system was running fine, what changed in the installation or program at the time the problems started ? For best performance, you should limit the number of simultaneous explicit messages being routed through a 1756-DNB to five. Are any of the explicit messages resulting in errors ? Are any of them not working as expected (i.e. might they be getting sent to the DNB itself instead of a node on the DeviceNet) ? What firmware revision is the 1756-DNB ? If you have access to any DeviceNet metering or diagnostic devices, the network utilization and CAN error rates would be useful information. I think I recall, in the distant past, a DeviceNet scanner performing a reboot when a particular malformed response was returned from a slave device explicit message. Can you tell us anything about the Lenze parameter read performance or mechanism (i.e. is it using Class 0x0F for the Parameters or a vendor-specific Class ?)

[automatt 0]

Eddie thanks for the reply. The firmware of the 1756-DNB is 6.1. Nothing has been added or changed software or hardware. Unforunatley i do not have access to any diagnostic equipment. There are five messages each dealing with 9 drives each. The path and instance are updated dynamically. The lenze cards (which are part no. E82ZAFC) use manufacturer-specific class 6E hex. The message type is Get Attribute Single. The whole system is divided into 9 safety zones so on occasions the MSG will return an error because the E82ZAFC card is unable to otain the data from the inverter. I'm a bit dubious of the E82ZAFC card's as we have had two fail (constantly causing bus off). Days before the first one failed, the data obtained via explicit messaging which is displayed on an HMI was very slow to update (several seconds). After the failed card was replaced, there was no apparent delay. Hope that makes sense!