Often time we run into MDR issues that leaves us wondering if it's caused by the MDR card or the BnR module. This article demonstrates a simple yet effective approach to determine if either the MDR card or the B&R module is faulty. This method will help you troubleshoot better when site reports a problem about a single MDR zone (or possibly multiple MDR zones).

Typically, the follow of communications for MDRs is as follows:

Controller (ICW/BOSS/MC4) ====Ethernet/Profibus===> MDR Slave ===X2X===> BnR ===9-Pole connector===> MDR Card (CS1001 or Itoh Denki) ===10-Pole Connector ===> MDR Roller

In case one MDR zone isn't running when forced, there are few things to suspect: (This only applies if a single zone not running)

- Faulty MDR roller

- Faulty MDR card

- Faulty BnR module or No Power to BnR (The LED status on the module are good indicators, use the manual to find out their meanings)

- Loose X2X connection/Low Power. This is especially true when the zone you are troubleshooting is at the end of the X2X network.

NOTE: in a very rare occasions the MDR Slave could cause few zones to fault out. But usually the effect if far more dramatic when the MDR Slave is faulty, It would cause all MDR zones to stop.

This is what you need to do to determine if the roller, MDR card, or the BnR module causing the problem:

- First, determine if the MDR zone upstream or downstream of the troubled zone is working. You can force the MDR and ask site to confirm. Make sure to unforce when done.

- Swap CN2 Connectors between the MDR cards. Manually unplug CN2 connector from the MDR card of the faulty zone, and connect it to the MDR card of the working zone. Do the same with the working zone. The CN2 cable comes from BnR module, and it carries the Run/Stop signal from the controller.

- Now that we swapped the cables, and we know for certain that the BnR is working for the zone we tested earlier, we can force the MDR for the zone we checked earlier it was working (now connected to the faulty zone), and monitor to see if the MDR runs. If yes, then the original BnR for this zone is faulty (could be various things, but we know the problem is stemming for the BnR module now). If No, it could be either the MDR card, or the MDR roller. Suggest replacing/swapping the MDR cards and test, if not, then most likely the roller is bad.

- Optional: Force the MDR for the faulty zone (now connected to the working zone that we tested earlier). See if the MDR runs. This is just to confirm if the BnR for the faulty zone is working.

Make sure to keep track of the cables being swapped during this process.

References/Resources:

X67_B&R.pdf

MDR Control Card Quick Reference Guide.pdf

MDR 710 Installation and Maintenance Manual.pdf

Itoh HB-508S (rev_05-0816).pdf

HB-510_eng_563.pdf

HB-510-rev20-0130.pdf

CS1001 MDR Manual.pdf