adccommunitymod (AutomationDirect) asked a question.
Created Date: October 22,2007
Created By: bartb102
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Anybody have noise trouble with the Rhino power supplies? We have installed a number of PSP24-024S supplies to power PLC's and B &B fiber optice converters. We seem to be having issues with noise interfering with communications. Latest issue, DL450 talking Modbus to other equipment over fiber optic link. Link had B &B power supply powered by 120VAC operating B &B fiber optic converter (only load). To maintain communications during power outages, replaced B &B supply with Rhino PSP24 powered by 125VDC battery source used by most equipment in hydro plant. When on Rhino supply, I get a communication error (NetRX Failed bit) every 1000 good reads or so, sometimes more often. At one point I would get 5 failed reads in a row, shutting equipment down. With B &B supply, I have gone 60,000 reads without a single error. Swapped between the two supplies a few times, Rhino always causes trouble, B &B never. In another plant Rhino supplies power to 206 PLC. Similarly, we can get enough noise on ethernet link to shut down the e-net card, requiring a PLC reboot to start it up again. PLC serial port talks Modbus to same equiment as fiber system, just hard wired, about 3ft long cable. There may be Modbus errors, program does not have same counters. Ethernet is major headache. Thanks for any help, ideas, experiences, etc.
Created Date: October 23,2007
Created by: a agnone
I have never had any problems with noise using a Rhino Power Supply. I would be interested in replies to this. Is the negative from the Rhino grounded? I never ground the negative to neutral. Only in one case did the manufacture of a servo system recommend grounding the negative from the power supply to neutral because of a noise problem with the 0-10v signal. The power supply was a Wago in that peticular case. You mentioned Modbus, do you need the terminating resistor on the line?
Created Date: October 23,2007
Created by: bartb102
We have tried both grounded and ungrounded systems. At the plant with fiber optics I have tried connecting (-) to the RS485 C terminal on the device that has one, no difference. The RS485 lines are quite short (less than 5 ft) so no terminating resistor. B&B doesn't recommend them unless you are running a long distance. 24VDC line from Rhino to fiber optic is about 15 " long.
Thanks for your input.
Created Date: October 22,2007
Created by: bartb102
Anybody have noise trouble with the Rhino power supplies?
We have installed a number of PSP24-024S supplies to power PLC's and B&B fiber optice converters. We seem to be having issues with noise interfering with communications. Latest issue, DL450 talking Modbus to other equipment over fiber optic link. Link had B&B power supply powered by 120VAC operating B&B fiber optic converter (only load). To maintain communications during power outages, replaced B&B supply with Rhino PSP24 powered by 125VDC battery source used by most equipment in hydro plant. When on Rhino supply, I get a communication error (NetRX Failed bit) every 1000 good reads or so, sometimes more often. At one point I would get 5 failed reads in a row, shutting equipment down. With B&B supply, I have gone 60,000 reads without a single error. Swapped between the two supplies a few times, Rhino always causes trouble, B&B never.
In another plant Rhino supplies power to 206 PLC. Similarly, we can get enough noise on ethernet link to shut down the e-net card, requiring a PLC reboot to start it up again. PLC serial port talks Modbus to same equiment as fiber system, just hard wired, about 3ft long cable. There may be Modbus errors, program does not have same counters. Ethernet is major headache.
Thanks for any help, ideas, experiences, etc.