Why Can't I Communicate with My FP-1000?Hardware: FieldPoint>>Controllers/Network Modules>>FP-1000
Problem: I have had several FP-1000 units that have repeatedly stopped working in the past. I have RMA'd these network modules in the past and received reports that two resistors (R44 and R45) inside the unit were fried. Why am I burning up these resistors? Solution: There may be a potential difference between the ground of the computer and the ground of the power supply connected to the FP-1000. A potential difference between the grounds can cause current to flow from the computer ground across the RS-232 cable to the FP-1000 ground. This can cause R44 and R45 to burn up as well as other components if enough current is sourced. Sometimes this sort of ground loop can even cause burn marks on the RS-232 cable. To determine if this is the problem you are having, disconnect the RS-232 cable from the FP-1000 and leave it connected to your computer. Use a DMM to measure the voltage between the shield on the cable and the shield on the FP-1000 RS-232 connector. If you measure more than a few millivolts, you've found the problem and can fix it by ensuring that the computer and all power supplies in the system are connected to the same ground. Related Links: FP-1000/1001 User Manual Attachments:
Report Date: 07/21/2004 Last Updated: 05/12/2005 Document ID: 3BKA86GR |
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