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Everything posted by 08stevieg

  1. Hi Kaiser Will, the sensor element isn't the problem, when tested with a known source the result was 'When testing the range of the RTD in an ice bath the zero went to -4 Deg and in boiling water only reached 66 Deg c?' As you can see the resultant temperatures where not correct, I have tried different RTD's and I have the same incorrect result.
  2. I need help in identifying the fault with a 1746-NR4 RTD / resistance module. The hardware is a SLC500 1746-NR4 module inserted into slot 3 of a 10 way rack, the processer is a SLC500 5/04   I have been using the RTD module to sample the temperature of a beer-brewing kettle and a fermentation enclosure, tone of the RTD’s was used to control the cooler, the second RTD was scaled through logic and controlled a temperature element through PID logic, this has been running fine for some time. Recently I returned from work and found that the CPU had faulted, the error was on slot 3 (RTD module), unfortunately I didn’t write down the error code, but I’m sure it was xx61, I know now I should have paid more attention to this code. When I cleared the error the processer ran perfectly with no new errors, what wasn’t right was that the heater in the fermentation enclosure was switched on due to low internal temp, when I checked the temperature readings of the RTD against a fixed gauge, the RTD’s value read 10 Deg C and the gauge read 20 Deg C.   I have scaled the RTD value directly, example I:3.0 on the first line of  SCP block and I can see the temp values on this line, I believe this to be an accurate reading. I have entered the correct configuration data in the channel configuration word, i.e. the correct bit settings, I have also tried to change these, example the data format values, the RTD input type, etc.   Convinced that the module was damaged I replaced it with a spare that I had and inserted that, this has now become corrupted or damaged too, and on this one I have lost 3 channels? Example; When an RTD element is connected to the module on channel 2, 3 or 4 the green light blinks, but when viewed in RSLogix the channels indicates that there is a device connected? When testing the range of the RTD in an ice bath the zero went to -4 Deg and in boiling water only reached 66 Deg c?   I have tested both of these modules on a different PLC rack, by swapping them out with a RTD module that I know is working ok. The same fault appears with the RTD modules in either rack and with two different CPU’s. I would like to be able to confirm that the rack or pane or rack isn’t faulty. At present there is only a D/O and D/I card in the rack.   Could this is a case that the modules require re-calibration? And is this an easy fix, can these modules be reset to the factory original spec? Do they require the firmware to be updated?   I would be grateful for any assistance that could be given as I am at a loss and I think I have exhausted all avenues
  3. Hi Mikey, Thanks for your reply, I have tried your suggestion, whilst fault finding I did move the Module to the last position on the rack and re-wrote the logic, the result of the values where the as in slot 3, as I have mentioned in the post I have tried theses modules in a known functioning rack (switched off supply, removed a good RTD module and replaced it with the suspect faulty one, re-energised power and viewed the values). The modules seem to be corrupted, or I am missing something.