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Hi, We have a discussion in our office concerning the correct way of wiring an external current signal 4-20mA to a 1756-IF16 module. (We do many different PLC brands and configurations, so my/our experience with Alan Bradley is of several years ago) We have several external current signals connected to these units. (And these systems are all situated on a ship.) Some are galvanic separated and others are not and have their 'own' power supply only a few are sensors that are loop powered by the Main PLC cabinet. The issue: According to one colleague it is required to connect the RTN jumper wires to the negative of the main PLC cabinet to solve signal issues due to floating voltage. Although it will work, I am not sure if this is really necessary, and I don't like connecting the negative to other cabinets which have their own power supply... Alan Bradley does not indicate that this is required, only jumper wires to convert the circuit from voltage measurement to current. It is also disappointing that none of the (non-differential) examples of Alan Bradley show how to connect an external current signal (which would indicate if the extra negative to be needed) Adding galvanic separators and connecting the RTN to the negative is in my opinion not so much a solution but an evasion of the question/issue. Any knowledge out there? Thnx

View File Temperature measurement using Arduino Nano, RTD PT100 temperature sensor and 4-20 mA transmitter Temperature measurement usind Arduino Nano, RTD PT100 sensor, 4-20 mA current loop transmiter, and a python app for visualization Submitter Absolutelyautomation Submitted 04/01/2016 Category Other PLC Demo Software  

Hello everybody, I am connecting my DCS digital output (115VAC) to AB PowerFlex 753 Digital Input. We are using the 20-750-2262D-2R I/O option in the powerflex which is 115VAC I/O with 2 Analog In, 2 Analog Out, 6 Digital In and 2 Relay Outputs. My question is, what is the current or power consumption of the PowerFlex DIs at 115VAC. I need to specify the right fuse size for my digital output. Thanks,

I have project where I need to measure motor current but I do not need to control the speed of the motor since it would always be running at full speed. Do I still need to use VFD to get feedback or is there cheaper way to measure the current?