Please see the drawing:
The portion drawn in back is existing and working. It is a load cell connected to a PLC via a strain gauge amplifier/signal conditioner. The idea is to have a display for this tension from the load cell. I plan to install the portion in red. I have been working over this plan with another technician on the other side of the world on this issue but he has become busy and unable to answer my email (or he's getting tired of my questions). He agrees with me that it would be better to install a 2nd amplifier rather than add to the output of the existing one and he agrees that it should work without connecting the exitation+ wire (to avoid the 2 amplifiers trying to supply excitation voltage) but he says that using a 3-wire amplifier will cause an offset error in the PLC or the new display or both (error proportional to cable length). He says I need to use another 4-wire amplifier like the existing one. Can anyone confirm this & explain why? I need this to work as I already have bought the display and it will only work with a 3-wire amplifier.
Thanks
The portion drawn in back is existing and working. It is a load cell connected to a PLC via a strain gauge amplifier/signal conditioner. The idea is to have a display for this tension from the load cell. I plan to install the portion in red. I have been working over this plan with another technician on the other side of the world on this issue but he has become busy and unable to answer my email (or he's getting tired of my questions). He agrees with me that it would be better to install a 2nd amplifier rather than add to the output of the existing one and he agrees that it should work without connecting the exitation+ wire (to avoid the 2 amplifiers trying to supply excitation voltage) but he says that using a 3-wire amplifier will cause an offset error in the PLC or the new display or both (error proportional to cable length). He says I need to use another 4-wire amplifier like the existing one. Can anyone confirm this & explain why? I need this to work as I already have bought the display and it will only work with a 3-wire amplifier.
Thanks