Hello,
I don't have the means to measure frequency or waveform.
Excitation is AC
I am viewing the value on the HMI only. AC Voltage reading between +SG and +E is 2.4 V with or without load, same goes for -SG and -E. If measured as DC it oscillates between -5 mV and 5 mV.
AC power is connected to a main switch then a fuse and then it goes into the power supply.
The power supply is a Weidmuller CP SNT 70W 24V 3A. There is a fuse and then the EX-A1, then both IO-LC1's and then the PLC. (Daisy chained with 20AWG 600 V plastic coated copper wire).
Only AC is grounded at the main switch.
The distance between the loadcell and LC1 is less than 3 feet, the loadcells cable was not modified at all. It is a 4 wire cable, connected according to the LC1's wiring diagram for 4 cable loadcells.
The power supply does not source anything other than what has been mentioned above.
Tracking band, range and motion band were adjusted on the computer and fed to the PLC. The function is not present on the file I uploaded but they were located on the Loadcell calibration subroutine that is activated when you press the F1 key on the PLC and the HMI goes to the Loadcell calibration screen.
I am located inside an empty warehouse, there are no engines, fluorescent lights, leds or anything that could cause interference. The power lines are only feeding this system right now, everything else has been disconnected. There is a 1HP water pump connected to the system but it is currently off.
I am measuring thousandths of grams 000.000 up to 150 grams. The loadcell has been calibrated with 4 points. (0 grams, 10.6 grams, 18.9 grams and 143.9 grams) All weights were measured with lab equipment.
Their weights remain more or less stable but the rightmost digit has the variation. If I reduce the number of digits, the variation moves to whatever the rightmost digit is. I tried rounding it, but the last digit remains constant and the next digit to its left inherits the variation.
My personal guess was that the oscillation is due to the small mV variations that exist around the zero so I wanted to give the auto zero tracking function a try, but unfortunately I can't get it to work.
Please bare with me, this is my first PLC project and I have read, studied, learned and re-read almost everything there is to Unitronics regarding this subject.
Thank you.