Hey guys, just wanted to check and see if there was something I can do to tame the random values that I am getting from the SE AI 4-20 readings. Using a meter with a steady output, the reading is still jumping several hundredths (ie.. from 60.52 to 60.54 to 60.51, etc…) With a sensor attached its ridiculous. Im even using a filter to average 21 values over a period of time which helps but I still get a fluctuation of a hundredth every couple of seconds… Ive never really had this problem with Allen Bradley or even BRX, GE, other input cards. I have resolved the following. [list] [] Everything is properly grounded. [] No change when isolated or floating. [] Again, even with a measured ma signal to the thousandth, randomness on the incoming reading is still occuring. [] Happens on ALL of our PLCnext PLCs (Currently 4) [] Changing input types (Dword, UINT, DINT, REAL, Etc..) has no effect. [] We use Phoenix Contact Trio DC-UPS with a steady incoming voltage. [/list]
Hello AC, I assume you are using the I/O-Modul - AXL SE AI4 I 4-20 - 1088062. The precision of data acquisition is depends on A/D Converter and additional tolerances influenced by electromagnetic interference: Electromagnetic fields EN 61000-4-3/IEC 61000-4-3 < ±0.5% Fast transients (burst) EN 61000-4-4/IEC 61000-4-4 < ±0.5% Conducted interference EN 61000-4-6/IEC 61000-4-6 < ±0.5% I assume the values 60.52, 60.54, 60.5 are raw values, could you send me details about the used measurement setup: - Used Precision current generator with tolerances - Set current in mA Please send me the measured Raw-values (with floating tolerances) based on following table (see also attached screenshot) Input data 4 mA … 20 mA: hex dec mА 3E80 16000 +20.0 1770 6000 +10.0 03E8 1000 +5.0 0001 1 +4.001 0000 0 +4.0 … +3.2 Thanks & Best Regards Eduard
Ive used a precision generator and also ran the output from the SE AO to the SE AI and Im getting the same randomness in ALL of the PLCs I used UINT for ease of translation but no matter the conversion I use, Im getting the same randomness. hex dec mА 3E80 16000 +20.0 Reading of (15980 - 16020 UINT) 1770 6000 +10.0 (7979 - 8004) 03E8 1000 +5.0 (3973 - 4011) 0001 1 +4.001 (0 - 6) 0000 0 +4.0 … +3.2 (0-6)
Hello AC Salyers, can I contact you via email and check this behavior together via MS-Teams session? I would like to verify the raw values as showed in attachment (Set-Point: hex:03E8 dec:1000 mA:+5.0). Please connect an input channel_1 to the output channel_1 using a cable. Thanks & Best Regards Eduard
