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| 7/30/2020 8:42 AM | |
Joined: 5/16/2018 Last visit: 4/28/2024 Posts: 8 Rating:
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Dear All, I am using ET200SP AI Module (AI 8XI 2-/4-Wire Basic 6ES7134-6GF00-0AA1). I have VFD speed reference feedback signal (4 to 20 mA & 2 wire). I am connecting this two wires directly to I0+ (Terminal-1) & Uv ( Terminal-9). I am measuring the current 4.0 mA in the multi meter. But in Online that channel is giving 32767 counts. When i am injecting 4-20mA from the source meter, PLC channel is reading the correct counts based on injected current. I cannot able to predict the problem is from VFD side or PLC side. When i am connecting the sensor cable (I+) to PLC I0+(Termianl-1) and sensor (I-) to SMPS-24VDC ground in the PLC panel, without any issues, i am reading the accurate VFD speed. Kindly suggest me, is that correct way to connect two wire sensor or any other problem will be there in the future. ------------------------------------------------------------------------------------------ |
Last edited by: vikram.mani at: 07/30/2020 08:47:08Last edited by: Jen_Moderator at: 07/30/2020 11:35:08New subject after splitting |
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| 7/30/2020 3:03 PM | |
Joined: 3/5/2014 Last visit: 8/5/2022 Posts: 5521 Rating:
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hi, the difference between 2-Wire and 4-wire-transducers is that the 2-wire-transducers have their power supply through the measurement-wires. Thats the reason why only 4..20mA-range can be used with it. 4-wire-transducers have 2 wires for measurement and the other two wires are the power-supply. SIMATIC S7-1500, ET 200MP, ET 200SP, ET 200AL, ET 200pro, ET 200eco PN Analog value processingIf I understood it right, you should have a 4-wire-sensor. Therefore you need a 4-wire-module. I meant a wiring diagram of your sensor, not of the Siemens-module. I know them very well ;) hope this helps, regards, |
Last edited by: mopS04 at: 07/30/2020 15:09:13FCK WAR! |
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| 7/31/2020 4:23 AM | |
Joined: 3/28/2010 Last visit: 1/13/2025 Posts: 1102 Rating:
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Your 4-20mA output signal (+) needs to be connected to In+ (n is an available numbered input) and the output signal (-) needs to connect to nA terminal [where n is an available numbered ground/return/(-)] When your signal is powered by the source device, a drive in this case, the signal is called either an 'active 4-20mA output, or a "4-wire" signal, not because there are 4 wires for the signal, but because there are 2 wires for the signal and 2 separate wires supplying power to the source device. Siemens uses the terminology '4-wire' for powered, active 4-20mA signals. So you need to look at the 4 wire wiring diagram 3-2 in the manual, not the 2-wire wiring diagram 3-1 because 2-wire refers to "passive 4-20mA" or signals that require a power supply to be wired into the loop to power the 4-20mA signal. I modified Fig 3-2 for clarity. https://i.postimg.cc/pTgkfqy6/4-wire-measurement-Dan-Rev1.jpg In my modified Fig 3-2 wiring diagram, above, I erased the connection to the Uv terminal that supplies DC power and the 2nd ground/return/(-) line. (You can see Uv (terminal 9) in Figure 3-1 in the Siemens manual powering a 2-wire field transmitter.) Your drive signal does not need DC power, so you do NOT use a Uv terminal. Refer to my Figure 3-2. where the 4-20mA speed signal (+) connects to In+ (n is an available numbered input) and the drive speed signal (-) connects to an nA terminal [where n is an available numbered ground/return/(-)]. |
| 10/12/2024 4:43 PM | |
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Posts: 2 Rating:
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I faced same problem This clear words solved it Thanks |
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