Jogvan Simun Sevdal Posted January 25, 2019 Report Share Posted January 25, 2019 Hey I just sat down with a brand new SM70-J-RA22 and started programming. I am going to use my AN 2, In6 for reference as to know the position of my valve. 4-20mA. I set the hardware jumper to the correct position for current. And now I wanted to test to see if it works. I want to test with my I/U simulator-tester (MS4201) but I get no raw values into my plc only flickers between 2 and 3. When I try to simulate the 4mA input I only read 3,58ma and when I try to simulate 20mA I only get 5,38mA. When I use the wheel on my instrument to turn 4-20mA upp and down nothing happens until I turn it almost all the way down and there I can go up and down from 0-5,38mA and on my plc the values change up and down from 0-3 accordingly . What can be the problem? I measure 6,6k ohm between 0V and terminal 9(in6). J.S Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 Have you confirmed your wiring matches the Unitronics Installation Manual? Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 Hey yes as far as I can see and double checked the wiring should be ok. The elma MS4201 calibrator instrument that I use can have active or passive calibratioin. Two wires one black (-) and one red (+) . The positve to 24V and the negative to the terminal is the way I have tested it. J.S Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 31 minutes ago, Jogvan Simun Sevdal said: When I try to simulate the 4mA input I only read 3,58ma and when I try to simulate 20mA I only get 5,38mA. How are you measuring this? If you're reading this on the PLC then post the software you have running in the Samba. Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 I see this on my calibrator not in the plc, sorry if unclear. As it is a analog in I would assume that if I put in 4mA I should read some raw values in my plc. And also if I put in 20mA I should read a higher value in my plc. Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 2 minutes ago, Jogvan Simun Sevdal said: As it is a analog in I would assume that if I put in 4mA I should read some raw values in my plc. And also if I put in 20mA I should read a higher value in my plc. Depending on how you have set up the HW Configuration, you should see a value from 819-4095 or 3277-16383 for the input range 4-20mA. You can then linearize that number from 4-20mA or 0-100% or whatever you need. Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 yes this was my understanding also, but what else can there be wrong from my side. I have tried to make a new project and it seems that the only scale I have is from 0-3,54mA which I can regulate with my calibrator. Where 4 mA on my calibrator is 3,54mA and also 20mA is 3,54mA. Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 Is there something else I am missing, I have moved the jumper from A to B this to make it for voltage/current measurement. Is there something else I have to change/activate before my analog input work? Out of couriosity I tried to move the jumper back just to check if my digital input works for in6/an2 and it does. I took the risk and tried to put 4mA in a digital input, and it behaves just the same as the analog2, only shows 3,54mA (some sort off error state?) It leaves me to think is it possible that even If I move the jumpers from A to B it does't recognises it as an analag input? Does it matter how I download my program? Quote Link to comment Share on other sites More sharing options...
MVP 2023 Flex727 Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 It's still not clear to me how you KNOW how many mA are being fed to the PLC. You said "on my calibrator, not in the PLC". If so, why are you troubleshooting the PLC? Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 32 minutes ago, Jogvan Simun Sevdal said: I took the risk and tried to put 4mA in a digital input, and it behaves just the same as the analog2, only shows 3,54mA (some sort off error state?) It leaves me to think is it possible that even If I move the jumpers from A to B it does't recognises it as an analag input? 1 hour ago, Jogvan Simun Sevdal said: I set the hardware jumper to the correct position for current. When you're asking questions about setting up hardware, you need to be very specific about which jumpers you moved so we know that you know how to read the manual. When you use this kind of verbiage in a post you're projecting that you have complete confidence in your hardware configuration. Yet a new PLC out of the box isn't working, so something must be wrong. So with that said, do you have both JP8 and JP9 in position B? Also - you have to configure the hardware in your program. Post your code so we can see you've done that correctly. Joe T. Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 Sorry for being unclear. My problem is that when I give my analog input 4 or 20ma with my calibrator, I should still read 4 or 20mA or whatever in between on my calibrator ehile still connected to the plc. But instead it drops to 3,54mA as if I am not allowed to use the analog input or it inhibts me somehow. It should not affect my measurement being connected to the plc. This calibrator is a mA giver. And in the plc I can see no change for the input value (flickering2-3) nor prior, while or after my test Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 This is basic circuit troubleshooting. I swear nobody knows how to do this anymore. Here are the specifications for your PLC- https://myzone-kza3sadj.netdna-ssl.com/wp-content/uploads/2015/12/SMXX-J-RA22-SPEC-2-16.pdf Look on page 2 under "Analog Inputs" - the input impedance is 37 ohms. When you set the jumpers for current inputs you are adding a shunt resistor across the voltage input to convert current to voltage. Put your calibrator into source mode and drive the input directly. A typical loop impedance is 250 ohms. Unitronics is much lower than this, so you shouldn't have a problem. If you can't get above 3.5 mA then what you're connected to has too large of an impedance. Power down the PLC and put an ohmmeter between AN 2 and 0V. You should see about 37 ohms. You may have blown something up playing with it. Configure AN 3 as a current input and measure that with your meter. Joe T. Quote Link to comment Share on other sites More sharing options...
Jogvan Simun Sevdal Posted January 25, 2019 Author Report Share Posted January 25, 2019 14 minutes ago, Joe Tauser said: This is basic circuit troubleshooting. I swear nobody knows how to do this anymore. Here are the specifications for your PLC- https://myzone-kza3sadj.netdna-ssl.com/wp-content/uploads/2015/12/SMXX-J-RA22-SPEC-2-16.pdf Look on page 2 under "Analog Inputs" - the input impedance is 37 ohms. When you set the jumpers for current inputs you are adding a shunt resistor across the voltage input to convert current to voltage. Put your calibrator into source mode and drive the input directly. A typical loop impedance is 250 ohms. Unitronics is much lower than this, so you shouldn't have a problem. If you can't get above 3.5 mA then what you're connected to has too large of an impedance. Power down the PLC and put an ohmmeter between AN 2 and 0V. You should see about 37 ohms. You may have blown something up playing with it. Configure AN 3 as a current input and measure that with your meter. Joe Yes i will try that Quote Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted January 25, 2019 MVP 2023 Report Share Posted January 25, 2019 Jogvan, on top of the excellent advice Joe T has given, are you sure you are using the MS4201 correctly? Have you used it before and fully understand it's various operations? I've read the manual and think that some of the descriptions are a bit ambiguous and the various operations need to be physically checked and understood before hooking it up for proper use. And maybe the battery in the unit is flat? cheers, Aus Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.