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chuahyc
Junior
Joined: 05 Dec 2012
Posts: 6
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 Posted: 09/12/2012 00:21 Post subject: Minimum Voltage to drive 4-20ma 4 wire current input |
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Hi,
May i know the how to know the minimum voltage to drive a analog input card. I'm connected to 4-20mA channel for 4 wire, supply voltage from transmitter is 14.4V. From the S7, It not able to detect the current feedback from the transmitter.
Please Help. thanks. |
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ratko
Member 3
Joined: 20 Jul 2012
Posts: 524
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| Posted: 09/12/2012 16:04 Post subject: Re: Minimum Voltage to drive 4-20ma 4 wire current input |
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| chuahyc wrote: | Hi,
May i know the how to know the minimum voltage to drive a analog input card. I'm connected to 4-20mA channel for 4 wire, supply voltage from transmitter is 14.4V. From the S7, It not able to detect the current feedback from the transmitter.
Please Help. thanks. |
What type of SM331 Module are you using..?
and eventually what transducer..?
Did you choose the correct parametrization for AI Card?
If your input is drive in current the voltage do not count....you only need to supply the transducer correctly...
Check the manual:
https://a248.e.akamai.net/cache.automation.siemens.com/dnl/jU/jU0OTk5NQAA_18972936_HB/s7300_sm_331_teil3_getting_started_en-US.pdf |
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chuahyc
Junior
Joined: 05 Dec 2012
Posts: 6
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| Posted: 09/12/2012 21:31 Post subject: Re: Minimum Voltage to drive 4-20ma 4 wire current input |
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[quote="ratko"] | chuahyc wrote: | Hi,
What type of SM331 Module are you using..?
and eventually what transducer..?
Did you choose the correct parametrization for AI Card?
If your input is drive in current the voltage do not count....you only need to supply the transducer correctly...
Check the manual:
https://a248.e.akamai.net/cache.automation.siemens.com/dnl/jU/jU0OTk5NQAA_18972936_HB/s7300_sm_331_teil3_getting_started_en-US.pdf |
I'm using 6ES7331-7KF02-0AB0, it's a E&H transducer for turbidity, it is active current output, supply 15Vdc and can support up to 500 Ohm Load Register.
For my Analog Input card, Module setting is C (4-Wire), Hardware configuration is 4DMU , 4..20 mA.
any idea why i cant get the analog input signal?
Thanks for helping |
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ratko
Member 3
Joined: 20 Jul 2012
Posts: 524
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| Posted: 09/12/2012 22:28 Post subject: Re: Minimum Voltage to drive 4-20ma 4 wire current input |
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[quote="chuahyc"] | ratko wrote: | | chuahyc wrote: | Hi,
What type of SM331 Module are you using..?
and eventually what transducer..?
Did you choose the correct parametrization for AI Card?
If your input is drive in current the voltage do not count....you only need to supply the transducer correctly...
Check the manual:
https://a248.e.akamai.net/cache.automation.siemens.com/dnl/jU/jU0OTk5NQAA_18972936_HB/s7300_sm_331_teil3_getting_started_en-US.pdf |
I'm using 6ES7331-7KF02-0AB0, it's a E&H transducer for turbidity, it is active current output, supply 15Vdc and can support up to 500 Ohm Load Register.
For my Analog Input card, Module setting is C (4-Wire), Hardware configuration is 4DMU , 4..20 mA.
any idea why i cant get the analog input signal?
Thanks for helping |
It happens if you forget to rotate the measuring range module to the right position and when your hardware configuration doesn't match actual configuration.
1- Rotate the measuring range module to the correct position (Look at attachment).
2- Connect the signal wires (4-20mA) to a configured channel.
3- Supply your transmitter with 24VDC(15VDC) externally and make sure your device is active.
4- Put a multimeter in series between the device and the module and see if current varies according to transmitter measurement.
5- Make sure that your hardware configuration matches your connection
6- Download your hardware configuration.
7- Check the analog value in a your program or in VAT and look if it's varying or not.
8- If you still face problems, Open hardware configuration window, Station>Open ONLINE and click on module and check if it has something wrong.
Getting started manual:
http://ftp.gongkong.com/UploadFile/datum/2008-7/2008072009410900001%28SM331_Getting_Started_Teil1_e%29.pdf
Attention:
Since configured inputs can remain unused because of the channel group
generation, you must take note of the following deosebit characteristics of these inputs to enable the diagnostic functions on the used channels.
• Measuring range 1 to 5 V: Connect the unused input in parallel with a used input of the same channel group.
• Current measurement, 2-wire transmitter:
There are two ways to use the channels:
a) Leave the unused input open and do not enable diagnostics for this
channel group. Otherwise, if diagnostics are enabled, the analog module
triggers a single diagnostic interrupt and the SF LED of the analog module
comes on.
b) Connect the unused input with a resistance of 1.5 to 3.3 k. You may then
enable diagnostics for this channel group.
• Current measurement 4 to 20 mA, 4-wire transmitter: Connect the unused input in series with an input of the same channel group. |
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chuahyc
Junior
Joined: 05 Dec 2012
Posts: 6
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| Posted: 16/12/2012 07:08 Post subject: Re: Minimum Voltage to drive 4-20ma 4 wire current input |
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Thank You for helping.
Problem solved the day after post.
the problem is the panel supplier didn't loop the internal common between each channel. When voltage higher than 15Vdc, it able to work, but for those lower than 15Vdc, it cant work. After I loop those channel, it work fine again. Thank you. |
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