Flex 1794-ie8 analog input module problem - PLCS.net

smsp · September 29th, 2009, 02:17 AM

Hi guys,
Recently one of our AB Flex 1794-ie8 Series A analog input module has failed and we replaced it with a new one but a new module is Series B which need to be configured.The problem is we don't know how to configure this new module.Hope you guys can give some advice ... Thank in advance

Gil47 · September 29th, 2009, 02:59 AM

You are using an AB Flex 1794-ie8 connected to what processor
In most cases you just need to let the processor know what the module is in the I/O status now to do this this we need to know more detail if we are to help you.

smsp · September 29th, 2009, 03:22 AM

Thank Gil47,
Forgive me for not giving more detail ,
The AB Flex 1794-ie8 is connected to processor PLC5/40B through remote i/o adapter 1794-ASB.currently the ladder logic use BTR and BTW to read from AB Flex 1794-ie8 Series A but when we change to AB Flex 1794-ie8 Series B it seem the processor not reading from the module (the reading is zero and not changing).I read through the manual and it mention we have to configure the series B module but it doesn't show how to do it.Do we need other software or just use RSlogix5? .

Tq.

Mickey · September 29th, 2009, 09:35 AM

Post your .RSP file ( zip it first). Tell us where the module is located.
Is the module configured in the I/O configuration? PLC5's don't require this but it sure helps if you do it.
If the module is in the I/O configuration then it can be set up through the BTW/BTR instruction. ( double click on it). If not then you will have to manually set up the configuration words. See manual for this.

Link to the manual

http://literature.rockwellautomation...m002_-en-p.pdf

OkiePC · September 29th, 2009, 09:53 AM

The existing BTW is used to send the configuration to the module. The BTR is used to read the analog values from the module.

Are you sure that the BTW has executed after the module was replaced? If in doubt, you may want to edit the logic to make the BTW true (at least temporarily). The series B module has a couple of new features but should still work with the original BTW config....that is if it was properly set up for the old one...

Paul

smsp · September 30th, 2009, 01:54 AM

Attached is the BTR/BTW rung from our plant.I don't know if it was set up correctly because it was from the beginning of the plant set up back 1996 (i guess it was correct because so far it is working) .
[IMG]file:///C:/DOCUME%7E1/sam/LOCALS%7E1/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/DOCUME%7E1/sam/LOCALS%7E1/Temp/moz-screenshot-1.png[/IMG][IMG]file:///C:/DOCUME%7E1/sam/LOCALS%7E1/Temp/moz-screenshot-2.png[/IMG]

Duane Boston · September 30th, 2009, 02:28 AM

You have to take the cover off the module. Each channel (8) has jumpers to configure. If I remember right you can select current or voltage plus differential or single ended. The later denotes how the devices are wired.
I have had the same problem, I've had to read and learn, once set right it was plug and play so to speak.
Good Luck

Mickey · September 30th, 2009, 09:19 AM

Quote:

Originally Posted by Duane Boston

You have to take the cover off the module. Each channel (8) has jumpers to configure. If I remember right you can select current or voltage plus differential or single ended. The later denotes how the devices are wired.
I have had the same problem, I've had to read and learn, once set right it was plug and play so to speak.
Good Luck

The 1794-IE8 does not have jumpers. The current and voltage inputs are wired to different terminals. That I am aware of.

Can you show us a screen shot of the jumpers you are talking about?

smsp,
That picture really does not help us help you. Can you post the .RSP file? The whole thing.

smsp · October 26th, 2009, 12:08 AM

Dear all,
After much trying and reading the manual ,finally i manage to configure the 1794-IE8 module.As pointed out by Mickey that module doesn't have jumpers ,only the wiring connection differentiate between mA or Voltage input.Actually the problem is because the range selection is not set.For series A the range selection is not set (all bit in BTW is zero) and will read 4-20 mA but for series B it will read 0.So for series B the BTW word we have to set for example ch0 bit 8 =1 and bit 0=0 for the BTR to read 4-20 mA.
Anyway thank for all the feedback ,at least i got some idea on what when wrong with the configuration.

Thanks

September 29th, 2009, 02:17 AM	#1
smsp Member Join Date: Feb 2007 Location: Perak Posts: 12	Flex 1794-ie8 analog input module problem Hi guys, Recently one of our AB Flex 1794-ie8 Series A analog input module has failed and we replaced it with a new one but a new module is Series B which need to be configured.The problem is we don't know how to configure this new module.Hope you guys can give some advice ... Thank in advance

September 29th, 2009, 09:35 AM	#4
Mickey Lifetime Supporting Member Join Date: May 2003 Location: Palmdale,Ca Posts: 7,523	Post your .RSP file ( zip it first). Tell us where the module is located. Is the module configured in the I/O configuration? PLC5's don't require this but it sure helps if you do it. If the module is in the I/O configuration then it can be set up through the BTW/BTR instruction. ( double click on it). If not then you will have to manually set up the configuration words. See manual for this. Link to the manual http://literature.rockwellautomation...m002_-en-p.pdf __________________ Mickey If you want happiness for an hour-take a nap. If you want happiness for a day-go fishing. If you want happiness for a month-getmarried. If you want happiness for a year-inherit a fortune. If you want happiness for a lifetime-help someone else. ----- Chinese Proverb Last edited by Mickey; September 29th, 2009 at 09:38 AM.

September 29th, 2009, 09:53 AM	#5
OkiePC Lifetime Supporting Member Join Date: Mar 2005 Location: ENE of Nowhere Oklahoma Posts: 7,506	The existing BTW is used to send the configuration to the module. The BTR is used to read the analog values from the module. Are you sure that the BTW has executed after the module was replaced? If in doubt, you may want to edit the logic to make the BTW true (at least temporarily). The series B module has a couple of new features but should still work with the original BTW config....that is if it was properly set up for the old one... Paul __________________ It's not all the variables I am most concerned with, it's the undiscovered constants. "You can lead a horse to water but if he's got his head up his as$ he may die of thirst anyway."

September 30th, 2009, 02:28 AM	#7
Duane Boston Member Join Date: Sep 2005 Location: Ellington Posts: 3	It's in the manual !!! You have to take the cover off the module. Each channel (8) has jumpers to configure. If I remember right you can select current or voltage plus differential or single ended. The later denotes how the devices are wired. I have had the same problem, I've had to read and learn, once set right it was plug and play so to speak. Good Luck

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September 29th, 2009, 02:59 AM	#2
Gil47 Member Join Date: Apr 2007 Location: South Island, NewZealand Posts: 1,150	You are using an AB Flex 1794-ie8 connected to what processor In most cases you just need to let the processor know what the module is in the I/O status now to do this this we need to know more detail if we are to help you.

September 29th, 2009, 03:22 AM	#3
smsp Member Join Date: Feb 2007 Location: Perak Posts: 12	Thank Gil47, Forgive me for not giving more detail , The AB Flex 1794-ie8 is connected to processor PLC5/40B through remote i/o adapter 1794-ASB.currently the ladder logic use BTR and BTW to read from AB Flex 1794-ie8 Series A but when we change to AB Flex 1794-ie8 Series B it seem the processor not reading from the module (the reading is zero and not changing).I read through the manual and it mention we have to configure the series B module but it doesn't show how to do it.Do we need other software or just use RSlogix5? . Tq.

October 26th, 2009, 12:08 AM	#9
smsp Member Join Date: Feb 2007 Location: Perak Posts: 12	Dear all, After much trying and reading the manual ,finally i manage to configure the 1794-IE8 module.As pointed out by Mickey that module doesn't have jumpers ,only the wiring connection differentiate between mA or Voltage input.Actually the problem is because the range selection is not set.For series A the range selection is not set (all bit in BTW is zero) and will read 4-20 mA but for series B it will read 0.So for series B the BTW word we have to set for example ch0 bit 8 =1 and bit 0=0 for the BTR to read 4-20 mA. Anyway thank for all the feedback ,at least i got some idea on what when wrong with the configuration. Thanks

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