ControlLogix and PLC5 Remote I/O Rack

tgoulding

Member
Join Date
Jan 2005
Posts
84
We have a 12 slot PLC5 Chassis. We've removed the PLC5 processor and replaced with a 1771-ASB, chassis set for 1 slot addressing. We are using this chassis and it's I/O as a remote rack for ControlLogix, comms via a DHRIO card channel B, in ControLogix chassis. The I/O in the PLC5 rack is as follows;

1771-ASB
DC Input 16 Channel (Rack 0, Group 0)
DC Input 16 Channel (Rack 0, Group 1)
DC Input 16 Channel (Rack 0, Group 2)
DC Input 16 Channel (Rack 0, Group 3)
DC Input 16 Channel (Rack 0, Group 4)
DC Output 16 Channel (Rack 0, Group 5)
Empty Slot (Rack 0, Group 6)
Empty Slot (Rack 0, Group 7)
Analog Input Card (Rack 1, Group 0)
Empty Slot (Rack 1, Group 1)
1771-QRD (Rack 1, Group 2)
Empty Slot (Rack 1, Group 3)

All the Digital I/O are fine as set up automatically as controller tags when RIO Adapter added to DHRIO card in I/O configuration.
The analog inputs are also fine, accessed using message block (i.e Block Transfer Write, Block Transfer Read), Path - DHRIO1 (card name), Module Address - RIO, Channel - B, Rack - 1, Group - 0, Slot - 0.
The 1771-QRD 'Pulse Flowmeter Module' which is messaged in a similar fashion to the analog card is not working, rate and total values are not updating.
We have tried this module in a test chassis with a PLC5 processor and it is working fine.
No errors on card or software, message block EN and DN flags not toggling. The 'Prog' LED on front of module is not lit, this should be flashing if block transfers are working.

Anybody have any ideas, would appreciated any help on this.
 
In the online I/O tree, is there a Yellow Exclamation mark associated with this card?

Also, this is a 'back to basics' statement, the code associated with this card is being scanned and/or the Clgx MSG instruction is set up identical to the BTR/BTW in the PLC5?
 
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Only the Digital I/O are listed in the I/O tree, neither the analog nor the QRD are listed here. The analog functions correctly? Do they need to be listed in the I/O tree. If so should I add an RIO adapter for Rack 1 even though in the same chassis as Rack 0.
To answer you other queries yes the code is being scanned and yes the MSG instructions are set up as per the PLC5.
 
Only the Digital I/O are listed in the I/O tree, neither the analog nor the QRD are listed here. The analog functions correctly? Do they need to be listed in the I/O tree. If so should I add an RIO adapter for Rack 1 even though in the same chassis as Rack 0.

You should add only 1771ASB to I/O configuration, don't put any I/O modules.

Add one ASB per each logical rack even you have only one ASB in this chassis.

In your case it should look like this:

DH1.jpg


Message Path should be to Rack 1, Group 2, Slot 0
 
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Contr_Conn said:
You should add only 1771ASB to I/O configuration, don't put any I/O modules.

Add one ASB per each logical rack even you have only one ASB in this chassis.

In your case it should look like this:

DH1.jpg


Message Path should be to Rack 1, Group 2, Slot 0


rio_tree_1.jpg


I always put the I/O in the tree, that way If one module gives an issue I know which one it is
 
Hi Contr Conn

Are you saying that I shouldn't have listed the Digital I/O

Also from your post it looks as if I should add another RIO adapter as rack 1 for the last 4 slots in PLC5 chasis, is this correct.

As a matter of interest I also moved the card to one of the empty slots i.e. Rack 0 Group 6 and the message blocks still failed to function.
 
I always put the I/O in the tree, that way If one module gives an issue I know which one it is
PLC5 and ASB have no idea if module is installed or not and really don't care about them. So adding modules is useless.

Also from your post it looks as if I should add another RIO adapter as rack 1 for the last 4 slots in PLC5 chasis, is this correct.
Yes, you will not get solid Active light on ASB if sizes are incorrect. But check dip switch settings, you may have it set as "ignore last 4 slots"
Why BT does not work in slot 6?
What error?
I am not familiar with this specific module so get user manual and check BT sizes.
 
Contr_Conn said:
PLC5 and ASB have no idea if module is installed or not and really don't care about them. So adding modules is useless.

Yes, you will not get solid Active light on ASB if sizes are incorrect. But check dip switch settings, you may have it set as "ignore last 4 slots"
Why BT does not work in slot 6?
What error?
I am not familiar with this specific module so get user manual and check BT sizes.

This is a Contrologix app.
Ian
 
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This is a Contrologix app
I know this is ControlLogix, but in 1771 chassis ASB (or PLC5) don't really care what modules installed and if they are working or not. So Controllogix will never know if module fails
 
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Contr_Conn said:
I know this is ControlLogix, but in 1771 chassis ASB (or PLC5) don't really care what modules installed and if they are working or not. So Controllogix will never know if module fails

so you are saying then in a RIO rack if , say a Basic Module fails, the entire rack will show the yellow exclamation mark giving no indication which module failed?

Ian
 
curlyandshemp said:
typically the MSG instruction needs to see a false to true transition to work


msg_1.jpg

I followed the example in the '1771-QRD Pulse Flowmeter Module' user manual, publication 1771-6.5.73. In this the MSG instructions do not have a false to true transition.
 
Contr_Conn said:
PLC5 and ASB have no idea if module is installed or not and really don't care about them. So adding modules is useless.

Yes, you will not get solid Active light on ASB if sizes are incorrect. But check dip switch settings, you may have it set as "ignore last 4 slots"
Why BT does not work in slot 6?
What error?
I am not familiar with this specific module so get user manual and check BT sizes.

Again as previously posted I followed the example in the '1771-QRD Pulse Flowmeter Module' user manual, publication 1771-6.5.73. I followed all the BT sizes as per the manual.
 

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