adding RIO module on PLC5

I am having trouble adding an output modules to a remote io rack on a plc5
the processor is PLC5/80E it has 6 full RIO racks and 2 3/4 racks I am trying to add 2 output modules, the rack i am adding to has 6 pulsed input modules already.
Complementary IO is not enabled in the channel config of the scanner or the dip switches of the adaptor.
Have tried auto config and manual but it still can't see the new outputs any ideas much appreciated.

dullspark,

Although you have a PLC-5, what I/O are you using?
is it 1771 I/O or is it flex?
If it is 1771 then you usually do not have to configure the PLC except for documentation purposes.

Can you give us more information on the layout and type of I/O and any other relevant information?

Welcome to the Forum !

What hardware style is your "remote rack"; is it 1771 type, or 1794 FLEX type, or something else ?

What "rack size" is the existing adapter you are adding modules to using ?

An adapter with six modules is probably a "3/4 rack" now, so adding two new modules will probably make it a "full rack". Depending on exactly what product you're using, you might have to change some DIP switches.

Generally you will "see" the new modules because the adapter starts behaving as a larger I/O memory size. They don't automatically show up in a graphical view.

Post more information about your adapters and configuration and addressing, and folks should be able to help.

the remote rack adapter is a 1794-ASB flex IO and the rack is showing up as 3/4 on the scanner channel properties screen with an address range of 070 to 075 (so I am trying to add 076-077)
the 6 modules already in place are 4ch pulse counter modules (1794 also) and i am trying to add 2 16 bit output modules

Is there already an adapter that starts at RIO memory location Rack 7, Group 6 ? Maybe there's an overlap conflict.

In general, a FLEX I/O adapter sets its Rack Size based on which modules it detects at power-up.

I would start by manually changing the PLC-5 scanlist so that Rack 7 is a Full Rack, then check the powerup sequence of the adapter and the I/O modules to be sure the Adapter recognizes them all.

are you sure that the new terminal blocks are "powered up" ??? ...

if I remember correctly, some 1794 modules need 24VDC supplied from the "preceding" terminal block (two short jumper wires for each new block) before they'll do anything ...

specifically, the "ribbon cable" connection is not always enough - even for just communicating ...

DISCLAIMER: it's been quite awhile since I've worked with this type of system ... but my memory tells me that this could be your problem ... I can confirm this when I get back to the lab - but I'm home today and don't have my 1794 equipment handy ...

TIP: don't bet the rent on my memory - but this shouldn't take you too long to check out ...

if you'll give us the specific catalog numbers of your hardware, then maybe we could help you nail this down ... right now we're just kind of guessing ...

all the RIO hardware is 1794 but I think "power up" is the bit I was missing as I have just been switching to program mode to configure the rack and have not powered down.
I will have to wait a couple of days to do this now as the system is in production.
Does anyone think the fact the other modules are 4ch counter modules is causing a problem?
Thanks for the help so far

the terminals are wired to 24v from the adjoining terminal block

In general you can physically remove and insert 1794 series modules under power, but I avoid attaching new Terminal Bases with the power on. The connectors are notably finicky, though after learning how to install them without brute force I've never had trouble.

The power cycle is almost certainly the issue.

dullspark said:

the terminals are wired to 24v from the adjoining terminal block

Click to expand...

There is an issue with this scenario.
If digital modules are placed within the same chassis as 1794-IP4 ones, separate 24VDC supply power needs to be provided for each module category.

Page 2-3 of :

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1794-um016_-en-p.pdf

thanks everyone for the help but may never know which fix worked just got laid off maybe should have got on here earlier
anyone need a sparky