Using A-B IFM Terminal Blocks with SLC TTL I/O Modules?

[sanger]

Has anyone used the AB IFM Terminal Blocks and cables with ControlLogix TTL I/O modules. AB says that they do not support the IFM wiring system on TTL I/O but I can see no reason why it would not work. This is the configuration we are considering.

I/O Modules:
1756-IG16 and 1756-OG16

IFM Cables/Terminal Blocks
1492-IFM20F
1492-CABLE025X

Any comments on why this would/would-not work.

 

[Ron Beaufort]

first things first ...

before we go too far with this ...

you're saying "SLC" - but you're giving 1756 (ControlLogix) part numbers for the I/O modules ... SLC uses 1746 or 1747 type part numbers ...

are these just typographical errors - or something else? ...

 

[sanger]

My mistake. I typed SLC instead of CLX. I corrected the original message.

 

[OkiePC]

I am not familiar with TTL modules and can't quickly access the devices you are referencing (post links please).

With that said, If they're only connectors, it should work, but you may need to modify the pin-out or carefully choose which blocks and cables to buy. If there are passive circuits on the blocks, I would think it's a no go with low current 5vdc signals. I have several SLC connection systems and have had no problems with them except extra panel space and expense, but have not used them with the Logix family.

They will speed wiring, but take more space and cost more for hardware. I like the extended terminal block housings available for 1756 I/O. They are cheaper and pretty easy to wire.

 

[The Plc Kid]

What are the primary uses for TTL cards anyway? I have never ran across one to date.

 

[Ron Beaufort]

they're for Transistor-Transistor-Logic applications (TTL) ... in most cases this boils down to low voltage (about 5 VDC is usual) and very low current ...

a common example would be a robot whose controller board accepts these types of signals to "bias" or "fire" its input circuits ... something like a signal to run program #1 ... or go to "home" position ... etc. ...

think: from one transistor to another transistor - without a relay, etc. in between ...