How to config PLC5/40 and newer remote IO with Flex IO 32 points

I use PLC 5/40 and try to use Flex IO as a remote IO with 32 point IO modules.
Flex layout is show below
1. 1794-ASB/E
2. 1794-IV32
3. 1794-OV32

I use standard 32 pt mode. (Dip Switch S1-1 is off)

On RSLogix5 PLC5 see only 16 LSB points of module.
It doesn't see 16 MSB points of 32 modules.

In 1794-ASB/E, it said if we set S1-1 to off, we can use standard 32 pt mode but you need to use rack number 40 and upper which is not support by PLC5.

Is this true?

If the answer is yes, Is there any way to config 32 point modules work with PLC5?

By the way, Is there anyone used to try to use block transfer with 32 points digital module?

Welcome to the Forum !

What is the "Rack Size" you configured in the PLC-5 controller ?

To use Standard 32-Point Mode with those two modules, the 1794-ASB adapter should be configured as a "1/2 Rack".

The symptom you describe of being only able to see the lower 16 points of a 32-point Input module is typical of having the module mis-configured for Standard 16-point mode or Compact mode.

The "Rack 40" addressing you are referring to is for Complementary mode; you do not need Complementary mode for this application.

To confirm that you have configured the 1794-ASB correctly for 32-Point Standard mode, post all of the DIP switch settings you have made for the module.

Ken Roach,

Thank you for your answer.
Here below is our DIP SW setting in ASB

IO GROUP = 0
S1-8 = ON
S1-7 = ON

COMMUNICATION RATE = 230K
S2-4 = ON
S2-3 = OFF

STANDARD 32 PT
S2-8 = ON
S2-5 = ON
S1-1 = ON
S2-3 = OFF
S2-4 = OFF

RACK NUMBER = 4
S1-6 = ON
S1-5 = ON
S1-4 = OFF
S1-3 = ON
S1-2 = ON
S1-1 = ON

I'm not sure on S1-1 configure if it correct.

slot addressing is 1/2

Is there any incorrect setting of DIP SW?

Oh I forgot about Rack Size.

In PLC5, i config Rack Size to 1/2.

Another question that important to me is
Is PLC5/40 can use 32 points module via 1794-ASB/E?

Someone, please confirm this question to me.

Thank you for posting that detailed information.

The setting that puts the 1794-ASB/E into "32-point" mode is the Data Rate switches.

Set both S2-3 and S2-4 to OFF and cycle power to the 1794-ASB/E with the scanner active.

This will place the Adapter in 32-point mode and allow it to auto-detect the RIO network speed.

Thank Ken for your answer.
S2-3 and S2-4 is very important as you said.
It use to enable 32 pt module.
Now we can use Standard 32 pt mode.

By the way, Input and Output data image is consume on different group on this config.

Is there any way to use 32 pt Input and Output with same group number without using complementary mode?

I mean can we config 32 point module as a slot paring which can be done by 1747-SN module.

Thank you for posting the follow-up. I am glad to hear you got it working.

Is there any way to use 32 pt Input and Output with same group number without using complementary mode?

Click to expand...

No. The only operating modes of the 1794-ASB/E that support 32-point modules are 32 Point Standard and 32 Point Complementary. There is no 32-point Compact mode.

Thank you Ken for your prompt response.

I now quiet clear about ASB/E.

So, in conclusion, If we need fully compatible with old remote IO of PLC5, we should select 16 pt module instead of 32 pt module.

Thank again.

In general, yes.

16-point modules give you the best logical memory density, variety, and compatibility with PLC-5 Classic, PLC-5 Enhanced, SLC-500, and ControlLogix scanners.

32-point modules give you better physical density for installations with a small footprint.