Panel View with Scanner Module 1771-SN


Thread Starter

Juan de Araujo

Does anybody have used a Remote I/O Panel View comunicating with a PLC-5 through a Scanner Module 1771-SN ? Is it true that the panel view can access only 8 input (I) and 8 output (O) bits ?

Juan de Araujo
Saga Engenharia.

Michael R. Batchelor

You don't have to have a 1771-SN unless you have one of the little PLC-5s. You can use the port on front. Either way it can be just a device out on the RIO. And you can use more than 8 bits, too. When you set up the Panelview attributes tell it to use a half rack, 3/4 rack, or full rack and you can make the buttons on the panelview appear on the I/O table in that address space.

For example, the F1 button can be I:1/16 on screen 0 and I:2/16 on another screen.


In discrete transfer (memory mapped I/O), that's really at least eight 16-bit words in and eight 16-bit words out (one rack, with all kinds of
options). The 1771-SN cannot relay a block transfer, but it can block transfer a four rack space back to the 5. Details on the PanelView depend upon its catalog number.

The 1771-SN was popular with Mini-PLC-2s, but not seen much with PLC-5s.

It's usually a better idea to upgrade the PLC-5 rather than add the sub-scanner. Have you added the 1771-SN yet?

Larry Lawver
Rexel / Central Florida

I'm assuming that if you are ussin a 1771-SN you want to conec via RI/o. If so, the you mut Know tht there are two ways of comunication with this scenario you mentioned. 1) Adrressing only IO, wich means that you can only transfer the
amount of I and O's that the size of rack choused permit.
2) Via block transfers. Using this metod you will be able to transfer a big range of data.

The 1771-SN module or Sub-Scanner allows one to extend the I/O addressing of a PLC-5 (Original or Enhanced) with an additional 7 racks. The
sub-scanner communicates to the PLC-5 via the backplane; therefore you will have to setup block transfers functions and set the appropriate
1771-SN dip switches in order to transfer data between the PLC-5 and the 1771-SN module. You have to configure the PanelView to match the
settings of the rack assigned on the 1771-SN module. To achieve the maximum data transfer size set the PanelView and associated I/O Channel
for a FULL Rack. This will allow you to support 8 Words of I/O (or approximately as the first word may be used for control status check the
documentation). The documentation for the 1771-SN maybe incorrect in that it actually scans racks 0 to 6 not 1 to 7 you should check this.
Allen Bradley may have fixed this error in their documentation ??? Good Luck.

Anthony Kerstens

8 in and 8 out for I/O configured as a rack on RIO. You can transfer a lot more using block transfers to the panelview.

Anthony Kerstens P.Eng.
One gotcha with the 1771-SN and PLC-2 controllers is that the PLC-2 doesn't
have a "Rack 0" I/O addressing space, which offsets it's mapping of RIO
addresses by one Rack number versus the equivalent when scanned with a

If you were using a Standard PanelView (like the model 550, 900, or 1000),
you would set the PanelView for one Rack number lower than you expect it's
data to show up in the 1771-SN. If the PanelView is set for Rack 02, it
will show up in the Rack 03 data space in the 1771-SN.

You will be able to scan the PanelView as one "full logical rack": Eight 16-bit Input Words and eight 16-bit Output Words .

The original poster didn't include what model of PLC his controller is (PLC-2, PLC-5 Classic, PLC-5 Enhanced) or what type of PanelView (Classic,
Enhanced, or Standard) he's using so more addressing info probably can't be offered.

Ken Roach
A-B Seattle