HELP!!! Can't Get 1771-OBD Modules To Go "Active"

I've got a 1771-L20E processor sitting in Chassis 0, with channel 1B daisy-chaining to another 12-slot chassis configured as chassis 3, and finally, a Panelview 1000 at the end of the RIO chain as "last chassis" (and terminated).
All chassis are set as 1-slot addressing.
Configured addresses are as follows:

Chassis 0: x:000/00 - x:010/17
Chassis 3: X:030/00 - x:037/17
Chassis 2 (Panelview): X:020/00 - x:027/17

Chassis 3 contains a 1771-ASB (series B) in the left-most slot.

Chassis 3 IO slot assigments are as follows:
Slot 0: 1771-IBD
Slot 1: 1771-OBD
Slot 2: 1771-IBD
Slot 3: 1771-OBD
Slot 4: 1771-IBD
Slot 5: 1771-IFE/A (set as single-ended)
Slot 6: 1771-IFE/A (set as differential)
Slot 7: 1771-IFE/A (set as single-ended)
Slot 8: empty
Slot 9: empty
Slot 10: empty
Slot 11: empty
The right-most slot contains a P4 power supply module.

All input modules as well as the ADC modules appear to be functional.

Here's the problem:
None of the output modules (1771-OBD) will go "Active". The 1771-ASB module's green "Active" indicator blinks at a slow rate, and the "Adapter Fault" and "I/O Rack Fault" indicators are always OFF.

I have tried everything I can think of. I'm stumped!

Thanks,
James
--
James R. Graham
Controls Engineer - IU Cyclotron Facility
email: [email protected]

Have you checked the dip switches on the all the chassis?

Yes, I've checked and re-checked, hoping to find something that would make me feel like an idiot...to no avail. Dipswitches all appear to be correct.

Jim
--

Have you added the Subroutines to the Main Ladder?

Subroutines? There are no additional subroutines required. All additional rack 3 I/O was added to existing code. Input modules in rack 3 are functional, and all input transitions are seen by the code. Analog input to the three 1771-IFE/A modules is also there. The only thing missing is "Active" outputs (which are also in the running code).

Was the code added "On-Line"? I have added logic online to a PLC5/20 CPU that would behave as you decribe. Only upon making changes offline and attempting to download into the CPU would the compiler tell me that I was out of controller memory, which is why none of the outputs would tdurn on.

No. The code was added offline, then downloaded. I've just re-downloaded again, and still have the problem. One thing I'm not sure about...
In RsLogix 5's IO configuration screen, I've got "Chassis_2" config. fields set as follows:

I/O channel: "1B - <I/O Scanner>"
Chassis Type: "1771-A3B (12 slots)"
Adapter: "1771-ASB Series B"
Inh: not checked
Res: not checked
Rack Addressing: "1 slot"
Rack: "3"
Group: "0"
Span: "3/0 - 4/3"
Complementary: "NO"

Now, I originally did not have a "Chassis Type". Instead, under Channel Configuration, I did an Autoconfigure, which added the following to the Channel 1B listing:

Rack: 3
Group: 0
Size: FULL
Range: 030-037

Since the 3rd rack is RIO'd via a 1771-ASB, and since the AutoConfig added the 3rd rack to the list, I didn't have a second A3B chassis added to the IO Configuration table. So I added another chassis to the same line that contains the I/O Channel "1B - <I/O Scanner>" in the I/O configuration Chassis Table.

It's not clear that this is necessary, but if I DON'T add the chassis, I do not get the Chassis configuration screens that allows me to define what modules go in which slots.

I'm still not sure about this one. In any case, it doesn't seem to make a difference. I simply cannot make outputs in rack 3 "active".

Thanks,
Jim
--

The flashing green 1771-ASB network LED definitely makes it appear there's something still in Idle mode.

The placement of the I/O modules (I/O/I/O) suggests 2-slot addressing, but you say you set it up for 1-slot addressing. The fact that the Autoconfigure returned Rack 3 Full Rack only, instead of adding Rack 4 1/2 Rack as well, makes me think there's something about the DIP switch settings that's incorrect.

Can you post the 1771-ASB series letter and the actual DIP switch settings ? It's been a while since I did 1771 on RIO.

That "last chassis" setting in the PanelView reminds me that most people misinterpret that setting. It doesn't have anything to do with the position of the adapter in the RIO daisy-chain, nor does it indicate that the device is the highest-numbered Adapter on the network. All it indicates is that the device is the last fractional logical rack device for a given Rack number.

For example, if you have three FLEX adapters, each with two 16-point I/O modules:

Adapter A: Rack 2, Groups 0,1
Adapter B: Rack 2, Groups 2-3
Adapter C: Rack 2, Groups 4-5

and if there's no Rack 2, Groups 6-7 device, then Adapter C is the "last chassis". This really only influences PLC-2 and maybe Classic PLC-5 controller RIO scanners.

Ken,
Thanks for the reply.
The 1771-ASB is series "B".
The 1771-ASB dipswitches are as follows:

Sw. #
1 - ON
2 - ON
3 - ON
4 - ON
5 - OFF
6 - OFF
7 - ON
8 - ON

And the short 4-position dip:
1 - OFF
2 - OFF
3 - OFF
4 - OFF

The Rack 3 chassis DIPS:
1 - OFF
2 - ON
3 - OFF
4 - OFF
5 - ON
6 - OFF
7 - OFF
8 - OFF

The Rack 0/1 chassis DIPS:
1 - OFF
2 - OFF
3 - OFF
4 - OFF
5 - ON
6 - OFF
7 - OFF
8 - OFF

Panelview Settings:
Rack Number - 2
Rack Size - Full
Starting Group - 0,1
Pass Thru Enabled - YES
Last Chassis - YES
BAUD - 115.2k

Cheers,
Jim
--

Been awhile since I messed with a 1771-ASB, but I seem to recall there is a configuration plug on the side for setting up 32 point addressing. You don't have those enabled by accident do you?

Well, the 1771-ASB Series B is definitely configured correctly according to the User manuals that I have, which is publication 1771-UM001 February 2000.

SW1 11110011 sets it as Rack 3, Starting Group 0.
SW2 0000 Sets the baud rate at 115.2 kb/s.

The Rack 3 chassis DIP switch settings indicate:
SW 1 = OFF De-Energize outputs when fault detected.
SW 2 = ON Processor can restart faulted adapter
SW 3,4 = Always OFF
SW 5,6 = ON, OFF = 1-Slot Addressing
SW 7 = Always OFF
SW 8 = OFF = Chassis contains the highest addressed fractional rack device.

Since this is a PLC-5/20, it can scan 8 Remote I/O logical Racks, so there's no problem defining a Rack 04.

I'm surprised, though, that the 1771-ASB didn't return both Rack 03 Full and Rack 04 1/2 Rack when you ran the AutoConfig.

With the blinking green Adapter LED, this feels like a rack size mismatch to me, but I'm rusty enough in RIO configurations to know if you should be able to run a 1-Slot Addressed 12-slot chassis as just 1 logical Rack.

Has RA Tech Support had a shot at this ? They have some real 1771 experts who are fresher on this than I am.

Hmm,
There IS a jumper located inside the module (you have to remove the cover to get to it). However, the jumper is neither labeled on the board nor documented in the manual.

Jim
--

bkstump said:

Hmm,
There IS a jumper located inside the module (you have to remove the cover to get to it). However, the jumper is neither labeled on the board nor documented in the manual.

Jim
--

Click to expand...

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1771-um001_-en-p.pdf

PDF page 16 (2-2)

Shouldn't be your problem, but something to check nevertheless. Even if on 32pt, should still work.

I've checked page 2-2 of the manual, as you indicate above. However, this module does not have an access hole in the left side of the module. Moreover, if I remove the cover, there is a jumper on the upper left corner of the lower 1/3 of the circuit board. There are lands on the pc board for three jumpers, but only one is installed...the top one. I suspect this is because the manual primarily covers series "E" while my board is a series "B".

Thanks,
jim

Can a 5/20 address a 4th rack?

A twelve slot chassis with single slot addressing would need the first half of rack 4, would it not?
You may have to use 2-slot addressing after all with that processor and I/O quantity.

I have not used a 5/20E, but I think the 5/20 was limited to 4 logical racks of IO. (0=local, 1-3 remote)