Micrologix 1100 IP Address

[cesar22]

How can I know the IP Addres on the plc if the lcd doesn't turn on and I want to upload the program already in it. But I need the address to start communication

 

[Mickey]

Why not connect to the serial port?

 

[cesar22]

I don't have the serial cable at the moment

 

[parky]

download one of the IP scanners there are a number out there that are free like angryIP. Make sure that the ethernet is only connected to your pc if possible or you will get a long list of what's on the network.

 

[damica1]

None better than "Wireshark"!

 

[drbitboy]

Alternate 1 quick method, requires a Mac OS X system:


If you have a Mac OS X on the network (not likely, I know):

1. start a terminal window
2. Enter the command
   • arp -a

You should see a list of IP addresses paired with MAC addresses e.g.

? (192.168.1.112) at xx:yy:zz:aa:bb:cc on en1 ifscope [ethernet]

The MAC address (xx:yy:zz:aa:bb:cc) of the MicroLogix 1100 (ML1100) should be somewhere on PLC body and/or label; pair that with the IP address (192.168.1.112 above) on the same line in the [arp -a] output.




Alternate 2, requires a DHCP server with a web server, and a PC with a web browser on the same network:


If the ML1100 is getting its IP address via DHCP, you might be able to query the DHCP server; most routers that supply the DHCP service have built-in web servers




Alternate 3, requires a packet sniffer e.g. WireShark:


Filter for messages from the MAC address of the ML100; it will take a little decoding but the IP will be in an ARP packet that the ML1100 sends out every two minutes.




Alternate 4:

https://www.advanced-ip-scanner.com/

I make no warranties about whether that is a valid product or not; I loaded it on my Win10 VM so I don't care as the VM can be replaced.

TL;DR



Alternate 1 (Mac OS X and [arp -a]) is only anecdotal at this point, so it would be great if someone else could test this.


The MicroLogix 1100 sends out an Address Resolution Protocol-related (ARP) packet every two minutes, and OS X apparently listens and puts those in its ARP table. Unfortunately Window sdoes not do the same (or maybe it does, and my Window 10 VM guest on a Linux host with a bridged adapter does not).


I found these using [tcpdump] on my Linux box, and noticed the ARP result on my Mac; I suppose a Windows packet sniffer could do the same (WireShark?) i.e. leave it running and filter for packets by the MAC address of the ML 100; you should see one after at most a couple of minutes.

# tcpdump -i wlo1 -e -U -XX ether host xx:yy:zz:aa:bb:cc
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlo1, link-type EN10MB (Ethernet), capture size 262144 bytes
07:57:09.757510 xx:yy:zz:aa:bb:cc (oui Unknown) > Broadcast, ethertype ARP (0x0806), length 60: Request who-has 192.168.1.112 tell 192.168.1.112, length 46
    0x0000:  ffff ffff ffff xxyy zzaa bbcc ddee ffgg  ........s.r.....
    0x0010:  hhii jjkk llmm xxyy zzaa bbcc c0a8 0170  ........s.r....p
    0x0020:  0000 0000 0000 c0a8 0170 0000 0000 0000  .........p......
    0x0030:  0000 0000 0000 0000 0000 0000            ............

that [c0a8 0170] at either 0x001c or 0x0026 in the -vv dump is the IP address: c0.a8.01.70 = 192.168.1.112

N.B. MAC is not the same as Mac above.

 

[drbitboy]

Heh, here's a simple one, requires only Window 10 and a command line (Press [Windows] and [R] keys, then type "cmd" and press Enter):

C:\Users\me>for %h in (0 1 2 ) ^
More? do for %i in ( 0 1 2 3 4 5 6 7 8 9 ) ^
More? do for %j in ( 0 1 2 3 4 5 6 7 8 9 ) ^
More? do ping -n 1 -w 10 192.168.1.%h%i%j

N.B. that assumes your local network is 192.168.1.0/24; adjust as needed and ignore any errors.


Wait for that complete, then do

> arp -a

You should see the IP of the ML1100 next to its MAC address.

 

[BachPhi]

Pretty nifty there, to put them in CMD file format:

@ECHO OFF

SET A=0 1 2
SET B=0 1 2 3 4 5 6 7 8 9

FOR %%h IN (%A%) DO (
	FOR %%i IN (%B%) DO (
		FOR %%j IN (%B%) DO (
		PING -n 1 -w 10 192.168.1.%%h%%i%%j
		)
	)
)

ARP -a

 

[drbitboy]

Pretty nifty there, to put them in CMD file format:
...

Nice! Can you make the 192.168.1 into a command-line parameter e.g. so

   aryp.bat


   arpy.bat 192.168.10

and the first command covers netmask 192.168.1.0/24 (which will be the most common, probably); the latter covers netmask 192.168.10.0/24.

 

[BachPhi]

REM Usage: FINDHOST 192.168.1.
::
@ECHO OFF


SET A=0 1 2
SET B=0 1 2 3 4 5 6 7 8 9

FOR %%h IN (%A%) DO (
		FOR %%i IN (%B%) DO (
			FOR %%j IN (%B%) DO (
			PING -n 1 -w 10 %1%%h%%i%%j >> Result.Txt
			)
		)
		
)

ARP -a >> Result.Txt