Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

IP 192.168.0.135 and mask 255.255.254.0 ???

Created by: uel123 at: 1/5/2011 10:50 AM (5 Replies)

Rating (0)

Thanks 2

6 Entries

1/5/2011 10:50 AM	Rate (0)
uel123 Gold Member Joined: 1/29/2006 Last visit: 1/24/2025 Posts: 449 Rating: (65)	Hey, guys! I have a following problem: We are planning to implementa project with 2 CPU-s 1214C and 1 KTP400 panel at one of our customers. Because CPU-s are displaced in different places, we want to establish communication between them through existing factory intranet (Ethernet). Guys from IT department of this company have assigned to us following IP addresses: 192.168.0.135, 192.168.0.136, 192.168.0.137; Subnet mask: 255.255.254.0 Gateway: 192.168.0.1. When we try toset this addresses to our system,we can see, that S7 does not like the combination of 254 (on 3rd octet of subnet mask) and 192 (on1st octet of IP adress). It issues a warning ("Subnet mask is based on different class then the IP address"). S7 wants to tell us, that we should use IP addr. for class B (ends with 191 in 1st octet) instead of class C (beginns with 192 in 1st octet). For now, we are still testing our system at home, with completely separated ethernet (only 2 CPU-s, panel + PG), with proposed IP adresses and Subnet mask for class C (255.255.255.0). At the moment, I do not know, what to do, when we will install this at end customer.... Any ideas??? Sincerely yours! uel123

Suggestion To thank Quote Answer

1/5/2011 11:01 AM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	Hello, Look at What is the connection between subnet masks and IP addresses in the IP address area, also with regard to subnetting? IT department should change the SM. Best regards, Hristo Mihalev

Suggestion To thank Quote Answer

1/5/2011 2:44 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 1/24/2025 Posts: 15558 Rating: (2468)	To me, it looks like your I.T. dept has combined 192.168.0.x and 192.168.1.x to have them all able to communicate without a router/gateway. If you need to communicate with something on 192.168.1.x, you will need that SM of 255.255.254.0 to do that. I did something similar on my home network to keep things easier to manage. If your PLC will compile, load, and run with the 255.255.254.0, then go again. Otherwise, you might need to set it to 255.255.255.0 and have problems communicating with 192.168.1.x devices. The link provided in the priorreply does not seem to offer useful information on your issue.
	science guy
Suggestion To thank Quote Answer

1/5/2011 3:00 PM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	Yes, agree with you. Just confirm uel123' opinion and trials. Also is true that that FAQ regards only S7-300 and S7-400 PLC. For me is need it to change SM concerning PLC. I said it before. Best regards, Hristo Mihalev
	Last edited by: UMENCHO at: 1/5/2011 3:05 PM
Suggestion To thank Quote Answer

1/5/2011 3:04 PM	Rate (0)
uel123 Gold Member Joined: 1/29/2006 Last visit: 1/24/2025 Posts: 449 Rating: (65)	Hello, Hristo! Thank you very much for your answer. According to description in your posted link, obviously our end customer uses "Supernetting" in their internal net. In the mean time, we have tested our configuration locally, with settings of IP addresses and mask, as in customers wish. It seems to work, in stand alone net, allthough "CIDR" functionallity is not explicitly mentioned for 1200 CPUs. It works also with PG connected through our internal ethernet, with totally different IP Address (192.168.2.10, but with mask 255.255.252.0 (on PG!), which extends host area for 2 bits...). At the next step, we will goto end customerand test, what will happen. If any luck, I will post results here. Sincerely yours! uel123

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users umencho

1/27/2011 2:35 PM	Rate (0)
uel123 Gold Member Joined: 1/29/2006 Last visit: 1/24/2025 Posts: 449 Rating: (65)	.... just to confirm: System works OK also with those IP addreses and 255.255.254.0 mask...... TX to all! uel123.

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users umencho

|

Share this page:

Share this page on...

Follow us on