Unable to ping on network

I'm facing a strange problem. I was asked to enable a printer on a PLC network, this printer needs to print from a chart recorder attached to some other hardware. I ran a cable, set up the chart recorder to print and it works, that part is successful.

Problem: The chart recorder doesn't print in the format that we need. This is a validated process, and the printout that we are validated for was previously printed by transferring an SD card from the chart recorder to a computer with print software installed off of the network.

I believe that I can do one of the following:

1. Attach a computer with the appropriate software to the network and print the correct format. Or,

2. Attach a computer to the network and print from the web interface built into the chart recorder in the correct format. This is my preferred option if it works.

However, I am unable to navigate to the web interface for the chart recorder on port 80 or 443. I am unable to ping the chart recorder or the printer at the IP addresses that they are successfully printing from.

Why would I be unable to ping or reach the web interface?

That's an interesting challenge and problem, and likely more of an IT/networking issue than the automation devices involved.

Can you specify the make and model of chart recorder and printer you are using ?

>I am unable to ping the chart recorder or the printer at the IP addresses that they are successfully printing from.

Click to expand...

Certainly some devices block PING and HTTP. But printers are usually oriented toward discoverability and troubleshooting instead of security, so it's uncommon.

The first and obvious question is whether the PC you're using to send ICMP PING and HTTP requests is really on the same physical or logical network. Check your subnet mask carefully, and get connected as close to the devices as you can physically get.

Are you using managed switches or routers that might be isolating your PC from those devices with a VLAN or router ?

Check your own PC's ability to use PING and HTTP by connecting a device you know has none of those ports blocked to the network. I often grab a small PLC or an I/O device with physical switches to set the IP address for that kind of test.

There are numerous IP scanning tools on the market. The ones I like the best are free or cheap: NMAP, Angry IP Scanner, and Slitheris Network Discovery. I find that walking into a network I know nothing about, Slitheris tends to poke its nose into features and functions more deeply than the others.

Thanks,

The chart recorder is a Yokogawa GX20.

I plugged into the same network cable that the printer was connected to so it really seems like it should have worked.

Here's some more details: One of the previous maintainers sent me an email that had a list of ARP entries from the server and they are all over the place. some entries are 193.169.2.x, some are 224.0.0.x, I think they were just picking addresses out of a hat and using whatever. The yokogawa is currently on 172.31.0.111, and the printer that works is set to 172.31.0.199. I set the mask to 255.255.255.0 on both devices.

From the ARP table, the HMI's appear to be set to 193.169.2.1 - 193.169.2.201, so I guess that's 255.255.255.0.

There does not seem to be DHCP on this network since when I set my computer to "obtain an IP address automatically" when plugged into the printer cable, I get a link local/non networked address.

Last detail, maybe relevent. My computer automatically sets this network as a public network, so maybe some network ability is turned off? I tried shutting off the windows firewall but there was no change.

Have you tried connect with your PC network card gateway address pointing directly to IP address of printer (172.31.0.111)?

When testing my pylogix I/O adapter, I found that incoming connection packets are ignored when the network is set to public. I always have to switch it back to private.

In powershell:
Set-NetConnectionProfile -Name "Network Name" -NetworkCategory Private

Ugh. Someone powered it off since I was in there yesterday, I didn't check at first because its in a clean room and I needed to don ppe. I turned it on and it now answers ping and I can bring up the web interface.

I did have the ping issue a few weeks back before I tabled this problem to put out other fires. I think setting -NetworkCategory Private fixed it too.

Thank you all for your help.