Welcome, Craig!
You will find with Ignition there is no ‘one-way’ of doing things, there are multiple ways this can be done.
This is how I do it, note the version is 7.9 so scripts will need slight updates for best performance on 8.1.x
You seem to be concerned with loss to a single device, the following is for an overview of all devices but it might give you some ideas.
I have a tag that counts the total number of connected devices:
import system
cDS = system.dataset.toPyDataSet(deviceDataset)
c=0
for r in cDS:
if r['State']=="Connected":
c = c + 1
system.tag.write("Diagnostics/Devices_Connected", c)
I have an alarm set on this tag saying if below X count and for Y duration then send an email out.
Further to that I have a power table with a ‘refresh’ button with the following script:
deviceDataset = system.device.listDevices()
# Assign the deviceDataset to a Power Table. This example assumes
# the Power Table is in the same container as the component that called this script
event.source.parent.getComponent('Power Table').data = deviceDataset
This allows you to see at a glance what devices are connected/connecting/disconnected/disabled and the driver type, easier than the gateway status page as it is constantly refreshing.
Further to that I have a periodic script that pings each device and records the status to a DB, this then lets me see if there are drops in the diagnostic count which sites were not responding at that time historically;
def ping(address,timeout=2000):
global pingStat
from java.net import InetAddress
ip = InetAddress.getByName(address)
if ip.isReachable(timeout) == True:
pingStat = 1
elif ip.isReachable(timeout) == False:
pingStat = 0
def dev_ping():
dlist = system.device.listDevices()
for row in range(dlist.getRowCount()):
# Check if device uses ModbusTCP driver and device is enabled
if dlist.getValueAt(row,3) == "ModbusTcp" and dlist.getValueAt(row,1) == 1:
# Get device host name.
devSite = dlist.getValueAt(row,0)
print devSite
devIP = system.device.getDeviceHostname(dlist.getValueAt(row,0))
print devIP
ping(devIP)
if pingStat == 1:
print "Dev ok"
system.db.runSFPrepUpdate("insert into ign.dev_stat (dev_site, dev_ip, dev_state) values (?,?,?)",[devSite, devIP, pingStat],datasources=["MySQL"])
elif pingStat == 0:
print "no conn"
system.db.runSFPrepUpdate("insert into ign.dev_stat (dev_site, dev_ip, dev_state) values (?,?,?)",[devSite, devIP, pingStat],datasources=["MySQL"])
dev_ping()
As usual, YMMV.
