CPU I/O High Load when using Modbus RTU

[jmir]

Hi,

We've a LM which communicates with 8 modbus 485, there are any scripts running and nothing... 

When RTU is enabled CPU/IO rises to 2 or 3 most of the time... Is it normal?

Firmware: 20230612
RTU 2 - 19200 - N/8/1 - HalfDuplex
8 slaves (4 wiith poll time 5s and 4 every 10s)

Thanks.

[Daniel]

How many registers per device and do you use Value send Delta to limit the traffic?

[jmir]

About 20 registers on each slave and I use value delta.

Profiles have more than 20 registers but most of them are not mapped to KNX (devices are input/output modules and I've generic profiles and i'm mapping only what I need)

I've noticed

[Daniel]

install System load app and see what it says. What about KNX traffic?

[jmir]

Hi,

There isn't KNX traffic, there isn't KNX TP line and KNX IP is not used (KNX connection set to IP Routing)

System Load (in this conditions CPU I/O is over 1):

1101
nginx:worker process
0.79%
3.61MB
1077
lua/lib/genohm-scada/plugins/modbus/daemon.lua 1
0.20%
2.43MB
1
/sbin/init
0.00%
0.61MB
714
/sbin/syslogd-C16
0.00%
0.63MB
716
/sbin/klogd
0.00%
0.65MB
718
/sbin/hotplug2--override --persistent --set-rules-file /etc/hotplug2.rules --set-coldplug-cmd /sbin/udevtrigger --max-children 1
0.00%
0.66MB
912
/sbin/watchdog-t 5 /dev/watchdog
0.00%
0.60MB
979
/usr/sbin/gpiod-l /lib/restore/defaults.sh -d /lib/restore/restore.sh -b 9
0.00%
0.29MB
988
/usr/sbin/ntpd-n -p 0.europe.pool.ntp.org -p 1.europe.pool.ntp.org -p 2.europe.pool.ntp.org -p 3.europe.pool.ntp.org
0.00%
0.67MB
997
/usr/sbin/redis-server/etc/redis.conf
0.00%
1.16MB
1058
lua/lib/genohm-scada/core/groupmonitor.lua
0.00%
2.20MB
1069
lua/lib/genohm-scada/core/scenes.lua
0.00%
2.05MB
1070
lua/lib/genohm-scada/core/ipblocker.lua
0.00%
0.93MB
1072
/usr/bin/eibd-e 15.15.255 -q 100 -L 1 -Q 0 -T -f eth0 -D -S224.0.23.12 -F n,n,n,n,0,0 ip:224.0.23.12
0.00%
0.98MB
1076
lua/lib/genohm-scada/plugins/modbus/daemon.lua 0
0.00%
2.28MB
1087
lua/lib/apps/daemon.lua lmcloud /home/apps/store/daemon/lmcloud/daemon.lua
0.00%
2.18MB
1099
nginx:master process nginx -c /tmp/nginx.conf
0.00%
1.02MB
1107
/usr/sbin/crond-l 20 -c /etc/crontabs
0.00%
0.55MB
1113
/usr/bin/dbus-daemon--system
0.00%
0.84MB
1125
/usr/sbin/vsftpd/tmp/vsftpd.conf
0.00%
0.63MB
1137
avahi-daemon:running [LM.local]
0.00%
1.05MB

system
0.00%


total
0.99%
26.02MB

[admin]

The actual CPU usage is low. IO load is high because the Modbus mapper is constantly waiting on data from RS485. This is normal.

[jmir]

The actual CPU usage is low. IO load is high because the Modbus mapper is constantly waiting on data from RS485. This is normal.

Ok, thanks!