User manual

Troubleshooting 35 (46)
Meters are detected but have no data
Some meters may contain a wrong declaration of the secondary address. These meters will be
visible in the meter list but not addressable for meter readouts.
The system parameter MBUS_SELECTMASK makes it possible to mask parts of the secondary
address and replace them with a wildcard character. The version field especially is a frequent
cause of this problem (MBUS_SELECTMASK=4). See Configuration Files, p. 39.
Scanning takes too long
Under certain circumstances, scanning the M-Bus may take an extremely long time (an hour or
more).
1. Try searching for meters gradually by limiting the address space (Primary start address)
or by using a search mask (Secondary address mask).
2. Decrease the system parameter MBUS_MAXRETRY from the default value.
See Configuration Files, p. 39.
Meters that do not respond to a request will then not add excessively to the total scan time.
3. Select a different scan mode, either on the Configuration tab or by setting the system
parameter MBUS_SCANMODE.
Reversed secondary scan (SECONDARYSCANREVERSE) is often particularly useful to
speed up scanning of the M-Bus.
Gateway restarts occasionally during scan
The gateway is equipped with an internal watchdog to prevent denial of service (DoS). If a scan
takes a very long time, the watchdog may reboot the gateway.
Under certain circumstances there can be lots of collisions on the M-Bus, for example if all
meters are responding at the same time. These collisions and the resulting high current draw of
the M-Bus slaves can in exceptional cases trigger a reboot of the gateway.
1. If the scan usually takes a very long time (due to a large number of connected meters or a
slow connection) it may be necessary to increase the value of the system parameter
WATCHDOG_SCAN to prevent the watchdog from rebooting the gateway unnecessarily.
See Configuration Files, p. 39.
2. Try searching for meters gradually by limiting the address space (Primary start address)
or by using a search mask (Secondary address mask).
3. If possible, try to split the bus and scan each bus segment separately.
M-Bus to Modbus-TCP Gateway User Manual SCM-1202-0096-EN 2.1