Values arrive less often than set

At the bottom of each card on the Overview tab, the portal shows how long ago the Modbus device was last read. If that time grows to a few minutes while the polling interval is a few seconds, the gateway reads less often than set. First check which connection the gateway sends over.

What you need

• The role Owner, Admin or Technician to open Gateway settings.

Live values refresh more slowly than the polling interval

The card on Overview shows each new reading as soon as it arrives.

The gateway sends over the SIM

Open the gateway and click the pencil at the top right (Gateway settings). Under Uitlezen via de SIM (reading via the SIM), Verstuurt nu via (currently sending via) shows whether the gateway sends over Kabel (cable) or SIM, and since when.

On the SIM the gateway never reads faster than the SIM interval, 300 seconds (5 minutes) by default. A Modbus device with a longer polling interval keeps its own interval. The SIM interval is one of the Gateway settings and applies to all Modbus devices on the gateway.

If the gateway works on 4G only, lower the SIM interval. The gateway never reads faster than every 60 seconds on 4G. The steps are in Choose the polling interval. Over a network cable in the WAN port, the gateway reads each Modbus device at its own polling interval, from 1 second.

The network cable does not give internet

If Verstuurt nu via shows SIM while a network cable is plugged in, the gateway gets no internet over that cable. The gateway sends over the cable only if it gives internet. Otherwise the SIM takes over, as described in 4G and the backup SIM.

1. Check the port

   Check that the network cable is in the WAN port. How to connect it is described in Connect to the network via WAN and LAN.

2. Have the network checked

   Ask the IT department to go through the Network requirements for the gateway. The WAN port gets its address over DHCP, and the gateway tests with ping whether the cable has internet.

3. Look at the connection again

   Reload the Gateway settings page. If the cable gives internet, Verstuurt nu via shows Kabel again. The gateway checks every 30 seconds which connection has internet and switches back by itself.

The gateway runs older software

Verstuurt nu via shows Onbekend (unknown), and below it the portal says that the gateway still runs older software. Such a gateway reads no faster than every 60 seconds, even over the cable. If you want faster reading, contact support.

A polling round takes longer than the interval

A round overruns with a short interval and many registers, or when a Modbus device on the RS485 bus does not answer. After at least 15 minutes without a reading, such a Modbus device shows Timeout on Overview. If it has never answered, the card shows No data received yet.

The gateway asks one question per register, and all Modbus RTU devices on a gateway share one bus. If a Modbus device does not answer, the gateway waits up to 1 second per register, every round again. The other Modbus devices on the bus then get their turn later.

How to make a Modbus device answer again is described in Modbus device shows no values. If the bus has many registers, raise the polling interval. To work out how long a round takes, use the lesson Calculate your poll interval and bus load.

Values drop out now and then

The time at the bottom of the card on Overview then occasionally rises far above the polling interval and drops back later.

The 4G reception is weak

Weak reception only matters if Verstuurt nu via shows SIM. The portal does not show the strength of the 4G signal. Check on site where the antenna is.

A metal cabinet blocks the 4G signal. Place the antenna outside the cabinet. If the connection drops for so long that the gateway switches to Offline, follow Gateway is offline.

Automatic search or control pauses reading

During automatic search, reading of all Modbus devices on the gateway stops. Searching is usually done within 2 minutes. A write command through Control to a Modbus RTU device pauses reading until the command is done. After that, reading continues by itself.

The chart shows fewer readings than the gateway reads

On Trends and in the file from Download readings, there is at most one reading per minute, even if the live values change every second.

The history stores one reading per minute

Live values, alerts and automations get every reading. For each register, the history stores the first reading of every minute, and charts and Download readings read the history. From the period 24h, the chart also shows averages.

A polling interval under 60 seconds therefore does not make the history finer. What a point in the chart stands for per period is described in View values and charts.

Contact support

If this does not solve it, contact us through the support page. Send the serial number of the gateway, what Verstuurt nu via shows, the polling interval you set and how often the values actually arrive.