Values are wrong

A wrong value does not cause an error message in the portal. The Modbus device does respond, but usually a setting of the register does not match how the device sends the value. As the quickest check, put a value from the display next to the Laatste waarde (last value), as described in Check and hand over the installation.

The table links what you see to the likely cause.

What you need

• The role Owner, Admin or Technician to change a register.
• The register map from the manual of the Modbus device.

Change a register

You make every fix below in the Register bewerken (edit register) window.

1. Open the gateway list

   Open Gateways in the menu.

2. Open the gateway

   Open the gateway the Modbus device is connected to.

3. Open the Modbus device

   Under Modbus devices, click the card of the Modbus device. Each register shows the Laatste waarde, with the age of the reading below it.

4. Open the register

   Click the pencil next to the register that is wrong (Register bewerken).

5. Change the field

   Change the field that matches the symptom, such as Byte-volgorde or Schaal (x).

6. Save the change

   Click Opslaan (save). The portal sends the new setting to the gateway.

7. Compare again

   After the next reading, compare the Laatste waarde with the display again.

Value is nonsense or a huge number

The portal shows a number that is not possible, such as a voltage of millions of volts.

The byte order is wrong

For int32, uint32 and float32, the gateway joins two registers in the order set in Byte-volgorde. If that order is wrong, even for a register from a template, choose another one as described in Set the byte order and scale factor.

The address of a 32-bit value is off by one

If Adres is one too high or one too low, the gateway reads half of two values and no byte order helps. Convert the address with Enter a register address from the manual.

A negative value is set as unsigned

With uint16, a value of -5 shows as 65 531 in the portal. If the manual calls the register signed, choose int16, or int32 for a 32-bit register.

The Modbus device reports that there is no reading

Some Modbus devices send 65 535 or -32 768 when there is no reading, such as an inverter that is off at night. If the manual names that value, the setting is correct. The course shows which fixed values are common.

Value is off by a factor of 10, 100 or 1000

The digits are right, but the decimal point is in the wrong place.

The scale is missing or wrong

The portal shows the value read multiplied by Schaal (x). If the portal shows 2314 V where the display says 231.4 V, the scale should be 0.1. If the Modbus device sends Wh and the unit is kWh, the scale is 0.001. After Opslaan, the Laatste waarde changes at once.

Value belongs to another register

The value seems right, but it belongs to another quantity, such as the frequency instead of a voltage.

The address is counted from 1

The portal counts register addresses from 0. If the manual counts from 1, or if only 40000 was subtracted from 40001, the gateway reads the neighbouring register for a 16-bit value. Convert the address with Enter a register address from the manual.

The function belongs to the other type of register

A holding register and an input register with the same address are two different registers. In Functie, choose what the manual names, Read holding registers (3) or Read input registers (4).

Value stays 0

The Laatste waarde is always 0. A current without load is also 0 on the display, so compare a register that is not 0 there.

A float32 has the wrong byte order

With some wrong orders, a float32 becomes so small that the portal shows 0. Choose another order as described in Set the byte order and scale factor.

The data type does not match the register

If a 32-bit register is set as int16 or uint16, the gateway reads only one of the two registers. A counter then stays 0, or starts again at 0 after 65 535.

The gateway reads only int16, uint16, int32, uint32 and float32. It reads every other type in the Datatype list as float32, and then the value is wrong. Choose one of the five as described in Set up registers.

Value is negative but should be positive

The portal shows a negative counter reading or a negative consumption.

The data type is signed but the register is unsigned

An int16 turns negative above 32 767. A counter reading of 40 000 then shows as -25 536 in the portal. Choose uint16 or uint32 if the manual calls the register unsigned.

The current transformer is the wrong way round

If a current transformer of a kWh meter is fitted the wrong way round the cable, the power of that phase is negative at normal consumption. Fit it the other way round, following the manual of the kWh meter.

Current and power are off by a fixed factor

The voltage is right, but current, power and kWh are all too high or too low by the same factor. The display of the kWh meter shows the same error, because the kWh meter calculates with the ratio of the current transformer (CT).

The CT ratio in the kWh meter is wrong

Compare the ratio in the menu of the kWh meter with what is printed on the current transformer, such as 250/5 A. Correct the ratio in the kWh meter and not with Schaal (x), otherwise the display stays wrong. The kWh total counted up to then stays wrong.

Value jumps between good and nonsense

The same bytes with the same settings always give the same result. If a value jumps between good and nonsense or 0 by itself, the cause is not a setting of the register.

The wiring is faulty

Check the wiring of the RS485 bus and the measuring connections of the Modbus device, such as a loose voltage wire on a kWh meter. How to check the bus is described in Answers on RS485 drop out or are garbled.

Contact support

If you cannot solve it, contact us through the support page. Send the serial number of the gateway and the names of the Modbus device and the register. Add the value in the portal and on the display, with a photo of the register map.