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Byte order and scale are set per register in the window Register bewerken (Edit register), on the page of the Modbus device. The other fields in that window are described in Set up registers. A wrong setting gives no error message. The Modbus device does answer, but the portal shows a number that is wrong.
What you need
- The role Owner, Admin or Technician in your organisation.
- The register table from the manual of the Modbus device.
- A value that you read on site and that is not 0, such as the voltage on the display.
When the byte order matters
The byte order matters for int32, uint32 and float32. These data types span two registers, and the manufacturer chooses the order of the four bytes. The field Byte-volgorde (Byte order) appears as soon as you choose one of these three in Datatype (Data type). For int16 and uint16 the field is not there, because the Modbus standard fixes the order within a single register.
The table shows what each choice gives for a float32 of 230.5 V that the Modbus device sends as ABCD.
| Byte order | What changes | Result |
|---|---|---|
| ABCD (1,2,3,4) | Nothing | 230.5 V |
| CDAB (3,4,1,2) | The two registers swapped | -2.4 × 10⁻⁴¹ |
| BADC (2,1,4,3) | The bytes in each register swapped | 2.3 × 10²³ |
| DCBA (4,3,2,1) | All four bytes reversed | 1.2 × 10⁻³⁸ |
The portal shows the result of CDAB and DCBA as 0. For a float32, a 0 or an impossibly large number therefore often points to a wrong order.
For int32 and uint32, a wrong order can give a number that is plausible. A counter reading of 1000 becomes 59 395 in BADC, for example. Compare a counter reading digit by digit with the display. How the four orders are named in manuals is explained in the course lesson Word order and floats.
Check the byte order
A value that you read on site shows the right order. Check registers from a template as well. The byte order that a template sets is not always right.
Open the gateway list
Open Gateways in the menu.
Open the gateway
Open the gateway that the Modbus device is connected to.
Open the Modbus device
Under Modbus devices, click the Modbus device. The registers appear in a list with their Type and Laatste waarde (Last value).
Open the register
Click the pencil (Register bewerken) next to a float32, int32 or uint32 register that you can read on site.
Choose the order
In Byte-volgorde, choose the order from the manual. If the manual gives none, choose an order that you have not tried yet.
Save the setting
Click Opslaan (Save). The portal sends the new setting to the gateway.
Compare the value
Compare the Laatste waarde with the display as soon as the next reading arrives. Under the value you can see how old the reading is.
If the value is wrong, choose another order and compare again. Each attempt waits for a new reading, by default every 300 seconds (5 minutes). How to change the polling interval is described in Choose the polling interval. A register that reads 0 gives 0 in every order and therefore shows nothing.
If no order is right, check the address with Enter a register address from the manual. If a 32-bit value is shifted by one address, no byte order helps. Other causes are described in Values are wrong.
If the value jumps between right and nonsense or 0 with the same setting, the byte order is not the cause. A wrong order makes a value wrong every time, not now and then. Look for the cause in the wiring, as described in Answers on RS485 drop out or are garbled.
Set the byte order for all registers
If the Modbus device uses one order for all its 32-bit values, set it in one go.
Open the register
On the page of the Modbus device, click the pencil (Register bewerken) next to a float32, int32 or uint32 register.
Choose the order
In Byte-volgorde, choose the order that you have checked.
Select all registers
Select Toepassen op alle registers van dit Modbus apparaat (Apply to all registers of this Modbus device).
Save the setting
Click Opslaan. The portal reports that the byte order has been applied to all registers.
16-bit registers and registers of other Modbus devices keep their setting. The template does not change. If the wrong order was in a library template, adjust the template as well, as described in Adjust a library template. A Modbus device that you add afterwards then gets the right order.
Set the scale
The portal shows the raw value times Schaal (x) (Scale). If the Modbus device sends 2305 for 230.5 V, the scale is 0.1. If the manual gives a division such as /100, the scale is 0.01. If the Modbus device sends Wh and you want to see kWh, the scale is 0.001 and the unit is kWh.
Open the register
On the page of the Modbus device, click the pencil (Register bewerken) next to the register.
Enter the scale
In Schaal (x), enter the factor from the manual. If the manual gives no factor, enter
1.Save the setting
Click Opslaan. The Laatste waarde shows the scaled value straight away.
The portal stores the raw value and scales it only when it shows it. A new scale therefore also applies to readings that have already arrived, in Trends, on dashboards, in Download readings and in the API. Alert rules and automations compare their limit with the scaled value. After a new scale, check the limits of alert rules and automations on that register as well.
Updated on 7 October 2026
Still stuck?
Email or call us. Include the serial number of the gateway, so we can take a look straight away.
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