This guide covers what is needed to install an MBus Splitter, how to mount and wire it, how to set the jumpers, what the LEDs mean and what to check if it does not work.
Before you start
- Cable for the MBus connections: area 0.25 to 1.5 mm², for example standard telephone cable EKKX 2x2x0.5. MBus is a two wire bus with no polarity.
- Every connected meter must have a unique primary address between 1 and 250.
- A 24 V supply is needed when more than one meter is connected, or if the splitter cannot operate the connected meter. Use 24 to 35 VAC or 30 to 40 VDC, and only to power the splitter, not other devices.
Parts of the unit
- Screw terminal MBus OUT1, isolated
- LED MBus OUT1, isolated
- LED MBus IN
- Screw terminal MBus IN
- Configuration jumpers
- Screw terminal external power, optional
- LED MBus OUT2, power
- Screw terminal MBus OUT2, power
Mounting
The splitter mounts on a DIN rail or directly on a wall. For wall mounting, remove the black mounting bracket from the back of the unit and fix it to the wall. Then snap the splitter onto the bracket.
Wiring
- Connect the meters to the terminals marked MBus IN, up to four meters.
- Connect the MBus masters to the terminals marked MBus OUT2 and OUT1. OUT2 must be connected because it provides power to the splitter.
- Connect the external 24 V supply if more than one meter is connected.
Operation
When the splitter is powered up it takes up to 5 minutes before it is ready, because it needs to charge. During charging, all LEDs flash four short flashes in order every three seconds.
- Set the four jumper settings to suit the installation. See Settings below.
- Start the meter installation by changing the position of any jumper, from off to on or from on to off. Then put the jumper back to its original position.
- During scanning, the LED for MBus IN flashes with a short flash every second. Depending on the scanning speed, scanning takes from 1 to 8 minutes.
- When scanning is complete, the splitter is in normal operation. Check the LED indications below.
Settings
The settings are made by setting jumpers on or off. Terminal numbers 1 to 5 refer to the jumpers shown in the picture.
| Jumper | Setting | Jumper on | Jumper off |
|---|---|---|---|
| 1, yellow | Speed MBus OUT1 | 2400 baud | 300 baud |
| 2, blue | Scanning speed MBus IN | 2400 baud | 300 and 2400 baud |
| 5, red | Speed MBus OUT2 | 2400 baud | 300 baud |
Readout interval for MBus IN
Jumpers 3 and 4, black, set how often the meters are read, from 1 minute to 12 hours.
| Jumper 3 | Jumper 4 | Readout interval |
|---|---|---|
| Off | Off | 1 minute |
| Off | On | 5 minutes |
| On | Off | 30 minutes |
| On | On | 12 hours |
LED indications
MBus IN
| What you see | What it means |
|---|---|
| 4 short flashes every 3 seconds | Start up and charging |
| Short flash every second | Readout |
| Off | No meter installed, or an error on the bus |
| 1 flash every 12 seconds | 1 installed meter |
| 2 flashes every 12 seconds | 2 installed meters |
| 3 flashes every 12 seconds | 3 installed meters |
| 4 flashes every 12 seconds | 4 installed meters |
MBus OUT2
| What you see | What it means |
|---|---|
| 4 short flashes every 3 seconds | Start up and charging |
| Off | Error on the bus |
| 1 flash every 12 seconds | Normal operation |
| 2 flashes every 12 seconds | Communication took place in the last minute |
MBus OUT1
| What you see | What it means |
|---|---|
| 4 short flashes every 3 seconds | Start up and charging |
| Off | Error on the bus |
| 1 flash every 12 seconds | Normal operation |
Troubleshooting
Make sure that:
- All cables are connected properly, both on the splitter and on the MBus master.
- The voltage on MBus IN is greater than 23 VDC. If it is lower, disconnect one meter at a time to find the failing meter.
- The voltage on MBus OUT2 is greater than 26 VDC. If it is not within this range, check the function of the MBus master. Connect the external 24 V supply when connecting more than one meter. When low voltage is detected on MBus IN, all LEDs flash four times.
- The connected MBus meters all have unique primary addresses.
- If the fault remains, contact Product and Data Support.
Need a hand on site? Contact Product and Data Support at pds_support@sycous.com.