2. Installation
2.1. Overview of connections
On the Cerbo-S GX, the USB socket closest to the HDMI connector can only be used to power a GX Touch. That USB port can not be used for any data related functions such as VE.Direct to USB cables, USB-sticks, USB-GPS-es, or other common USB usages. It’s a power port only, no data.
2.2. Power
The device is powered by using the Power in V+ connector. It accepts 8 to 70 V DC. The device will not power itself from any of the other connections (eg network). The supplied DC power cable includes an inline 3.15 A slow blow fuse.
When the Cerbo-S GX is used in an installation with a VE.Bus BMS, connect the Power in V+ on the Cerbo-S GX to the terminal labelled 'Load disconnect' on the VE.Bus BMS. Connect both negative leads to the negative stub of a common Battery.
A Cautionary word about Powering from the AC-out terminal of a VE.Bus Inverter, Multi or Quattro:
If you power the Cerbo-S GX from an AC adaptor connected to the AC-out port of any VE.Bus product (Inverter, Multi or Quattro), then a deadlock will occur after the VE.Bus products are powered-down for any reason (after any operational fault or during a black start). The VE.Bus devices will not boot-up until the Cerbo-S GX has power …but the Cerbo-S GX will not boot-up until it has power. This deadlock can be rectified by briefly unplugging the Cerbo-S GX VE.Bus cable at which point you will observe the VE.Bus products will immediately begin to boot-up.
Or a modification can be done to the RJ45 cabling. See FAQ Q20 for more information about this.
Note that both with or without above modification, powering the monitoring equipment with the AC-out of an inverter/charger (ofcourse) has the disadvantage that all monitoring is shut down when there is a problem that causes the inverter/charger to shut down. Examples are Inverter overload, high temperature or low battery voltage. It is therefore recommended to power the GX device from the battery.
Isolation
Because the Cerbo-S GX is connected to many different products, please ensure that proper care is taken with isolation to prevent ground loops. In 99% of installations this will not be a problem.
The VE.Bus ports are isolated
The VE.Direct ports are isolated
The USB ports are not isolated. Connecting a Wi-Fi Dongle or GPS Dongle will not create a problem as it is not connected to another power supply. Even though there will be ground loop when you mount a separately-powered USB hub, during extensive testing we have not found that it caused any issues.
The Ethernet port is isolated, except for the shield: use unshielded UTP cables for the Ethernet network
Extending USB ports by use of a self-powered USB hub
Although the number of USB ports can be extended by using a hub, there is a limit to the amount of power that the onboard USB port can provide. When extending the number of USB ports, we recommend you always use powered USB hubs. And to minimize the chance of issues, be sure to use good-quality USB hubs. As Victron also offers a VE.Direct to USB adapter, you can use this arrangement to increase the number of VE.Direct devices you can connect to your system, please see this document for the limit of how many devices can be attached to various different GX devices.
2.3. Mounting options and accessories
2.4. Connecting Victron products
2.4.1. Multis/Quattros/Inverters (VE.Bus products)
In order to keep this document short we are going to refer to all Multis, Quattros and Inverters as VE.Bus products.
The earliest version of the VE.Bus devices which can be connected to the Cerbo-S GX is 19xx111 or 20xx111, which were released in 2007. VE.Bus firmware 26xxxxx and 27xxxxx are also supported …but 18xxxxx is not.
Note that for Multis, Quattros and EasySolars, it is not possible to use the Remote On/Off (header on the VE.Bus control PCB) in combination with a Cerbo-S GX. There should be wire between the left and middle terminal, as it is when shipped from the factory. In case a wired switch that disables the system is required, use the Safety Switch Assistant instead.
This limitation does not apply to the next generation of VE.Bus inverter/chargers: when using a MultiPlus-II, Quattro-II or EasySolar-II, the Remote on/off terminal header *can* be used in combination with Cerbo-S GX.
Single VE.Bus products
To connect a single VE.Bus product, connect it to one of the VE.Bus sockets on the back of the Cerbo-S GX. Both sockets are identical, use either one. Use a standard RJ45 UTP cable, see our pricelist.
Parallel, split- and three-phase VE.Bus systems
To connect multiple VE.Bus products, configured as a parallel, split-phase or three phase VE.Bus system, connect either the first or the last VE.Bus product in the chain to either one of the VE.Bus sockets on the back of the Cerbo-S GX. Use a standard RJ45 UTP cable, see our pricelist.
VE.Bus systems with Lithium batteries and a VE.Bus BMS
Connect the Cerbo-S GX to the socket labelled ‘MultiPlus/Quattro’, or to one of the Multis/Quattros in the system. Do not connect it to the Remote panel socket on the VE.Bus BMS.
Note that it will not be possible to control the On/Off/Charger Only switch. This option is automatically disabled in the Cerbo-S GX menu when a VE.Bus BMS is used. The only way to control a Multi or Quattro when used with a VE.Bus BMS is to add a Digital Multi Control to the system. Setting the input current limit is possible in systems with a VE.Bus BMS.
Combining MultiPlus/Quattro with a VE.Bus BMS and a Digital Multi Control is possible. Simply connect the Digital Multi Control to the RJ-45 socket on the VE.Bus BMS labelled Remote panel.
To allow auto-power-down in the Cerbo-S GX in case of a low battery, make sure the Cerbo-S GX is powered via the VE.Bus BMS: connect Power in V+ on the Cerbo-S GX to Load disconnect on the VE.Bus BMS. And connect both negative leads to the negative stub of a common Battery.
Combining the Cerbo-S GX with a Digital Multi Control
It is possible to connect both a Cerbo-S GX and a Digital Multi control to a VE.Bus system. The ability to switch the product On, Off or set it to Charger Only via the Cerbo-S GX will be disabled. The same applies to the input current limit: when there is a Digital Multi Control in the system, the input current limit which is set at that control panel will be the master-setting, and changing it on the Cerbo-S GX will not be possible.
Connecting multiple VE.Bus systems to a single Cerbo-S GX
Only one VE.Bus system can be connected to the VE.Bus ports on the back of the Cerbo-S GX. The professional way to to monitor more systems is to add a second Cerbo-S GX
If you do require to connect more than one system to the same Cerbo-S GX, use an MK3-USB. Functionality will be limited:
Only the system connected to the built-in VE.Bus ports is used to generate the data on the Overview pages.
All connected systems will be visible on the Device-list
All connected systems will be taken into account for Energy consumption and distribution calculations (kWh graphs on VRM)
Only the system connected to the built-in VE.Bus ports is used for the Generator start/stop logic
In case of an ESS system, only the system connected to the built-in VE.Bus ports is used in the ESS mechanisms. The other one is displayed in the device list only.
Alternatively the VE.Bus to VE.Can interface (ASS030520105) can be used. Add one for each additional system. Note that we advise against it; this interface is a deprecated product. Make sure that the VE.Can network is terminated and powered. For powering the VE.Can network, see Q17 in our data communication whitepaper.
Additional features provided by a GX device to VE.Bus products
An internet connected GX device allows for remote configuration via the VRM Portal. Please read the Remote VE.Configure manual for more information, system requirements and specific steps to access this feature.
2.4.2. Battery Monitor SmartShunt, BMV-700 series; and MPPTs with a VE.Direct port
Direct connection via a VE.Direct cable is limited to the number of VE.Direct ports on the device (see Overview of Connections). There are two types of VE.Direct cable available:
Straight VE.Direct cables, ASS030530xxx
VE.Direct cables with an angled connector on one end. These are designed to minimize the required depth behind a panel, ASS030531xxx
VE.Direct cables have a maximum length of 10 metres. It is not possible to extend them. If longer lengths are required, use a VE.Direct to USB adapter with an active USB extension cable.
It is also possible to use the VE.Direct to VE.Can interface, but note that this only works for BMV-700 and BMV-702. Not for the BMV-712, MPPT solar chargers and Inverters with a VE.Direct port. See next paragraph for more information on that VE.Can interface.
Connecting more VE.Direct devices to your Cerbo-S GX than number of VE.Direct Ports
First of all, note that the maximum of VE.Direct devices that can be connected is GX device specific, and constrained by the CPU power. It may also be reduced for very complex systems, such as many AC PV inverters or synchronised inverter chargers, etc. So always allow some additional headroom in the design. How they are connected, so direct, via USB or hub does not change this maximum. See here for the maximum limit on all GX devices Devices.
Then, these are the options on how to connect more VE.Direct products than available VE.Direct ports:
Option 1: Use the VE.Direct to USB interface. The Cerbo-S GX has built-in USB ports (see Overview of Connections). Use a USB-hub when additional USB ports are required.
Option 2: (Only!) the BMV-700 and BMV-702 can also be connected using the VE.Direct to VE.Can interface. Note that the BMV-712, MPPTs and VE.Direct Inverters cannot be connected using this CAN-bus interface as it does not translate their data into CAN-bus messages. When using the VE.Direct to VE.Can interface, make sure that the VE.Can network is terminated, and also powered. For powering the VE.Can network, see Q17 in our data communication whitepaper. Lastly, note that this CAN-bus interface is deprecated.
DC Load Monitor Mode
If you wish to use a SmartShunt or BMV-712 to monitor individual DC circuits, rather than as a whole-of-system battery monitor you can change the Monitor mode setting from Battery Monitor to DC Energy Meter in VictronConnect.
If DC meter is selected, you can the select the following types (also in VictronConnect);
Solar charger, Wind charger, Shaft generator, Alternator, Fuel cell, Water generator, DC/DC charger, AC charger, Generic source, Generic load, Electric drive, Fridge, Water pump, Bilge pump, DC system, Inverter, Water heater
Once connected to a GX device, the type, and the amps and power of the DC load is shown in the user interfaces and available on the VRM Portal.
When configured as type “DC System”, the GX does more than just recording and visualisation:
the power shown in the DC system box is the sum of power reported by all SmartShunts configured as such. Allowing multiple meters is done to accommodate for example a catamaran, so you can measure the DC Systems on Port hull and on Starboard hull.
the DC System Current is being compensated for when setting DVCC charge current limits to Multis, Quattros and Solar Chargers. For example when a load of 50A is being measured, and CCL by the battery is 25A, the limit given to the Multis & Solar Chargers is 75A. An improvement for systems with significant DC loads such as Yachts, Coaches and RVs.
Notes and limitations: (A) this feature is available for SmartShunts and BMV-712. Not for BMV-700 or BMV-702.
(B) Setting the meter mode is done with VictronConnect, in the BMV/SmartShunt itself.
(C) The NMEA2000-out feature does not support these new types, for example when using a SmartShunt to measure output of an alternator, that data is not made available on NMEA2000.
Notes about older VE.Direct MPPTs
An MPPT 70/15 needs to be from year/week 1308 or later. Earlier 70/15s are not compatible with the Cerbo-S GX , and unfortunately upgrading the MPPT firmware will not help. To find the year/week number of your model, look for the serial number which is printed on a label on its back. For example number HQ1309DER4F means 2013, week 09.
2.4.3. VE.Can Devices
To connect a product with a VE.Can port, use a standard RJ45 UTP cable (available with straight and elbow connectors).
Don't forget to terminate the VE.Can network at both ends using a VE.Can terminator. A bag with two terminators is supplied with each VE.Can product. They are also available separately.
Other notes:
In order to work with the Cerbo-S GX an MPPT 150/70 needs run firmware v2.00 or newer.
You can combine a Skylla-i control panel with a Cerbo-S GX.
You can combine a Ion Control panel with a Cerbo-S GX.
All VE.Can devices power the VE.Can network, so it won't be necessary to power the VE.Can network separately in these circumstances. All the protocol converters, for example the VE.Bus to VE.Can interface; and the BMV to VE.Can interface, do not power the VE.Can network.
The following products also support VictronConnect-Remote monitoring and configuration:
Lynx Shunt VE.Can and Lynx Smart BMS
Multi RS, Inverter RS and MPPT RS
Skylla-i and Skylla-IP44/-IP65 (requires firmware v1.11)
all VE.Can solar chargers except the very old (big rectangular case with display) BlueSolar MPPT VE.Can 150/70 and 150/85
2.4.4. VE.Can and BMS-Can Interfaces
By default; VE.Can is set to 250 kbit/s & BMS-Can (if present) is set to 500 kbit/s
VE.Can is intended to be used for the Victron (and Victron compatible) VE.Can products, such as the VE.Can MPPTs, and VE.Can Lynx Shunt. You can string these VE.Can 250 kbit/s devices together along this bus. It must be terminated at both ends with the included VE.Can terminators.
You CAN set the VE.Can port from 250 kbit/s to be 500 kbit/s (or one of several other CANbus speeds for other CANbus applications).
Other types of Batteries and BMS may claim compatibility with BMS-Can, or VE.Can, but if they are not on the battery compatibility list then they have not been tested and confirmed to work by Victron.
One extra element of possible confusion is that there ARE some BMS products on the market that use a CANbus BMS profile at 250 kbit/s.
These can only be connected to the VE.Can port, and it must also be set to match this (VE.Can & CAN-bus BMS (250 kbit/s)) in the services menu for the VE.Can port.
These BMS can be used in the same cable daisy chain as other Victron VE.Can devices.
2.4.5. Inverter RS, Multi RS and MPPT RS
The Inverter RS, Inverter RS Solar and Multi RS have both VE.Direct and VE.Can interfaces. For these specific products, it is only possible to connect a GX device via the VE.Can interface, and it is not possible to connect a GX device via the VE.direct interface.
The VE.Direct interface on these specific products is only used for connection of a VE.Direct to USB adapter for programming.
This restriction does not apply to the MPPT RS, which can be connected to a GX device via either VE.Direct or VE.Can.
2.4.6. BMV-600 series
Connect the BMV-600 using the VE.Direct to BMV-60xS cable. (ASS0305322xx)
2.4.7. DC Link box
Connect the DC Link box, using the RJ-12 cable supplied. Then connect the BMV-700 to the Cerbo-S GX - see connecting BMV-700 for more instructions.
2.4.8. VE.Can Resistive Tank Sender Adapter
See its page and manual on our website for details about the Adapter.
To connect a product with a VE.Can port, use a standard RJ45 UTP cable.
Don't forget to terminate the VE.Can network on both ends using a VE.Can terminator. A bag with two terminators is supplied with each VE.Can product. They are also available separately (ASS030700000). (Available with straight or elbow connectors.)
Make sure that the CAN-bus is powered, see the Power chapter in the Tank Sender Adapter manual for details.
2.5. Connecting a PV Inverter
Measuring the output of a PV Inverter will provide the user with an overview of both actual power balance and the energy distribution. Note that these measurements are only used to display information. They are not needed, nor used, by the installation for its performance. Besides monitoring, the GX device can also curtail some types and brands of PV Inverters, ie. reduce their output power. This is used, and required, for the ESS Zero or limited feed-in feature.
Direct connections
Type | Zero feed-in | Details |
|---|---|---|
Fronius | Yes | LAN Connection, see GX - GX - Fronius manual |
SMA | No | LAN Connection, see GX - GX - SMA manual |
SolarEdge | No | LAN Connection, see GX - SolarEdge manual |
ABB | Yes | LAN Connection, see GX - ABB manual |
Using a meter For PV Inverters that cannot be interfaced digitally, a meter can be used:
Type | Zero feed-in | Details |
|---|---|---|
No | Connected to inverter/charger analog input. Lowest cost - least accurate. Energy Meter | |
No | Wired to the Cerbo-S GX, or connected wirelessly using our Zigbee to USB/RS485 interfaces. See the Energy Meters start page | |
Wireless AC sensors | No | See the Wireless AC Sensor manual - Discontinued |
2.6. Connecting a USB GPS
Use a GPS to remotely, on the VRM Portal, track vehicles or boats. Also its possible to configure a Geofence, which will automatically send an alarm when the system leaves a designated area. And gps-tracks.kml files can be downloaded, to for example open in Navlink and Google Earth.
Victron does not sell USB-GPS, but the Cerbo-S GX will support third-party GPS modules which use the NMEA0183 command-set - almost all do. It can communicate at both 4800 and 38400 baud rates. Plug the unit into either of the two USB sockets …connection may take a few minutes, but the Cerbo-S GX will automatically recognize the GPS. The unit's location will automatically be sent to the VRM online portal and its position shown on the map.
The Cerbo-S GX has been tested for compatibility with:
Globalsat BU353-W SiRF STAR III 4800 baud
Globalsat ND100 SiRF STAR III 38400 baud
Globalsat BU353S4 SiRF STAR IV 4800 baud
Globalsat MR350 + BR305US SiRF STAR III 4800 baud
2.7. Connecting a NMEA 2000 GPS
Use a GPS to remotely, on the VRM Portal, track vehicles or boats. Also its possible to configure a Geofence, which will automatically send an alarm when the system leaves a designated area. And gps-tracks.kml files can be downloaded, to for example open in Navlink and Google Earth.
The third party NMEA 2000 GPS sender must meet the following requirements:
The NMEA 2000 device class must be 60, Navigation.
The NMEA 2000 device function must be 145, Ownship Position (GNSS).
Position (latitude, longtitude) must be transmitted in either PGN 129.025.
Height, which is optional, must be transmitted in PGN 129.029.
Course and speed (both optional), must be transmitted in PGN 129.026
Most NMEA 2000 GPS-es are expected to work. Compatibility has been tested with:
Garmin GPS 19X NMEA 2000
To connect a NMEA 2000 network to the VE.Can port on the GX device, which both have a different style connector, there are two solutions:
The VE.Can to NMEA2000 cable. Which by either inserting or leaving out the fuse allows to either power the NMEA2000 network with Victron equipment, or not. Take note of below warning.
The 3802 VE.Can Adapter by OSUKL. Its advantage is that it lends itself well to connecting a single NMEA-2000 device such as a tank sender into a VE.Can network. It's also able to power a lower voltage NMEA-2000 network directly from a 48V Victron system.
Warning and solution for 24V and 48V systems
Whilst all Victron components accept up to 70V input on their CAN-bus connections, some NMEA 2000 equipment does not. They require a 12V powered NMEA 2000 connection, and sometimes work up to 30 or 36V. Make sure to check the datasheet of all used NMEA 2000 equipment. In case the system contains NMEA 2000 that requires a network voltage below the battery voltage, then either see above 3802 VE.Can Adapter by OSUKL. Or alternatively install the VE.Can to NMEA 2000 cable without it’s fuse, and provide suitable power to the NMEA 2000 network using for example a NMEA 2000 power adapter cable – which is not supplied by Victron. The VE.Can port on the GX Device does not need external power to operate.
2.8. Connecting a Fischer Panda Generator
2.9. Connecting a GX Tank 140
The GX Tank 140 is an accessory for our range of GX system monitoring products.
It takes readings from up to four tank level sensors.
Tank levels can be read-out locally in the system, as well remotely through our VRM Portal.
The GX Tank 140 is compatible with current senders (4 to 20 mA) as well as voltage senders (0 to 10 V). The connection to the GX Device is via USB, which is also how the GX Tank is powered: no additional power wires required.
To make wiring the tank sender as simple as possible, two of the four inputs provide a 24 V power supply, to power the sender. Using the other two channels requires an external power supply, and there is a power in terminal together with fused outputs to facilitate that.
Upper and lower limits are configurable, to allow using senders that provide only part of the scale, for example 0 to 5 V.
For marine applications, the GX Device can transmit these tank levels on the NMEA 2000 network to be picked up by other displays such as an MFD.
The GX Tank 140 product page links to the complete documentation of this product.
2.10. Connecting third-party NMEA 2000 tank senders
A third party NMEA 2000 tank sender must meet the following requirements to be visible on the GX Device:
Transmit the NMEA 2000 Fluid Level PGN, 127505
The NMEA 2000 device class needs to either General (80) in combination with function code Transducer (190), or Sensor (170). Or, the NMEA 2000 device class needs to be Sensors (75), in combination with function Fluid Level (150).
A single function reporting multiple Fluid Levels is currently not supported.
For some tank senders it is also possible to configure the capacity and the fluid type on the GX Device menus - for example the Maretron TLA100. This facility may be available with other senders made by other manufacturers - it's well-worth trying.
Tested compatible NMEA2000 tank senders:
Maretron TLA100
Maretron TLM100
Navico Fluid Level Sensor Fuel-0 PK, partno. 000-11518-001. Note that you need a Navico display to configure the Capacity, Fluid type, and other parameters of the sensor. See voltage warning below.
Oceanic Systems (UK) Ltd (OSUKL) - 3271 Volumetric Tank Sender. In case it doesn’t work, it needs a firmware update. Contact OSUKL for that. See voltage warning below.
Oceanic Systems UK Ltd (OSUKL) - 3281 Water Level Sender. See voltage warning below
Most likely others work as well. If you know of one working well, please edit this page -or- get in touch with us on Community -> Modifications.
To connect an NMEA2000 network to the VE.Can port on the GX device, which both have different type connectors, there are two solutions:
The VE.Can to NMEA2000 cable. Which by either inserting or leaving out the fuse allows to either power the NMEA2000 network with Victron equipment, or not. Take note of below warning.
The 3802 VE.Can Adapter by OSUKL. Its advantage is that it lends itself well to connecting a single NMEA-2000 device such as a tank sender into a VE.Can network. It's also able to power a lower voltage NMEA-2000 network directly from a 48V Victron system.
Warning and solution for 24V and 48V systems
Whilst all Victron components accept up to 70V input on their CAN-bus connections, some NMEA2000 equipment does not. They require a 12V powered NMEA2000 connection, and sometimes work up to 30 or 36V. Make sure to check the datasheet of all used NMEA2000 equipment. In case the system contains NMEA2000 that requires a network voltage below the battery voltage, then either see above 3802 VE.Can Adapter by OSUKL. Or alternatively install the VE.Can to NMEA2000 cable without it’s fuse, and provide suitable power to the NMEA2000 network using for example a NMEA-2000 power adapter cable – which is not supplied by Victron. The VE.Can port on the GX Device does not need external power to operate.
2.11. Connecting Temperature Sensors
2.11.1. Wireless bluetooth Ruuvi sensors
The Ruuvi sensor features temperature, humidity and atmospheric pressure streamed wirelessly to the GX device.
USB Bluetooth adapters that have been tested and known to work:
Insignia (NS-PCY5BMA2)
Logilink BT0037
TP-Link UB400(UN)
Ewent EW1085R4
Laird BT820
Laird BT851
Kinivo BTD-400
Ideapro USB bluetooth adapter 4.0
A list of additional adapters that are also being tested, as well as adapters that have been tested and are known not to work, is available here: https://community.victronenergy.com/questions/112834/connect-ruuvi-to-ccgx.html
Installation procedure
Make sure that Bluetooth is enabled in the bluetooth menu (enabled by default)
Go to Settings → I/O → Bluetooth sensors menu, then Enable to enable bluetooth temperature sensors.
The Ruuvi sensors come supplied with a removable plastic pull tab. This prevents it from discharging while on the shelf. Pull out the plastic tab and the unit will start transmitting its temperature information.
The sensor should appear in the menu, "Ruuvi ####" - with a 4 hexidecimal device ID, enable the specific Ruuvi sensor.
The Bluetooth adapters submenu displays a list of available Bluetooth adapters. The menu option Continuous scanning permanently scans for new Bluetooth sensors.
If you have multiple sensors, you may wish to physically write this device ID on the sensor case itself to help keep track.
The sensor should now be visible in the main menu - by default is labelled 'Generic temperature sensor (##)'
It is possible inside the temperature sensor menu to adjust the type, and also to set a custom name.
The Ruuvi sensors are estimated to last more than 12 months on a single replaceable CR2477 3V Li coin battery. Both the internal battery voltage and the battery status are displayed in the menu of the respective sensor. Status 'Ok' = battery voltage ≤2.50V. Status 'Sensor battery low' = battery voltage ≥2.50V.
It is possible to update the firmware for the Ruuvi with Ruuvi's own separate phone app, though this is not necessary unless you are experiencing issues.
2.12. Connecting IMT Solar Irradiance, Temperature and Wind Speed Sensors
Compatibility
Ingenieurbüro Mencke & Tegtmeyer GmbH (IMT) offer a range of digital silicon irradiance sensor models within the Si-RS485 series that are all compatible with a Victron GX device.
The optional/additional external module temperature, ambient temperature and wind speed sensors are also supported.
Optional/additional external sensors are either connected to the solar irradiance sensor with pre-installed plugs or pre-wired to the solar irradiance sensor (external module and ambient temperature only). When external sensors are connected via an appropriate solar irradiance sensor, all measurement data is transmitted to the Victron GX device with the single interface cable.
Each model solar irradiance sensor within Si-RS485 series has a different capability with regards to external sensors (or comes with an external sensor pre-wired), so carefully consider any future desires/requirements before initial purchase.
It is also possible to connect an independent IMT Tm-RS485-MB module temperature sensor (visible as ‘cell temperature’) or IMT Ta-ext-RS485-MB ambient temperature sensor (visible as ‘external temperature’) directly to the Victron GX device, without a solar irradiance sensor or in addition to one.
Operation
The IMT Si-RS485 series solar irradiance sensors operate using RS485 electrical interface and Modbus RTU communication protocol.
The Victron GX device must be running version 2.40 or later.
The IMT sensor needs to be firmware version 1.52 minimum - for more information about this please contact IMT.
Physical connection to the Victron GX device is via USB port and requires a Victron RS485 to USB interface cable.
A suitable external DC power source (12 to 28 VDC) is also required - the sensor is NOT powered via USB.
Wiring Connections
The schematic in the installation guide below depicts the wiring configuration in a typical installation.
Wire connections
Si-Sensor | Victron RS485 to USB interface | Signal |
|---|---|---|
Brown | Orange | RS485 Data A + |
Orange | Yellow | RS485 Data B - |
Red | - | Power Pos - 12 to 28 VDC |
Black | Power Neg/Gnd - 0 VDC | |
Black (thick) | - | Ground / Cable Shield / PE |
- | Red | Power Pos - 5 VDC (not used) |
- | Black | Power Neg/Gnd - 0 VDC (not used) |
Brown | Terminator 1 - 120R (not used) | |
Green | Terminator 2 - 120R (not used) |
Installation Notes
The maximum DC power supply voltage permitted for the IMT Si-RS485 series solar irradiance sensor range is 28.0 VDC - accordingly for 24 V and 48 V battery banks/systems an appropriate Victron DC-DC converter (24/12, 24/24, 48/12 or 48/24) or AC-DC adaptor must be utilised in the installation.
For 12 V battery banks/systems the IMT Si-RS485 series solar irradiance sensor range may be powered directly from the battery bank and will continue to operate down to minimum voltage of 10.5 V (as measured at the sensor, account for voltage drop in the cable).
For detailed wiring/installation notes and specifications refer to the IMT Si-RS485 series solar irradiance sensor 'Quick Reference Guide' and Victron RS485 to USB interface cable ‘Datasheet’.
To ensure signal integrity and robust operation, particularly ensure that;
Extension cabling complies with the minimum cross-sectional area specifications in the related table - dependent on DC supply voltage and cable length
Extension cabling has appropriate shielding and twisted pair cores
The original cable attached to the Victron RS485 to USB interface is reduced to a maximum length of 20cm in installations where the total cable length is over 10m or there are installation/site specific interference issues – in this case appropriate/high quality cabling should be used for the entire cable length, rather than only for the extension length
Cabling is installed separated/away from the main DC or AC power cabling
All wiring is properly terminated (including unused wires) and properly isolated from weather/water ingress
The sensor housing is not opened or tampered with during installation - as sealing integrity will be compromised (and warranty void)
The IMT Si-RS485TC series solar irradiance sensor includes internal Galvanic Isolation (up to 1000V) between power supply and RS485 Modbus circuits, accordingly the non-isolated Victron RS485 to USB interface is suitable for most installations.
However, if an isolated RS485 to USB interface is preferred the only compatible device is Hjelmslund Electronics USB485-STIXL (any others type will not be recognised by the GX device).
Multiple Sensors
It is possible to connect multiple IMT Si-RS485 series solar irradiance sensors to a common Victron GX device, however a dedicated Victron RS485 to USB interface is required for each individual unit.
Multiple units cannot be combined on a single interface (as this is not supported by the related Venus OS software).
Configuration
There is normally no need for any special/additional configuration – the default ‘as shipped’ configuration is compatible for communication with a Victron GX device.
However, in cases where the IMT Si-RS485 series solar irradiance sensor has been previously used in another system and/or the settings changed for any reason, it is necessary to restore the default configuration before further use.
To revise the configuration, download the IMT 'Si-MODBUS-Configuration software tool'. Follow the instructions in the IMT ‘Si Modbus Configurator Documentation’. and check/update the following settings:
MODBUS Address: 1
Baud Rate: 9600
Data Format: 8N1 (10 Bit)
For further support related to configuration of the IMT Si-RS485 Series irradiance sensors please contact IMT Solar directly.
User Interface - GX Device
Upon connection to the Victron GX device and power up the IMT Si-RS485 Series irradiance sensor will be automatically detected within a few minutes and appear in the 'Device List' menu.
Within the ‘IMT Si-RS485 Series Solar Irradiance Sensor’ menu all available parameters will be automatically displayed (dependent on the sensors connected) and update in real time.
Within the ‘Settings’ sub-menu it is possible to manually enable and disable any optional/additional external sensors that are connected to the IMT Si-RS485 Series irradiance sensor.
2.12.1. Data Visualisation - VRM
To review logged historical data on the VRM portal, expand the ‘Meteorological Sensor’ widget list and select the ‘Meteorological Sensor’ widget.
Data from all available sensor types will be automatically displayed in the graph. Individual sensors/parameters can also be disabled/enabled by clicking on the sensor name/legend.
2.13. Relay connections
The GX device has potential-free Normally Open (NO) and Normally Closed (NC) relay functionality. This can be programmed via the menu to operate under a variety of conditions.
 |
ID | Description |
|---|---|
A | Fuse |
B | Programmable relay |
C | Generator, buzzer, warning light, alarm circuit, extraction fan and so on |
D | Battery |
 |
ID | Description |
|---|---|
A | Programmable relay |
B | Fuse |
C | Generator or alarm circuit |
2.14. AC load monitoring
All energy meter types can now be configured to a new "role": AC load monitor. This is done in the menu where you also choose between Grid, PV Inverter and Generator. With AC load monitor selected, the load will be shown in the Device list.
Please note that such metered loads are not used in any calculations, just monitoring.
