Why choose relay operated electric blinds?

Low cost mobile app or voice control

Furthermore, if you are looking for an easy and low cost method of controlling blinds by mobile app, and by voice assistant - then the majority of the solutions on the market are low cost hubs which a user can connect to via WiFi or mobile (3G/4G) from their mobile phone, tablet or laptop using an app or web interface. Examples of these hubs include Louvolite One Touch Home Hub and Somfy TaHoma Switch.

Commands initiated from the app or web interface are translated by the hub into a radio signal which is received by the blind. These hubs can sometimes be connected to voice assitants such as Amazon Alexa and Google Assistant, allowing you to initiate a blind operation by using a voice command. Again, this command finds its way to the blind as radio signal. In short, radio motors, rather than relay motors are used with these types of low cost hubs.

That's not to say that you can't control a relay operated blind with a voice assistant. But this is more likely to be a bolt-on feature of a wider home automation system, which we'll talk about below.

Smart home or Building Management Systems (BMS)

If you have a smart home system, or if you are buying blinds for a commercial property to integrate with a building management system, then the method of linking the motors to the central home automation system or BMS depends on the type of blind motor that you are using. 

Let's summarise the method by which both types of motor are controlled in this scenario:

• Radio operated blinds + a bridge device: Blinds using motor incorporating a radio receiver are usually controlled by handset or wireless wall switch. A bridge device simply extends the connectivity of the motor so that it can be part of a wider control system. The bridge device is normally wired back to the central smart home system or BMS (building management system) and translates a command from the central system into a radio signal which can be received by the blind motor in order to operate it.
• Relay operated blinds + a blind control (relay): A relay operated electric blind is a roller blind with a motor which can controlled using a hardwired blind control (also known as a relay). A mains relay unit is connected back to a hardwired blind control (relay) which is part of the smart home system or BMS. The wired blind control (relay) translates a signal sent by the system into a conrol command by providing directional power at 230vAC to switch your blind up and down. 

Whilst a radio operated blinds can be controlled by solely by handsets and wireless wall switches, a relay operated blind can only be controlled by a wired controller. So if you are considering relay operated blinds, it is likely that you are buying them to integrated with a smart home system, or with a building management system.

What are the advantages of relay operated blind?

Reliability

The key advantage of a relay operated blind system is its reliability. The control method is wired, meaning there is a line of cable from the relay unit that is switching and controlling the blinds to the blind itself. There is very little that can go wrong between the relay unit and the blind. Some home automation technicians that I have worked with in the past will not work with wireless technology and will only work with wired devices, as they worry about wireless technologies being unreliable due to interference and range issues. 

Range

As intimated above, wireless technology does have a finite range. Typically if you are controlling radio operated blinds from smart home system, the bridge would be positioned in the same location as the home automation system hardware. Where home automation systems or BMS systems are installed, these typically have their own room or cupboard somewhere within the property - it might be in a loft, or in a "comms" room or office. In larger properties, the blinds themselves might be a considerable distance away from the bridge device. Although the range of these devices is typically extremely good, at the planning stage, some home automation technicians would rather avoid the risk of a device failing. 230vAC wired motors are often used because a cable can simply be laid from the blind controller to the blind itself providing a reliable line of control over distance.

Lower Cost

Relay operated blinds are generally a lot lower in cost. Firstly, they do not include a radio receiver which reduces the cost per unit. Also, radio operated motors generally use the propreitory radio protocol of the manufacturer. In the case of larger brands like Somfy, this radio protocol (RTS) is used accross many different devices. This protocol and excellent connectivity is a key part of their brand. It has an associated R&D cost but also enables them to charge a premium for their brand and for their radio motors.

Relay motors are generally a simpler mechanism and standardised accross the many different providers. This simplicity and the competition between motor manufacturers also results in lower prices for this motor type.  

What are the disadvantages of relay operated roller blinds?

Whilst relay motors are reliable, simple and low cost - there are additional considerations that you will need to take into account when buying blinds with this type of motor. I'll out-line these considerations below. These factors may (or may not) be considered as disadvantages depending on where exactly you are in the planning/rennovation process and what you are trying to acheive.

Other costs!

The motors are lower cost BUT:

• You will also need to provide a relay per motor - which has a cost assocated with it.
• You will need to conceal the relay (maybe in a cavity or media or "comms" room) and lay cabling from the location of the relay to the location of the blind - of course this cabling and the labour in installing it also has a cost associated with it.
• You will need to configure the relay (possibly setting a maximum run time) and "integrate it" (make it work with) with your smart home system - for some systems like Fibaro and Lightwave, this can be a DIY task, if you are that way inclined. For other systems such as Control4, Crestron and Lutron, this will require a home automation technician, which is also an additional cost which you will need to take into account.

Whether these additional costs outweigh the savings made by a lower cost motor will depend to a certain extent on the costs being charged by your home automation technician for the blind controls and the labour required to implement it. At the DIY end of the market, the costs of the hardware may be lower and some of the labour may be "DIY" and therefore no cost.  

Planning in advance

You'll need to plan ahead:

• As mentioned above, each blind needs its own relay and this will need to be housed appropriately
• Each relay will need its own mains power supply.
• Appropriate cabling will need to be run between the relay and the blind.
• This cabling is normally run in containment behind plasterwork, which means that you'll need to plan for this to happen at a stage in your build/rennovation before plasterwork and decoration has been completed.
• You'll need to consider how you will terminate this cabling and then how it is to be connected to the motor cable
• The cabling needs to be of the appropriate type (number of cores) and possibly provide some flexibility for changes of motor and blind specification. Somfy radio motors are usually 2-core, NEWBLINDS radio motors are 3-core, Somfy relay motors are 3-core, NEWBLINDS relay motors are 4 core. We suggest laying 4-core cabling to allow for each of the above to be accomodated.

None of the above is necessarily a disadvantage.. unless of course you are reading this for the first time at a stage in your build where the plastering and decoration has been completed!

Functionality

There is some functionality that will not be available with relay operated motors, versus radio motors which are often more inteligent:

• Upper and lower limits on relay operated blinds tend to be mechanical, meaning they are set using allen keys which are adjusted to restrict or allow travel in either direction. Radio motors tend to have digital limits, which are set a the touch of a button, or using a sequence of buttons! Each method of limit setting can be a bit fiddly - but you generally only have to do it once!
• Because the limits on relay operated motors are mechanical and the motor is "dumb" (i.e. not inteligent), the mechanical limit is a hard limit. The blinds stop at the limit quite abruptly. Radio motors tend to be more inteligent and as such often come with in-built functionality such as "soft stops" where the motor slows down before docking at the upper or lower limit.
• Radio operated blinds, being digital, are able to store intermediate positions. Somfy Radio motor (the Sonesse 40 RTS) for example is able to store one intermediate position which they refer to as the "MY" position. Somfy controls come with an UP, DOWN and MY button. NEWBLINDS Radio motors have the ability to store up to 6 intermediate positions. Relay operated motors, regardless of brand, do not have the facility to store an intermediate position. So there is only the facility to set an upper and lower limit via the motor. Intermediate positions, if required are often acheived using the intelligence of the smart home system or BMS to which the blinds are connected. For example, if a blind takes 20 seconds to run between top and bottom, your home automation technician may configure a mid-point position by setting up a command for the blind to run for 10 seconds from top towards the bottom limit. Some home automation systems, such as Fibaro, have a "slider" interface, and are able to calibrate the motors so that the slider can move the blind to a percentage open or closed position using the slider.

As mentioned at the start of this post, if you are considering a relay operated motor, then it is more than likely that the reason you are doing this is because you wish for them to be controlled by a home automation system or a BMS. And the traditional and most reliable way of doing this is using relay operated motors.

Integration method for Radio Motors - an alternative!

Somfy Radio motors (either 230vAC, 12vDC or battery) can be integrated with smart home systems using bridge devices such as the RS485 RTS interface or the Dry Contact RTS Transmitter. The RS485 RTS transmitter has 16 channels so can control up to 16 RTS devices, or 16 groups of RTS devices. The dry contact RTS transmitter is single channel only, so is great for controlling one blind or one group of blinds. However, as mentioned above, many smart home technicians prefer to use traditional wired (relay) technology over wireless (radio) technology to eliminate the risk of interference and over-come range concerns.

Relay is reliable and low cost

Whilst we have outlined some potential cost, planning and functionality considerations relating to relay operation above - these are not necessarily disadvantages if you have the correct budget (or DIY capabilities), if you have planned early and planned correctly and if your smart home system is able to provide centrally some of the intelligence that is not incorporated in the motors themselves.

In summary, relay operated electric blinds are reliable and low cost. They use technology that is familiar to most smart home or BMS technicians and which can easily be incorporated into the vast majority of smart home systems and BMS.