https://drzwave.blog/2021/02/16/jasco-motion-dimmer-explained/
The Jasco Motion Dimmer is an ideal Z-Wave product for home automation. We want the lights to come on automatically when we enter a room and off again when everyone has left. The motion sensing needs to be reliable and sensitive and ideally not involve changing batteries every few months. Thus, a wall mounted, always-on dimmer with a built-in motion sensor fits our needs perfectly. In this blog article I’ll explain a few tricks to getting the most out of this handy device.
Configuration Parameters
The Jasco Motion Dimmer has 18 configuration parameters. The parameters can be set by reading the documentation and then programming them using complex combinations of button presses. But, with a Z-Wave device, it’s much easier to program them via Z-Wave. Most Hubs allow you to program the configuration parameters though the process to do so is different with every Hub. The parameters are briefly described on the Jasco web site ezzwave and on the Z-Wave Alliance web site. However, these brief descriptions don’t clearly describe what the parameter does and more importantly, what the best settings are to get the most out of this device.
Several parameters are two bytes instead of just one even though the value will typically fit in one (the value is 0-255). The parameters listed with a (2) in the Name field below means they are two bytes. If there is no (2) in the name then just send one byte. Sending just one byte to the 2 byte parameters can confuse the dimmer and it may not set the parameter to the desired value. The result is frustration as you sent it your desired value but it didn’t take it or set it to what appears to be some random value. Always send the proper number of bytes for each specific parameter. Some Hubs will handle this for you, but others must be done manually.
See the blog post for the table.
Dimming Ramp Rates
When a dimmer changes the light level from 0 to 100%, the time it takes for the light to go from 0 to 100% is set by the Ramp Rate. The dimmer has six parameters related to the dimming ramp rate, parameters 7 through 12. The ramp rate is configured using a pair of parameters for three different methods of changing the light level. The “Steps or Levels” is the number of dim levels that the light level changes every Time Step. Always leave the Steps at the default of one. Anything more than one results in the light level “jumping” from one step to the next while dimming. This jumping is just plain unpleasant so always leave Steps at one. The Time Step parameter (Speed) is how often the Step is added to the current dim level in 10 millisecond increments or every 1/100th of a second. Since the dim level goes from 0 to 100 and it takes 1/100th of a second to increment once, then the Time Step simply is the number of seconds for the dim level to go from 0 to 100%. The default ramp rate is three seconds which is what most people expect and in general is a good value.
The three pairs of ramp rates provide different ramp rates based on the method to turn the light on or off.
- Z-Wave command – parameters 7 and 8
- Button or Motion detection – parameters 9 and 10
- All On/Off commands – parameters 11 and 12
The easy ones to ignore are the All On/Off parameters as the Z-Wave All On/Off commands are obsolete. Simply leave these at the default. The remaining two pairs can be used for different purposes based on what is changing the light level. I recommend leaving the Button/Motion parameters at the default of 3 seconds. This is the expected ramp rate of the average dimmer. When a person presses the button or motion is detected, they expect the dimmer to react at about this speed. Setting it to less than 3 seconds results in the user being unable to set a mid-level as the ramp rate is too fast to accurately stop at a mid level. The dimmer pretty much becomes a switch. Setting the ramp rate to more than 3 seconds will quickly become annoying as it just takes too long to get to the desired level. That leaves the Z-Wave command ramp rate parameters. These can definitely be programmed to be longer, potentially much longer so that the level changes quite slowly and an occupant can override the slowly changing light level by pressing the button or waving their hands in the air so the motion sensor will detect them.
The Z-Wave Multilevel Switch command Version 2 includes a Duration field which is the number of seconds to go from 0 to 100% or the ramp rate. If the Hub sends a dim level command with the Duration field, the configuration parameters are ignored and instead the ramp rate is set to the Duration value in the command. Some Hubs let you assign the Duration field but most only support Version 1 which only has the level and no duration which the dimmer will then use the configuration parameters dim rate.
Association Groups
Three association groups are supported with up to five NodeIDs each. Your Hub should automatically assign itself to Group 1 which is the Lifeline group. The Lifeline group is required for every Z-Wave Plus device and identifies the NodeID where any state changes will be sent. The dimmer sends your Hub commands whenever the sensor detects motion or the state of the local load changes (someone presses the On or Off button). Thus, it is very important that the Hub be assigned to Association Group 1 so Hub app on your phone matches the actual state of the dimmer.
Groups 2 and 3 are identical and simply send Basic On/Off commands to the associated NodeID. Assigning a NodeID to these groups will send a command to turn the NodeID either On or Off when motion is detected or not. Assigning a NodeID to these groups enables the motion detector or the buttons to turn on/off other lights in a larger room quickly. Using the association groups is fast since the dimmer sends the Z-Wave commands directly to the light and works even if the Hub is offline for some reason.
Multi-channel associations are supported but generally you want to avoid them. Multi-channel adds another layer of encapsulation to every frame which just slows everything down. The only time you might want to use multi-channel association is if you wanted to control a specific outlet in a power strip with the motion sensor. Multichannel would be required to choose which of the outlets in the power strip to turn on/off. However, I recommend that you let your Hub do complex operations like this and keep things simple with the dimmer.
| Group | Name | Description |
|---|---|---|
| 1 | Lifeline | Motion Sensor readings and status of the load are reported |
| 2 | Basic On/Off | BASIC SET On or Off commands |
| 3 | Basic On/Off | BASIC SET On or Off commands |
Association Groups
When a NodeID is assigned to an association group, the node will be interviewed and depending on the command classes the node supports, the dimmer will send different commands. Specifically, if the device supports CRC16 then the commands will be encapsulated in CRC16 which improves the reliability of the command being delivered without errors but isn’t really necessary.
Why are there two association groups you ask? The reason is to match the feature set of many other Jasco Z-Wave products which send different commands in the two groups. But for this device it always sends the same commands from either group. My recommendation is to not use Group 3 at all. If you want to associate other lights directly with the dimmer, use Group 2.
Recommendations
There are many ways to use a motion sensor wall dimmer. Perhaps the toughest question is where to install it? The first place I installed my motion dimmers are in hallways. When your arms are full of groceries, you want the lights to just come on when you enter. More important in my household is that the lights go OFF shortly after everyone has left the hallway! Back in the bad ol’ days, the hallway lights were always on all the time because no one ever turned them off! The challenge with hallways is typically they are 2, 3 or more way lights so the placement of the motion sensor is key. Jasco makes an inexpensive Add-On Switch that connects to the Traveler wire to enable the multi-way switch so it can be operated manually as before. However, getting the motion sensor to cover a long thin hallway can be difficult since the motion sensor is built into the wall and cannot be pointed down the hallway. In that case you may need to use a separate battery powered motion sensor to trigger normal dimmer switches. What this means is that a wall mounted fixed position motion sensor may not work for all situations but the sensor has a wide angle lens so it will work most of the time.
Easy Mode – Use the Defaults
The simplest configuration is to use the dimmer as-is using the default settings. The defaults work as you would expect and obviously is the easiest to setup and use! Perhaps the only real decision here is which wall switch to replace. In this mode the lights come on when motion is detected and off after 10 minutes. Perhaps the one configuration to adjust would be the Timeout especially for hallways. Since you’re usually passing thru the hallway and thus moving quite a bit, the Timeout can be short, one or two minutes. A short Timeout keeps the power consumption to a minimum while providing sufficient light to travel thru the space.
Slow Dim – Parameter 8
The next parameter to consider customizing is the Z-Wave dim ramp rate (Parameter 8). The motion sensor and the buttons continue to use the typical 3 second ramp rates which are what people would normally expect. But when a Z-Wave command sends a command to change the light level, a significantly slower ramp level can be used. This configuration lets the user override the dim level either by moving or pressing a button. The slow ramp can be 30 seconds in this mode or perhaps as short as 10s. This always gives the person in the room time to override the slow dim but still provide enough light to move around the room as needed. The most common case for this is in a room where people might be reading, watching TV or working on a computer where they are not moving very much.
Manual Mode – Parameter 3
Configuration Parameter 3 has three different settings. The default is Occupancy mode which is the most useful and common mode. Vacancy mode only turns the light off but you have to manually turn it on – don’t bother with this mode. The third option is Manual mode which disconnects the motion sensor from the local load. Your Hub has to then turn the light on when the motion sensor detects motion. The time from motion detection to the light coming on has just a little more delay but often this delay isn’t that much. What you gain from this setup is a great deal more flexibility in how the lights should dim up or down.
My Setup
The first motion dimmer I installed was in my mudroom which is pretty much a hallway with a closet but it is an L shape. It is a 3-way switch with wall switches at each of the 3 entrances. Fortunately the switch with the incoming power is the one with the best view down both legs of the L and is where I mounted the motion dimmer. I use Easy Mode in this situation since the desired operation is quite simple. You walk in, the lights come on, you leave and 10 minutes later the lights go off. I suppose I should shorten the Timeout but I’ve never been in the mudroom and had to waive my hands to turn them back on even when rummaging thru the closet where the motion sensor can’t really see me. If I made the timeout shorter, then the lights might go off before I’ve found what I’m looking for. Nothing craters the WAF Factor more than the lights turning off before my wife has found what she’s looking for in the closet!
The next one I installed is in the garage. In this case I used a Motion Switch rather than a Dimmer since its a few bucks cheaper and I don’t need a dimmer in the garage. Easy Mode is fine in this situation. I have a 2 car garage about 24′ square and the motion sensor is able to detect motion of a person just about anywhere in the room even though the wall switch is in the corner next to the door into the mudroom. I did change Motion Sensitivity (Parameter 13) to high to get the entire garage to detect motion. I also enabled Light Sensing (Parameter 14) as my garage has quite a few windows and has plenty of light during the day. There is no way to adjust the level of light to disable the light from turning on but it seems to work when I want it to and doesn’t turn on the lights when the room is sufficiently bright from natural sunlight.
My master bedroom closet seemed like a simple setup but took a little more tweaking. What I want is the light to come on at a low level (say 5%) but if it’s daytime or early evening I want the light to come on fully. With this setup the light is just enough to find my robe in the middle of the night without waking my wife but she can choose an outfit in full illumination. Since the dimmer has no idea what time of day it is, I need to enlist the help of my hub. I set the Switch Level (Parameter 17) to 5% and the Z-Wave Dim Rate (Parameter 8) to 30 seconds. Then I created an event on my hub (Homeseer) that sends an ON command whenever motion is detected and the time is between sunrise and 9pm. This ON command will take 30s to come on fully which is nice. Since the Button Dim rate remains at 3s the buttons operate as normal so if my wife is impatient she can press the top button to quickly get the lights fully on.
My kitchen is the most complicated setup by far. First of all, I have an eat-in kitchen which is pretty wide and the dimmer often doesn’t detect if we are sitting at the table which is at the end of the kitchen. The Jasco Motion sensor is mounted basically in the middle of my kitchen and there are a variety of kitchen appliances on the counter blocking the view of the kitchen table. To cover this wide space I enlist a second motion sensor that is close to the table so even if someone is sitting there quietly, perhaps reading, the combination of the two sensors ensures that the lights only go off when no one is there (most of the time). I use Manual Mode (Parameter 3) in this case and rely on my Hub to combine the 2 sensors readings and control the lights appropriately. Manual Mode effectively disconnects the Jasco Motion Sensor from the Dimmer. When either motion sensor detects motion, I set the dimmer to full on. When BOTH motion sensors have not detected motion for about 20 minutes, then I turn the dimmer off. By relying on the smarts of my Hub I can do even more interesting events where the timeout is different late at night when someone is probably just passing thru and I can use a lower dimmer level. At meal times I push the dimmer fully on as we’re probably preparing food so the more light the better. I could even check for the light level provided by the windows in the room and then only add as much illumination as needed though I haven’t experimented with this yet.
Conclusion
Once you have a few lights automated, you’ll almost never touch the buttons. The lights come on when you walk in and off when everyone leaves. Your family quickly becomes used to it and it blends into the woodwork which is the way things should work. Adding motion sensor lights to your home is an incremental upgrade. I suggest starting with your most-used light such as a hallway or mudroom. Once the family has adjusted to one, you can add more in other locations as the budget allows.
The Jasco Motion Dimmer is a versatile and invaluable home automation device. Never needs batteries and is configurable enough to handle even fairly complicated situations. The trick is to use the right tool for the job. The dimmer is fine for basic operation but use the smarts built into your Hub to do more complicated tasks. Being highly configurable unfortunately results in more complexity but I hope my guide helps you make the most of this device. Let me know what you think and any other Z-Wave related topics you’d like to discuss in the comments below.