The DM825 has been designed to control just 8 elements, how can it be used to control an entire building?
The DM825 can control up to 8 groups not just 8 nodes, each group can consists of dozens of nodes, as long as all the nodes in a group has a logical ordering, e.g. all nodes are hallway lights. Especially for scheduled control where all the elements need only to simultaneously turn on and off, then there is no need to set each element individually.
Note: If for example, a hallway has two sections, east and west, where each section has its own time schedule, then the two sections are separate groups.
How can one group together nodes which are widely spread out?
Most applications will be using either the LT3100 or the LT3504 terminal unit. To set the group to which each node belongs to, simply plug in an IS45 to configure the grouping. No special tools or software is needed. This set up is repeated for each of the spread out TU until every one is configured to the same group.
How to set up the DM825 network?
(1) Connect the Ethernet port of the DM825 to an Internet access node.
(2) Obtain an IP address from the network administrator, then set the DM825 to this IP using a browser such as Internet Explorer.
(3) Network all the TUs together with the DM825 using the D-bus.
How is the schedule set through the DM825?
(1) By setting through a fixed time, for example: at 8:00 p.m., turn on groups 1, 3 and 5; turn off groups 2, 4 and 6. At 10:00 p.m., turn on groups 2, 4, 6 and so on.
(2) 10 time slots can be set each day.
(3) The DM825 is not device based, one does not select the device first then set the time.
How about for weekends, which are non-working days?
The DM825 provides two sets of schedules which can set separately, each day of the week can be assigned to one of the two schedules, the most common usage is to assign schedule A to weekdays and schedule B to weekends.
How about holidays and other special days?
Using the web interface, one can assign certain days as special days, for scheduling, these days are treated as weekends.
What about for extended periods such as school breaks?
(1) One can change the schedules, and the new schedules will be in effect.
(2) Certain groups could be exempted from the schedule, and these groups would be manually controlled, typically during these periods they would simply be turned off completely.
What is the best way to proceed during the extended break periods when the lights are under manual control?
The lights can still be manually operated using the IS45D switches.
What if a situation demands that a node be controlled separately?
This would require the installation of an IS45D digital switch, the IS45 can be networked with the DM825 and the TUs together on the same D-bus. The IS45 can then be set up such that each switch correspond to an individual TU load.
(1) The DIP switch on the IS45 can be set to correspond with the device address of the LT3100 or the LT3504.
(2) Each button on the IS45 can then control a single load on the TU, the on/off status will automatically be shown on the corresponding IS45 button.
Can the IS45D be used to control a group?
Yes, the IS45D has group control mode in addition to its individual control mode.
Can the IS45D be controlled through the Ethernet network?
Yes it can be controlled through the DM825.
How can I manage the DM825 for each building?
Using any Internet enabled computer, select the IP for the desired DM825, enter the password, then view that status of that particular DM825. One can see the group status, whether on or off (but not individual nodes); the control mode as scheduled or manual. Of course, one can also change the schedule, manually send a control command a group regardless of the schedule or return to automatic control.
Can the DM825 be used to control individual nodes?
It can be done by assigning a group to just that node.
Is the DM825 susceptible to viruses?
No, the DM825 is not a PC or other embedded PC based product, it has its own special CPU.
What happens when the Ethernet network goes down, what happens to the DM825?
The DM825 operates independently of the Ethernet network, so if the network goes down it does not affect the DM825, all the automated functionality, i.e. the time schedule control is still in effect; insuring a high degree of robustness. The only thing is that the DM825 won't be able to link to the network and hence administrator won't be able to see what is happening with the DM825.
What actions needs to be taken when the power is restored after an interruption?
Nothing needs to be done as the DM825 will automatically restart and perform its regular tasks, except that the schedule based control will need to wait until the next time slot before taking effect.
Can the schedule be tampered with?
The DM825 is protected by a password and changes cannot be made unless one is authenticated first.
For facility control, how does the DM825 compare with the HMI of a DDC?
(1) When it comes to scheduling, the DM825 has similar functionality and compares well with more costly DDCs.
(2) Most HMI software is based on a host PC, so when the host PC crashes, then the entire system and the scheduling goes down with it. In contrast, the DM825 is independent of a PC and is much more reliable.
(3) An HMI does not have the equivalent of the IS45D for redundant control.
(4) Of course, the HMI is more graphically appealing and one can view the status of individual nodes.
(5) The DM825 is web based, while he HMI software is limited to the host PC that it is running on and cannot be viewed from another PC, or it can be web based but which would then require that it have its own web server.
Can you briefly describe how to set up the schedule control for all the buildings in a university campus setting?
(1) Install one or two DM825 in each building and connect the lighting and ventilation to use either the LT3100 or LT3504. Then set up the groups.
(2) Then set up the schedules using the web interface of the DM825.
How to use this in a classroom setting, where the biggest headache is having the lights on with no one around?
Just connect the lights in the classroom to the TU and network them together with the DM825. Replace the regular light switches with the K20 delay switch. At the scheduled time, when the power to the lights is supplied, the lights will still not turn on unless the switches are also activated.
When a regular switch is in the 'on' position, the lights will turn on when the power is supplied, but with a K20 smart switch, the lights will only turn on when it is manually pressed. So for example we have this schedule:
At 7:30 in the morning, the power is enabled, but the lights won't turn on automatically unless the K20 switch is manually pressed.
At noon, the power is disabled for one hour. So the lights will turn off.
At 1 pm, the power is enabled once more, and by the same reckoning, the lights will only turn on when the K20 switch is manually pressed.
At 6 pm, all the power is scheduled to be turned off, but one can override this by enabling the power locally using the on-board switch of the TU, once enabled, the lights can be turned on through the K20.
At 10 pm, the power is simultaneously turned off until the next day.
How about for dorm rooms when the lights are scheduled to be turned off at midnight, but the students still need time to study until 2 am for exams, how can we handle this situation?
Connect the room lights to the TUs and network them together with the DM825. Replace the regular light switches with the K20 delay switch.
(1) For regular days, the DM825 is programmed to automatically turn off the lights at midnight. During these days the K20 switch won't work since there is no power to the lights at all. Then the power to the lights are once again enabled the next day, but the lights will only turn on when the K20 switch is manually pressed. Thus saving power by not having the lights on unless necessary.
(2) For the days before a big exam, the schedule is extended such that the power is on until 2 am. The rest would be the same as situation (1).