The MHTi-EM device is a CC driver with internal battery that can drive a load at 8W for 90 minutes. The battery is recharged during normal use. Connect the battery back device to one of the output channels of an MHTi-NODE-90-CCRS485. When the NODE-90 is powered from PoE it passes through a constant voltage to charge the battery and sends dimming commands. If the PoE is disconnected or otherwise unavailable, the MHTi-EM changes to discharge mode. It limits the output power to 8W such that the internal battery discharges for at least 90 minutes.
Wiring
Consider a dual use NODE-90. Actuator channel 1 is connected to non-emergency lights. And channel 2 is connected to emergency lights via the MHTi-EM battery backup device. Small lights like 10W rated can easily be wired in parallel. Both emergency and non-emergency lights will respond to dimming controls from an MHTi wall switch during normal PoE operation. However, if PoE is interrupted then the wall switch stops functioning and the MHTi-EM battery backup device changes to discharge mode to power the emergency lights. During emergency the non-emergency lights will not be powered. Only the emergency lights will continue for at least 90 minutes at 8W total load. If multiple lights are wired in parallel then the 8W will be divided between them where each would receive a fraction of the total.
If the parallel lights are too dim for proper illumination, then use a MHTi-EM for each emergency light. Each light will be powered at the full 8W during emergency discharge. In non-emergency normal operation the light will operate logically in parallel and responds the same to channel 2 dimming.
Commissioning
At least one of the actuator channels must be configured for battery backup mode. This mode will send dimming commands to the battery backup device during normal operation. If the mode is not enabled, then the actuator output will dimmed by PWM disturbing the constant voltage which will cause the battery backup to malfunction. Hence ensure the MHTi-EM and connected node are commissioned properly.
It is possible to use more than one MHTi-EM connected to each actuator channel of the NODE-90. The dimming channel is separated by the node. However, the RS-485 network is common so the same command would be sent to all battery backup devices. On special request the MHTi-EM could be manufactured with different address to distinguish the channels. Multiple channels is not standard, so expect to use at most one unique battery backup channel with each NODE-90.
Commissioning can be done from the console using the set_cccv command.
set_cccv 1 10 # set channel 1 to battery backup mode
set_cccv 2 10 # set channel 2 to battery backup mode
set_cccv 3 10 # set both channels to battery backup
Power should be limited for the associated actuator channel. This can be done from the console using the set_max_watt command.
set_max_watt 1 500 # set channel 1 battery backup power to 50.0W maximum load
set_max_watt 2 500 # set channel 2 battery backup power to 50.0W maximum load
set_max_watt 3 250 # set both channel battery backup power each to 25.0W maximum
The dimming for each channel can be adjusted from the console using the set_dim command. If the node is configured for the actuator battery backup mode, then the dimming command will be sent to the MHTi-EM and the load should be driven accordingly.
set_dim 1 50 # set channel 1 battery backup dimming to 50%
set_dim 2 50 # set channel 2 battery backup dimming to 50%
set_dim 3 50 # set both channel battery backup dimming to 50%
Testing
- Connect a load to the MHTi-EM.
- Connect the MHTi-EM to the NODE-90.
- Connect the battery for the MHTi-EM.
- The load should be powered at 8W by the battery backup.
- Connect PoE to the NODE-90.
- After the node starts up the load will be driven according to the dimming.
- Try changing the dim value and observe the change to the load.
- Press the Test switch on the MHTi-EM.
- Observe the load change to battery backup discharge power at 8W.
- Release the Test switch.
- Observe the load return to previous dimming level.
- Disconnect the PoE to the NODE-90
- Observe the load again change to battery backup discharge