These Two-Way Modules can be controlled using standard X-10 commands such as A1-ON. They are therefore compatible with the entire range of existing X-10 controllers. However when used with the CM11A Two-Way Computer Interface and ActiveHome software they can be polled for, or automatically transmit their status. Technical Sidebar below (for programmers who want to develop applications that take advantage of the advanced features of these Two-Way Modules) THEORY OF OPERATION OF TWO-WAY LAMP AND APPLIANCE MODULES
Two-Way Lamp and Appliance Modules with Status Polling, Automatic Status Response, and Automatic Gai
Two-Way Lamp and Appliance
Modules with Status Polling, Automatic Status Response, and Automatic Gain Control (AGC)
These Two-Way Modules can be controlled using standard X-10 commands such as A1-ON. They are therefore compatible with the entire range of existing X-10 controllers. However when used with the CM11A Two-Way Computer Interface and ActiveHome software they can be polled for, or automatically transmit their status.
Technical Sidebar below (for programmers who
want to develop applications that take advantage of the advanced features of these Two-Way
The X-10 Two-Way Lamp and Appliance Modules are the latest in the range of X-10 Two-Way Modules. When used with the X-10 Two-Way Computer Interface (CM11A) and ActiveHome software they provide the most versatile (and cost effective) high-end Home Automation solution available today.
There are 3 types of Module available. The AM14A Two-Way Appliance Module is a 2 pin polarized Module; the AM15A Two-Way Appliance Module has a 3 pin grounded plug and socket; and the LM14A is a Two-Way Lamp Module.
These Two-Way Modules can be controlled using standard X-10 commands such as A1-ON. They are therefore compatible with the entire range of existing X-10 controllers. However when used with the CM11A Two-Way Computer Interface and ActiveHome software they can be polled for, or automatically transmit their status. Two-Way Lamp Modules can even be polled for, or automatically transmit their present brightness level. Two-Way Lamp Modules also have a feature called soft start. This means that they fade up from zero to the specified brightness level when turned on. They also fade off. This is not only aesthetically pleasing, but also extends bulb life.
In its default state when the Module is polled for its Status, it responds with its on/off status in the same code format as existing X-10 Two-Way Modules such as the RR501 Transceiver Module and the PR511 Floodlight Motion Detector. This allows existing software and hardware designed to work with the RR501 and PR511 to automatically work with these Two-Way Modules.
Automatic status response
The Two-Way Modules can also be configured from the ActiveHome software to automatically transmit their status when turned on either from the CM11A computer interface and ActiveHome software or from any other X-10 controller. They can even transmit this change in status when turned on locally (by cycling the on/off switch on the connected light or appliance).
The acknowledgment is not simply sent after the command is received. The Module monitors the output status of the relay or switching circuit, and only acknowledges after the output has changed state. Therefore any failure of the hardware (a blown bulb for example) is communicated back to the controller.
Enhanced Reliability with Automatic Gain Control (AGC)
The X-10 communications protocol has, over a 20 year track record, proven to be the most reliable powerline Home Automation protocol available. The addition of Two-Way communication and automatic software retries take reliability to a new level. X-10 Two-Way Modules also fully implement collision detection and contention resolution ensuring even complex Home Automation systems will run smoothly. And the addition of Automatic Gain Control (AGC) ensures that the Modules operate reliably even in the most harsh conditions. As long as there is always at least twice as much signal as there is noise, the Two-Way Modules with AGC will always operate even if there is several volts of noise on the AC wiring.
Unlike other systems which require that ALL Modules in the system be fully Two-Way, X-10 systems can be built from a mixture of Two-Way and standard Modules. Critical items such as water heaters, air conditioners etc. can benefit from Two-Way control, while lighting can be controlled with standard Modules if desired.
Technical Sidebar below (for programmers who want to develop applications that take advantage of the advanced features of these Two-Way Modules)
Lamp Module, LM14A
Response to "Standard" X-10 commands
The LM14A responds to the commands ON, OFF, BRIGHT, DIM, ALL LIGHTS ON, ALL UNITS OFF, ALL LIGHTS OFF, and STATUS REQUEST, as detailed in a separate document on X-10's Extended Code Protocol (document XTC798) available upon request from X-10.
Automatic Message Response
In the default state (after an initial power up) the unit does not automatically answer commands sent to it (except STATUS REQUEST). If the EXTENDED Command CONFIGURE (Hex 3B) (see document XTC798) is sent with the AUTOACK 'STANDARD' bit set in the DATA Byte, the unit automatically answers any message sent in "Standard" X-10 format that requires the unit to be "addressed" and which changes its output state. In practice, this means the unit auto-acknowledges the ON, OFF, BRIGHT, and DIM commands. The response is the EXTENDED OUTPUT STATUS message (Hex 38) with the DATA byte containing the 6-bit brightness level, together with the LAMP MODULE ID bit ('0' for a Lamp) and the OUT O.K. bit set. The response is not made until the unit has actually reached the output level it was told to go to. This could result in a response delay of up to 2.75 seconds in the case of a FADEON or FADEOFF from FULL BRIGHT.
Since the unit has no permanent (nonvolatile) memory, after a power loss the unit performs a memory check and if memory has been lost it transmits the EXTENDED REQUEST for STATUS (Hex 37) with a DATA byte (xx01xxxx). The CM11A Two-Way Computer Interface then issues a command to reconfigure the Module and reset its output state.
Output Status Byte
This byte contains 3 pieces of information. Bits 5-0 give the current brightness level as a number between 0 and 63, bit 6 set to '0' indicates the unit is a Dimmer. Bit 7 = '1' means that the bulb is connected and the Triac is performing correctly. Hardware restrictions limit this check only to be made on a negative half Mains Cycle, but, being a dimmer, the Triac output is tested both in the Off and On state.
Sense (Local Control)
If the Load Switch is opened then closed, the unit Fades on to its MEMORY brightness level. If either of the AUTOACK bits are set in the CONFIGURATION byte (command Hex 3B) the unit automatically sends its OUTPUT STATUS ACKNOWLEDGE message in EXTENDED format (Hex 38). The message is not sent until the output level reaches the MEMORY value. This can take up to 2.75 seconds.
Response to "Extended" X-10 commands
The LM14A responds to the extended messages described in document XTC798. When a message results in the unit altering its OUTPUT level, the change is made smoothly at the normal dimming rate. In the default state the unit does not acknowledge EXTENDED messages, but if the AUTOACK "EXTENDED" bit is set in the CONFIGURE byte (command Hex 3B), any EXTENDED message that is not Broadcast (i.e. specific to that Housecode and Unit Code) and which alters the output status causes the unit to automatically acknowledge with the STATUS ACK message (Hex 38). The response is not made until the unit achieves the output level indicated by the command. This may take several seconds (see earlier). In practice, the unit only automatically acknowledges the PRESET OUTPUT message (Hex 31). Although not used for EXTENDED messages, the MEMORY is always the current OUTPUT BRIGHTNESS level if the output is ON, and can be used by subsequent "STANDARD" X-10 messages. EXTENDED messages reset the "ADDRESSED" status of the unit.
In order to do Scene Dimming the unit can be made to belong to a group or groups. When a Broadcast message is sent to activate that group response, all units in that group simultaneously fade to the brightness level assigned previously to each individual Module. The unit can belong to 4 groups simultaneously. The groups can be GLOBAL, in which case there are only 4 available, or can be relative to a GROUP REFERENCE no. (1-16) in which case there are 4 x 16 available. A unit can only belong either to Global groups or Relative groups at any one time (not both simultaneously). A unit can be programmed into a Global group at a predetermined output state using the INCLUDE IN GROUP command (Hex 32) or at its current output level using the INCLUDE command (G1G0 00 xxxx) (Hex 30). However, it can only be put into a RELATIVE group at its current output level by using the INCLUDE command (G1G0 11 S3S2S1S0) (Hex 30). In effect, the GROUP REFERENCE is the unit code of an X-10 Mini Controller (Model MC460) or a Leviton Wall Controller (Cat. No. 16400) and would allow each controller to control its own set of 4 groups.
Line Access and Collisions
The unit waits for 9+(0-3) power line cycles clear of signal before commencing a transmission. For the REQUEST for OUTPUT STATUS message (xx01xxxx) (Hex 37) sent after any power up that results in memory loss, the access time is doubled to allow time for the internal power supply to fully stabilize. The (0-3) randomizer is calculated from the Housecode/Unit Code setting, the OUTPUT STATUS and the particular message requiring a response. It is not truly random in that the same message to the same Housecode/Unit Code for a unit with a particular OUTPUT STATUS will always result in the same Access Time. If there is interference on the AC line due to genuine X-10 messages, the Line Access procedure always applies. After access is achieved, during the transmission of Zero bits the unit performs Collision Detection and aborts that transmission attempt if a collision occurs. Subsequent attempts are made using the Line Access procedure. If the interference is not genuine X-10 codes, after 256 power line cycles the unit times out its Noise Wait and transmits with Line Access and Collision Detection bypassed.
The LM14A is rated for incandescent lamps only, up to 300 watts.
Appliance Modules, AM14A - 2 pin polarized and AM15A - 3 pin grounded
The operation is essentially the same as the Lamp Module, but with the difference that the Output Status is either Zero or Non-Zero and bit 6 of the Data Byte of the OUTPUT STATUS message (Hex 38) is set to '1'.
Other differences are:
- A: Bit 7 of the Data Byte is set to '1' if the Relay is open and the Load is connected, or if the Relay is closed. It is obviously not possible to test the state of the load when the relay is closed.
- B: There is no response to the STANDARD X-10 messages BRIGHT, DIM, ALL LIGHTS ON, and ALL LIGHTS OFF.
In the Auto-acknowledge mode, the unit doesn't answer back until the relay has achieved its intended state.
The AM14A and AM15A are rated at:
- 15A resistive (for coffee pots, electric blankets, etc).
- 1/3 HP for motors, etc.
- 500W for incandescent lamps (because of the inrush current from a cold lamp)
- 400W UL TV rating.
The content & opinions in this article are the author’s and do not necessarily represent the views of HomeToys
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