Honeywell W7750A specifications Broadcasting the Service Message, W7750 Controller Status LED

EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER

Table 12. Excel 10 Alarms. (Continued)

	Alarm type
Name of alarm or error bit	number	Meaning of alarm code or error bit
LOSS_OF_AIR_FLOW	6	The Fan Status DI indicates that there is no air flow when the node is
		commanding the fan to run. The control is shut down and disabled until power is
		cycled or the node is reset. See NOTE below. The alarm is not issued until
		FanFailTime seconds have elapsed since the loss-of-flow condition was first
		reported
DIRTY_FILTER	7	The pressure drop across the filter exceeds the limit and the filter requires
		maintenance. The control runs normally.
SMOKE_ALARM	8	The smoke detector has detected smoke and the node has entered an
		emergency state.
IAQ_OVERRIDE	9	The indoor air quality sensor has detected that the indoor air quality is less than
		the desired standard and additional outdoor air is being brought into the
		conditioned space.
LOW_LIM_ECON_CLOSE	10	The economizer has to close beyond the minimum position to prevent the
		discharge air temperature from going below the discharge temperature low limit.

NOTE: The node can be reset by switching the node to MANUAL and then to the normal operating mode (see Fan Operation in Appendix B).

Also, the Excel 10 variables, AlarmLogX where X is 1 through 5, that store the last five alarms to occur in the controller, are available. These points can be viewed through XBS or E-Vision.

Certain alarm conditions are suppressed conditionally as follows:

Broadcasting the Service Message

The Service Message allows a device on the LONWORKS Bus to be positively identified. The Service Message contains the controller ID number and, therefore, can be used to confirm the physical location of a particular Excel 10 in a building.

There are three methods of broadcasting the Service Message from an Excel 10 W7750 Controller. One uses a hardware service pin button on the side of the controller (see Fig. 41). The second uses the wall module pushbutton (see Fig. 43 and 44). By pressing the wall module pushbutton for more than four seconds, the controller sends out the Service Message. The third involves using the PC Configuration tool, as follows.

When an Assign ID command is issued from the commissioning tool, the node goes into the SERVICE_MESSAGE mode for five minutes. In the SERVICE_MESSAGE mode, pressing the Occupancy Override button on the remote wall module (refer to Fig. 43 and 44 for override button location) causes the Service Message to be broadcast on the network. All other functions are normal in the SERVICE_MESSAGE mode. Even if an Excel 10 W7750 Controller does not have an Override button connected, it can broadcast the Service Message on the network by temporarily shorting the Controller Bypass Input terminal to the Sensor Ground terminal on the W7750A,B,C (short terminals 3 and 5).

The commissioning tool is used to perform the ID Assignment task (see the E-Vision User’s Guide, form 74-2588).

SERVICE

PIN

BUTTON

M10094

Fig. 41. Location of the Service Pin Button.

W7750 Controller Status LED

The LED on the front and center of a W7750 Controller provides a visual indication of the status of the device. See Fig. 42. When the W7750 receives power, the LED should appear in one of the following allowable states:

1.Off— no power to the processor.

2.Continuously On— processor is in initialized state.

3.Slow Blink— controlling, normal state.

4.Fast Blink— when the Excel 10 has an alarm condition.

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