Trane Engineered Smoke Control System for Tracer Summit, BAS-APG001-EN manual Custom bindings

Custom bindings

Custom bindings

A distinction is made between FSCP and mechanical system control in this section. While smoke control panel processing is predictable, mechanical system processing (actuators, feedback validation) is unknown. It is limited to approximately five smoke control zones based on the UUKL-approved smoke control panel. Because the number and application of each MP581 and EX2 modules is unknown, the mechanical system will be represented as a “cloud.”

The recommended smoke control system design is to have one MP580/581 assigned as the “communication clearing house” or hub. It may be necessary to use two or more hubs, one for panel control and another hub(s) for the mechanical system. This design will simplify the binding creation process and makes the system more scalable. For more information regarding the limitations placed on custom binding and recommendations regarding custom binding design, see “Understanding bindings” on page 130.

The bindings and variables shown in Table 31–Table 37 were those used in the tested UUKL system to send information between MP580s. The system programmer can use whatever bindings and variables are necessary.

UUKL binding list (watchdog communication)

“Trouble signals and their restoration to normal shall be annunciated within 200 seconds of the occurrence of the adverse condition, fault, or the restoration to normal.” (UL-864: 49.2.b)

As there is no built in means of verifying inter-MP581 communication status, a programmed solution must be used. While a network variable “heartbeat” can be used to verify status, it can take up to 300 seconds for a communication failure to be noticed. This solution would fail to meet the requirement given in previous paragraph. The tested solution is based on a “watchdog” style where a continuously changing network variable triggers a timer every time it changes state. As long as the timer never expires, it is assumed that the two devices are communicating. In this fashion, a communication failure can be annunciated within 60 seconds.

Table 31 on page 124 shows an example of a custom binding list. One group binding binds MP580-2, which is the hub, to all other MP581s (for an explanation of group bindings, see “Understanding bindings” on page 130). The “watchdog” signal sent to the group is used by each receiver to confirm communications from the hub unit. The hub unit is able to validate communications from each of other MP581s using their individual “watchdog” signals. These bindings are point-to-point based. There may be two hubs in the system, one used with the FSCP and other within the mechanical system. The need for a second hub will be driven by the size of the mechanical system involved. Figure 71 on page 125 illustrates watchdog communication between MP581s in a hub-based system.

BAS-APG001-EN 123