Tyco MX4428 - Manual (Page 13)

Document: LT0273 MX4428 MXP Engineering / Technical Manual
Responder Loop Design Considerations
Issue 1.5 24 March 2006 Page 2-3
2.2 "LOGICAL" RESPONDERS
2.2.1 THEORY
The MX4428 Master Panel can transfer data to and from up to 127 uniquely addressed
Responders distributed around the MX4428 Responder Loop. Its database is structured to
support the 4 circuit inputs and 4 relay outputs associated with the most common responder
type, the ADR. Incorporating an MXP, which supports up to 200 input, output, or input /
output points, represents a departure from the original ADR / AAR structure, but it is similar
to that used for the MPR multiprotocol responder.
To incorporate the MXP, while still preserving the original 1 x MX4428 LOOP ADDRESS
SUPPORTS 4 INPUTS (“CIRCUITS”) AND 4 OUTPUTS (“RELAYS”) database assumption,
the concept of "logical responders" is used. A logical responder refers to a single responder
loop number, supporting 4 inputs and 4 outputs. An ADR/ARR therefore represents a single
logical responder. A responder that supports more than 4 inputs and outputs, such as the
MXP, must therefore occupy multiple responder loop numbers. That is, it is a "multiple
logical responder" unit. One MXP may in fact be configured at the MX4428 FIP to be
between 1 and 50 logical responders.
Since an MXP can support up to 200 points irrespective of how many logical responders it
has been configured to represent, it may be necessary to allocate multiple points to each
logical responder circuit input or relay output. This has certain implications described below,
the most significant being that it is a logical responder “circuit” which is mapped to a zone,
not a point, and it is a logical responder “relay” which is mapped to an ACZ, not a single
output point. Thus if multiple devices are allocated to a circuit, they must all be in the same
zone, and if multiple outputs are allocated to a relay, they will generally be controlled as one.
2.2.2 LOGICAL RESPONDERS
Points map to logical responder circuits and relays as shown in Table 2-1 for different
numbers of logical responders.
Basically the 200 points are evenly distributed across the number of logical responder
circuits/relays (= number of logical responders * 4), with the remainder allocated to the last
circuit.
Input devices are map to the circuit. Output devices usually map to the relay, but may map to
the circuit by programming.
The 50 logical responder option is the only one that allows unique monitoring and full front
panel indication of all 200 individual points without using the MX4428 Point Text expansion
option. The 50 logical responder option however, uses 50 of the 127 available MX4428
responder loop addresses and therefore limits the remainder of the MX4428 system.
Figure 2.1 shows an example 3 logical responder MXP, which has a capability of 3 X 4 = 12
circuits (C1/1-1/4, C2/1-2/4, C3/1-3/4) and 12 relays (R1/1-1/4 ..... R3/4).
Splitting up the possible 200 addressable devices equally among the 12 circuits results in
each circuit being able to service 200/12 = 16 devices, with 8 left over. Thus devices 1-16
are associated with circuit C1/1, devices 17-32 are associated with C1/2, etc, up to C3/4,
which not only handles its own 16 points but also the extra 8 device addresses (193-200)
otherwise not catered for. Input devices are mapped to circuits, and output devices are
usually mapped to relays but may alternatively be mapped to the circuit.