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EXCEL 10 W7761A INPUT/OUTPUT DEVICE
12 74-2699
CPU:
Motorola or Toshiba 3150 Neuron
processor, containing three eight-bit CPU’s. Each Neuron
has a unique 48-bit network
identification number.
Memory Capacity:
64K ROM/PROM (6K reserved for network operations, 58K usable for control algorithm code).
512 bytes EEPROM.
2K RAM.
Specified Space Temperature Sensing Range:
45 to 99°F (7 to 37°C) with an allowable control setpoint range from 50 to 90°F (10 to 32°C) when initiated from the network
and 55 to 85°F (13 to 29°C) when configured and connected to T7770 Wall Modules or T7780 DDWM.
Communications:
The W7761A Device uses a transformer-coupled communications port with differential Manchester-encoded data at 78 kilobits
per second (kbs). The transformer-coupled communications interface offers a much higher degree of common-mode noise
rejection while ensuring dc isolation.
Approved cable types for E-Bus communications wiring is Level IV 22 AWG (0.34 mm
2
) plenum or non-plenum rated
unshielded, twisted pair, solid conductor wire. For non-plenum areas, use Level IV 22 AWG (0.34 mm
2
) such as U.S. part
AK3781 (one pair) or U.S. part AK3782 (two pair). In plenum areas, use plenum-rated Level IV, 22 AWG (0.34 mm
2
) such as
U.S. part AK3791 (one pair) or U.S. part AK3792 (two pair). (See Tables 6 and 8 for part numbers.) Contact Echelon
Corp.
Technical Support for the recommended vendors of Echelon
approved cables.
The Free Topology Transceiver (FTT) supports polarity insensitive free topology wiring. This frees the system installer from the
need to wire using a bus topology. Star, bus, mixed, and loop wiring are all supported by this architecture. The maximum E-Bus
length when using a combination of star, loop, and bus wiring (singly terminated) is 1640 ft (500m) with the maximum node-to-
node length of 1312 ft (400m). In the event that the total wire length is exceeded, then a Q7740A 2-Way Repeater or a Q7740B
4-Way Repeater can be used to allow the number of devices to be spread out as well as increasing the length of wire over
which they communicate. The maximum number of repeaters per segment is one (on either side of the router). A Q7751A E-
Bus Router can also be used to effectively double the maximum E-Bus length. The advantage of using the router is that it will
segregate traffic to a segment while when using the repeater, all traffic is repeated on each segment. When utilizing a doubly
terminated E-Bus structure, use a continuous daisy-chain with no stubs or taps from the main backbone, The maximum E-Bus
length is 4593 ft (1400m) with the maximum node-to-node length of 3773 ft (1150m).
FTT networks are very flexible and convenient to install and maintain, but it is imperative to carefully plan the network layout
and create and maintain accurate documentation. Unknown or inaccurate wire run lengths, node-to-node distances, node
counts, total wire length, and misplaced or missing terminators can cause poor network performance. Refer to E-Bus Wiring
Guidelines form, 74-2865 for complete description of network topology rules.
LonMark Functional Profile
W7761A Device supports the LonMark
Preliminary Functional Profile for a Remote Input/Output Device.
Environmental:
Operating Temperature:
-40° to 150°F (-40° to 65.5°C).
Shipping Temperature:
-40° to 150°F (-40° to 65.5°C).
Relative Humidity:
5% to 95% noncondensing.
Vibration:
Rated V2 level compliant.
Inputs/Outputs:
The W7761A Unit supports the following hardware features:
• Four 20KNTC (1000 through 150,000 ohm) or PT3000 (250 through 12,000 ohm) resistive analog inputs.
• Two 0.2 to 10 VDC or 2 to 20 mA (user selectable) analog inputs.
• Four dry contact digital inputs.
• Eight 24 Vac Triac digital outputs (500 mA MAX).
• One 22 Vdc power supply for auxiliary devices with a maximum current of 50 mA.
Analog Inputs:
Space Temperature:
Type: RTD.