2
796-20
Note:
Because the 730-00 Smart Pad keypads are not IR receivers, this restriction does not apply
to them. They may be added virtually without limit, provided power supply requirements are taken into
consideration. See item 3 below.
2. Be sure to connect the
+12V
, OUTput and Gnd of each IR receiver and keypad to the resp
12
,
IN
and
G
terminals of the zone inputs as shown.
3.
Power Supply Requirements.
In elaborate installations you may combine many Xantech keypads,
IR receivers, controllers and emitters in a system. Having sufficient power supply voltage and current
available can be critical to achieve proper operation. To be sure you have adequate power supply
capability, take the following factors into consideration:
a) The maximum current available from a 781RG Power Supply for proper operation is 200 mA
(milliamps).
b) The maximum current from a 782-00 Power Supply is 1000 mA.
c) Most IR receivers draw 2 mA without signal and 10 mA with signal. Refer to the IR receiver's spec's
for actual value.
d) Each 730-00 keypad draws 7 mA without signal and 65 mA with signal. The SmartPad
2
draws 85
mA, with or without signal.
e) Each emitter connected to the Zone and Common Ports of the 796-20 draws 3 mA with signal and
0 mA without.
f) Add 10 mA for each Xantech powered accessory, such as the 794/797 Interface modules, 791-44
Amplified Connecting Blocks, etc., if they are powered from the 796-20.
g) When using combinations of these devices, add up the currents as shown in the following example.
Then choose a power supply that has a maximum available current that is higher than the total
current required.
For example, the power supply needed for the system shown in
Fig. 2
is arrived at as follows:
h) The no signal current for the 6 IR receivers is 6 x 2 = 12 mA.
i) The current for the SmartPad
2
is = 85mA.
Note: Since only one IR device normally operates at any given time, only one IR device, the one
with the highest current, needs to have its "with signal" current included (in this case, the SmartPad
keypad).
j) The current for one 794-60 Interface module = 10 mA.
k) The current for one 791-44 Amplified Connecting Block = 10 mA.
l) The current for 7 emitters at the 791-44 ports is 7 x 3 = 21 mA.
m) The current for the emitters at the Zone ports is 2 x 3 = 6 mA. (Since all the zone emitters cannot
operate the zone equipment at the same instant in time, only one zone is included. In this case we
chose zone 5 (or 6), since one emitter and a device are driven ).
n) Now add up all the currents from steps h) through n).
12 mA + 85 mA + 10 mA + 10 mA + 21 mA+ 6 mA = 144 mA total. Since this is wqell below 200
mA, one 78RG power supply would suffice.
If the total current exceeds 200 mA, simply step up to the 782-00 power supply.
NOTE: To avoid current "hogging", never connect regulated supplies (such as the 781RG and the
782-00) in parallel.
CAUTION: Do not use unregulated 12V power supply adapters from other manufacturers.
These may deliver excessive voltage to the IR receivers and cause them to “latch-up”. When this
occurs, the “talkback” LEDs in the IR receivers and on the 796-20 Zone Controller may stay on
continuously!
