110
SD Series Ref. Manual (Packet & Transparent Mode)
MDS 05-4846A01, Rev. C
8.5 Implementing Sleep Mode
Sleep Mode places the transceiver into a “hibernating” low power state,
with a nominal current draw of less than 10 mA (at 13 Vdc) and a
“wake-up” time of approximately 75 milliseconds. Sleep Mode is often
used at battery/solar-powered sites to conserve power.
The ability to enter Sleep Mode is controlled through the Device Set-
tings Menu (see “Enabling/Disabling Sleep Mode” on Page 52), but an
active low on Pin 4 of the
COM2
port is what actually puts the radio to
sleep.
How Sleep Mode
Works
When Sleep Mode is enabled via the Device Settings Menu, the state of
Pin 4 on
COM2
is continuously monitored to detect a request to enter
sleep mode from an external device (RTU, PLC, etc.). For ease of use,
there are certain conditions which temporarily override the sleep request
to prevent unwanted behavior of the radio. These conditions are:
1. The radio must be powered up for at least 60 seconds before it is
allowed to enter sleep mode.
2. Any user-originated activity on the console terminal disables
entering sleep mode for 30 seconds, measured from the time of last
keystroke.
3. When locally reprogramming the transceiver’s firmware, sleep
mode is disabled throughout the reprogramming time, and is sup-
pressed for 30 seconds thereafter.
4. The passage of payload data does
not
inhibit sleep mode.
Sleep Mode Example
This section describes how to implement Sleep Mode in a typical sce-
nario. Before using Sleep Mode, the following conditions must be met
to provide proper operation and avoid damage to the transceiver:
a. Sleep Mode must be enabled on the radio’s Device Settings
Menu.
b. Output voltage to the radio must not 5.0 Vdc.
c. Output voltage to wake up the radio must be b2.0 Vdc
and +5.0 Vdc.
d. Output voltage to enter Sleep Mode must be +0.6 Vdc or less.
With the above conditions met, you are ready to use Sleep Mode. As a
working example, suppose you need communication to each Remote
site in your network only once per hour. Program the RTU/PLC at the
Remote sites to raise an RS-232 line once each hour (DTR for example),