GASMAX ECx Instruction Manual
Revision 1.1
6
2.2.2 “Radio Awake” Control Timing and Conserving Battery Life
Most GM ECx battery power is consumed as the radio communicates to the wireless network.
Each communications cycle consists of the following sequence: Wake the radio in receive mode;
listen for the Server’s beacon; synchronize to the Server’s hopping frequency; transmit data
packet, return to sleep mode. This sequence takes between 0.25 to 1 second to complete.
Transmit power levels are adjustable; lower power setting will result i longer the battery life.
Every six seconds, the monitor performs a “sniff test” to detect level of target gas present at the
sensor. At each “sniff test”, the
Zzz
’s RS icon is briefly replaced by “Server In Range” or “Server
Out of Range” icon and the readout is updated to indicate the current gas value. The radio
remains in sleep mode if the gas value does not trip either the A1 or A2 alarm. Upon each 50
th
consecutive “sniff test” (every 5-minutes) the radio wakes up, receives the Server’s beacon, and
transmits the latest gas data. These 5-minute transmissions ensure that all controllers can
monitor the wireless communications link even when no alarms exist. If A1 or A2 alarms do exist
during the “sniff test”, the radio wakes, receives the Server’s beacon, and transmits its data
immediately.
The following list identifies each of the conditions that cause the radio to transmit:
•
Five minutes, or fifty sequential reads (when there is no A1 or A2 alarm). Any receiving
controller will report a “Communications Error” if the GM ECx does not reply for periods of
greater than 18-minutes. A3 and FAIL alarms do not increase radio transmission rates.
•
Every six seconds, if there is an A1 or A2 level alarm.
•
Upon entry into CAL mode a value of 75 (-15.6% scale) is transmitted. Controllers so
programmed will indicate “IN CAL” when this occurs.
•
Upon entry into CAL PURGE mode a value of 200 (0% scale) is transmitted.
NOTE: Oxygen sensors transmit a value of 20.9% upon entry into CAL PURGE mode.
•
Holding the magnet over the UP key for >10seconds forces a transmission of the current
reading value.
2.2.3 GM ECx BATTERY # 10-0293
GM ECx electronics consists of the lower 10-0299/Battery I/O PCB (Figure 2-2) connected by a
cable to the upper Display assembly with 10-0291 RF Module PCB (Figure 2-3). The 10-0293
3.6 volt lithium ‘D’ cell battery will continuously power the unit for up to one year and may be
replaced by following the procedure in Figure 2-2.
Power switch (SW1), on the 10-0299 Battery PCB, applies battery power to the GM ECx monitor.
SW1 should be OFF if the monitor is to be out of service for long periods.
IMPORTANT:
Do not turn SW1 ON until the controller designated as Server is fully operational
and ready to communicate to the GM ECx. Battery life is reduced if the GM ECx is on for long
periods while unable to communicate to the Server controller.
IMPORTANT:
DO NOT ATTEMPT TO CHARGE THIS BATTERY OR REPLACE WITH ANY
OTHER THAN PART #10-0293 FROM GDS CORP.