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M150 vs. M850
Generally, the M850 is more appropriate where analog sensors are present, at master lift
stations, and for remote control applications. Both RTUs provide real-time alarms. The
M150 accumulates pump starts each hour whereas the M850 reports real-time pump state
changes. The M850 reports analog values every two minutes or sooner (>5% change) for
trending purposes. The M150 supports up to three pump runtime inputs whereas the M850
supports up to eight.
Metal Oxide Varistor (MOV)
The included MOVs are used to protect circuits against high transient voltage spikes, often
caused when relay coils de-energize. They are rated for 150 volts. Voltage above 150 volts
will be dissipated. The MOVs are non-conductive during normal operation. Consult your
electrician before installing the MOVs.
Power and Backup Power
The M150 and M850 RTUs operate on 12 VAC via the supplied transformer. The 120 to 12
VAC transformer mounts outside the RTU to minimize the chances of induced voltages. A
five amp-hour battery with a charging circuit powers the RTU for 18–50 hours (M850 and
M150) during a power failure. AC power fail alarm will be dispatched. A low battery alert will
be dispatched in the morning if the battery voltage fell below 11.5 volts anytime the previous
day.
Pulse Inputs Options
Pulse inputs can be used to report data such as flow, water meter, or rainfall totals. If no
rainfall data is monitored at the site, Mission’s web site presents data from the closest
National Weather Service reporting station. Four pulse inputs are available with the Safe
Module Plus.
Radio Access Technology (RAT)
As cellular networks evolve, radios must be updated to the current RAT. See Long Term
Evolution (LTE).
Runtime Inputs
A digital input that is configured to calculate runtime minutes and pump starts each hour.
Alarm notifications are generally not enabled for runtime inputs.
SIM (Subscriber Identity Module)
This card carries an identification number that contains the billing credentials for certain
cellular radio. Removal of card will disable operation.
