Watchdog II Mesh User Manual
P/N 86-0006-00
Rev E 01-2020
Page
5 of 38
General Introduction
The Pipeline
WatchdogCP ‘Mesh’ RMU is designed to measure, monitor, and report the output of
cathodic protection rectifiers and other sensor and transducer devices. Monitored data is:
Compared to programmable alarm limits for exception alarm reporting
Transmitted to the Elecsys Pipeline Watchdog Web Monitor database for viewing and reporting
Elecsys’ Pipeline Watchdog Website allows the user to:
Set up e-mail and text message alarms
Set up regular emailed CP rectifier and test station data reports
Obtain on-demand data reports
Change alarm limit parameters, reporting frequency and monitoring frequency over the air
1.1 Wireless Sensor Measurement Modules
The Watchdog II system uses wireless, battery-powered 3-channel sensor modules (Smart Nodes) that
are easily installed to measure voltage, current, and potential. The sensor modules are periodically
‘pinged’ by the Base Station to request data measurements.
The Watchdog II Base Station can monitor up to sixteen (16) channels (5 Smart Nodes), each of which
can be located up to 150 feet (45 meters) from the Base Station with an unobstructed line-of-sight. The
sensors can typically be read from the Base Station at a range of 50 feet through a rectifier housing or
building walls.
These wireless sensors represent a major development in the field of CP rectifier monitoring, where
lightning damage has long been a nemesis.
Elecsys’ wireless sensors are electrically isolated from
rectifier power or ground, and are simply connected across the rectifier output or across the rectifier
shunt in the same manner that one would connect a hand held voltmeter. They are protected against
high voltage transients and do not provide a low impedance path to ground for lightning current.
Each Smart Node is powered by a 4 NiMH rechargeable batteries that should last in excess of 3 years
under normal operating conditions. Replacement batteries are available from Elecsys as well as many
battery specialty companies (Batteries Plus, etc.).
The batteries are easily replaced in the field.
1.2 Watchdog II Base Station Wired Sensor Inputs
1.2.1
Dry Contact Digital Inputs
The Watchdog II Base Station has the ability to monitor up to four dry contact digital inputs (Pins 1
– 4,
with pin 9 as a common). The open/closed contact to be monitored should be wired to any one of the
four inputs and the Base Station common reference (pin 9).
1.2.2
Open Collector Digital Output
The Watchdog Base Station also has a digital output (J2, pins 5 and 9) that can be used to turn on and
off various devices. Pin 5 can sink up to 115 mA. The digital output can be linked to any or all of the
