Bullhorn Model RM4150 / RM4151 Remote Monitor by American Innovations

Mounts In or Outside of Rectifier. Monitors Rectifiers, Well Casings, Tanks, and Other C.P. Assets


3G/4G cellular-based, reliable, two-way wireless remote monitoring unit (RMU) for cathodic protection applications that is Built Bullhorn Tough. They monitor pipelines, well casings, tanks and other assets by reading rectifier AC and DC volts and amps, pipe-to-soil potential, shunts, and more. The RM4150/RM4151 is extremely accurate, measuring AC and DC voltage with 1 percent of reading accuracy all of the way through the range.

The RM4150 and RM4151 remotely collect cathodic protection (CP) measurements used to demonstrate corrosion mitigation effectiveness. They monitor pipelines, well casings, tanks and other assets by reading rectifier AC and DC volts and amps, pipe-to-soil potential, shunts, Instant Off, line power presence and more. The digital channels provide an accumulator for metering applications and, with an optional accessory, intrusion detection. Via 3G/4G cellular networks, measurements are automatically uploaded to Bullhorn Web, a web-based asset manager that works with PCS™ to form a full end-to-end regulatory compliance solution from field measurement to reporting. The RM4150 received a Materials Performance magazine 2014 Corrosion Innovation of the Year Award.

Key Benefits

  • Rugged – The unit can survive the harshest of conditions, with built in surge protection and optional high energy surge arrester.
  • Accurate – AC and DC voltage with 1 percent of reading accuracy all of the way through the range. For example, a 1mV measurement will be accurate within +/- 10 microvolts. Every measurement is automatically calibrated and zeroed. Find and fix small problems before they can become big ones.
  • Remotely Operated via the Web and Mobile – Never have to leave the office to operate a unit, as the mobile and web apps can be used to change configuration, take a measurement, control interruption, and initiate instant off readings.
  • Integrated Compliance Solution – Complete end-to-end system to prove regulatory compliance, with filtered measurements easily imported into PCS where they can be made into compliance reports.


Feature Benefit
Analog channels measure both AC and DC Potentials Single unit to measure rectifier volts and amps, pipe-to-soil potential, shunts, Instant Off and more
One percent of reading accuracy Extremely accurate current and voltage measurements
Digital channels provide discrete/close contact inputs and accumulator functionality The unit can also be used for intrusion detection, threshold detection and other state changes as well as pulse counting for metering
10 MΩ impedance Improved pipe-to-soil accuracy where just a few mA can be the difference between being in compliance and not
Pipeline Compliance System (PCS) integration Import RMU data directly or file transfer using Bullhorn Web
Compatible with global cellular networks Quickly communicate anywhere in the world where digital cellular network coverage is available.
Two-way communication Within seconds poll, reconfigure, modify reporting schedules, set alarm thresholds and update firmware over-the-air
Sends alarms based on specific events (e.g. reading out of range, power loss, intrusion detection, etc.) Receive unlimited notifications via text message, email, and voice
Configurable over-the-air via Bullhorn Web or locally via USB
  • Configure remotely from the office or on-site
  • Save configuration settings and load to multiple units
Built-in GPS synchronized interruption
  • Save time conducting rectifier influence studies and close interval, depolarization, and DCVG surveys
  • Measure Instant Off pipe-to-soil potentials from individual rectifiers
  • Generate an alert if interruption fails
Unique Interference Mode interruption for influence studies is compatible with the RM4010, RM4011, RM4151, MicroMax GPS300, and GPS350 interrupter
  • Improve accuracy of rectifier influence studies
  • Reduce time and costs
Bullhorn Web system communicates unit status by email, text, or web notifications
  • Eliminate remote site visits with equipment status notifications
  • Get on-the-go access via smartphone
Internal backup battery Receive alarms when power fails
More than 6.6 kV built-in surge protection per IEC 61000-4-5 specification Increase product reliability with immunity to lightning and other surges


5 Analog Channels
DC voltage range: +/-150 V
AC voltage range: 150 V
Input impedance: 10MΩ
Accuracy of 1% of reading
Scan rate: once every 30 seconds
Channel-to-channel isolation: ≥ 250 V DC
2 Digital Channels
Functions: digital input, accumulator, accumulator reset, or contact closure (0 - 24 V DC)
Logic levels: minimum Logic 1 = 2 V; maximum Logic 0 = 1 V
Scan rate: 20 scans per second
Accumulator maximum cycle rate = 1 cycle/2 s; minimum state change period = 1 s
Minimum pulse width: 250 ms


Interruption Option
Maximum current: 500 mA DC
Output voltage: 10 – 14 V DC
Minimum switching cycle: 1 s
On/off cycle increments: 100 ms
Interruption modes: daily, interference, start/stop, continuous, and Instant Off
Interference mode: set up to 99 rectifiers or groups for influence studies
Relay types: NO or NC, solid state or mechanical


Instant Off
Analog channel 3: ± 10 V DC, sampled 60 times per second
IR drop edge delay: 0 to 60 seconds in increments of 1 ms
Configuration: GPS-synchronized measurement using configurable On, Off, and delay settings


Worldwide compatibility on 2G/3G/HSPA/4G GSM networks
Carrier independent. Automatically selects the best signal
Poll, reconfigure, and set alarm thresholds over-the-air


  Software Interface  
Bullhorn Web
Bullhorn Tools for PC


Power Supply
AC: 100 - 240 V AC with included AC/DC converter
DC: 10 - 14 V DC with interruption; 5-25 V DC without interruption
Backup: internal sealed rechargeable battery


Internal mount: polycarbonate enclosure (7.9” x 5.0” x 2.2”)
External mount: NEMA 4X compliant enclosure (4.0” x 7.3” x 12.4”)


Data Integrity
Data stored in non-volatile (EEPROM) memory.


Temperature: -30° C to +70° C
Humidity: 0 - 100% non-condensing


FCC part 15
NEMA 4X compliant enclosure
ESD: 8kV Air / 4 kV Contact