At a Glance

  • Detect Power Supply Out-of-Tolerance
  • Detect Loss of Control in Machine Automation
  • Optimized for PLCs, Single Board Computers and Distributed Control Systems
  • Ideal for Mission-Critical Controls
  • "Double Redundant" Design
  • Industrial Rugged: -40 to +85 deg. C.
  • 3 Year Limited Factory Warranty
  • 3-30 VDC Opto-Isolated Input
  • PLC Sinking or Sourcing Logic
  • Base Configuration 5-28VDC No Supervision
  • Fast/Slow Input LED
  • 5, 12, 24 VDC Supply Voltage Supervision
  • “First-Fault” lock-out
  • 90-132VAC/60Hz  Power Line Monitoring
  • Power-up Trigger
  • Dual-Edge Triggering
  • Customize It! IPD is glad to quote your specific custom module


The P8D-ISM Industrial Supervisory Module is a high-performance fault monitoring system for today’s sophisticated industrial control systems, especially Machine Controls and Robot Controls.  It combines a voltage-reference based Power Supply Voltage Monitor with a feature-rich, fully-digital Watchdog Timer.  This evolution of Brentek’s field-proven P8-WDT24/PLC Watchdog Timer gives engineers an entirely new level of monitoring performance for their mission-critical and safety-critical control systems.   If the control system is mission critical or if individuals’ safety depends on the control system either working properly or shutting down safely, then it is essential that the system’s designers implement proper monitoring and appropriate fault reaction protocols.

Because power supply voltage issues can lead to system faults, continuous verification that Vcc is within tolerance is an important consideration in controller fault prediction and detection strategies.  Drop-outs, brown-outs, spikes, and surges can weaken controllers making them prone to failure.  Brown-outs, spikes, and surges can lead to ambiguous controller and peripheral states that can take the system “into the weeds” in a way that is virtually impossible to adequately test for during system qualification.  By monitoring for these voltage conditions and using the Supervisory Module’s output to trigger appropriate system reactions, the undesirable/intolerable effects of voltage fluctuation issues can be mitigated. 

The P8D-ISM’s watchdog timer is used to monitor the control system’s digital “heartbeat” signal.  When the signal stops toggling, it indicates “Loss of Control” which could be caused by any of a multitude of unpredictable conditions such as peripheral failures, unanticipated/untested software states, voltage spikes/droops, unauthorized tampering with the system or controls, connector/wiring issues, etc.   No matter how robust the design and implementation of a control system is, unless it has a watchdog, it is still subject to lockups due any of these faults – and the causes are entirely beyond the designer’s control! 

The P8D-ISM Industrial Supervisory Module monitors controller-health using voltage and timing conditions - making sure that its output is energized only when all supervised conditions are satisfied.  The P8D-ISM Industrial Supervisory Module provides the features and capabilities that can be used to provide fault prediction, detection, and protection for Programmable Logic Controllers (PLCs), One-board Controllers, and Distributed Control Systems by providing high-reliability, ease of integration, and a deep range of capabilities. 

High Reliability  The P8D-ISM’s watchdog timer has a “double-redundant” design that uses a combination of proven technologies to supervise it's own integrity as well as that of the monitored system, providing the highest level of control system integrity.  The design includes adaptive triggering to avoid re-triggering on any spurious back-EMF signals that might occur when the module “alarms”.   The fully-encapsulated circuitry and industrial operating temperature rating make the P8D-Series well suited to robust industrial applications.

Ease-of-Integration  Its compact low-profile package makes it easy to integrate onto panels or DIN rails using industry-standard Octal Relay Sockets such as the Brentek DIN8.  The 5, 12, and 24 VDC supply voltage offering covers all standard industrial controls voltages.  The input is optically-isolated and can accept 3 - 30 VDC trigger pulses from either Sourcing Logic or Sinking Logic.  Its SPDT FORM C dry contact output is rated for 8 Amps@ 30VDC/250VAC allowing it to directly control most loads –even contactors!  

Deep Range of Capabilities  A host of sophisticated configuration features include fixed time-outs from 50 milliseconds to 60 seconds, user-specified adjustable timing ranges , a “first-fault” lock-out function requiring a user reset after a system fault occurs, quantitative LED indication of input pulses and voltage faults, enhanced trigger tolerance for inductive load “spikes”, 90-132VAC/60Hz line monitoring, plus others.

The P8D-ISM Watchdog Timer from Brentek is the solution to monitoring today’s ultra-sophisticated mission-critical control systems.  For further information, see the P8D-ISM Datasheet.  If you would like to discuss your application with an engineer, please contact us and we will be happy to help. 

How to Purchase Customize It!