INNOVATIVE PRODUCTS > APPLICATION NOTES
SSRMON APPLICATION NOTE AN1
This application note using the SSRMON in a single phase system provides:
- Alarm if the solid state relay becomes shorted
- Alarm if the process load opens
- Alarm if the process load loses power
- Power for the SSRMON’s internal circuitry
- Monitoring of the process controller power supply and power source
- Monitoring of the alarm output from process controller
FIG. 1 shows an application where the NuWave Technologies SSRMON is used to detect multiple failure modes of a typical control system. The Process Controller is setup with a heat or cool output (1) and an alarm output (2). The heat or cool output (1) is setup as a time proportioned PID output with a logic drive signal for the SSR and SSRMON. The Alarm output (2) is setup as a process alarm (high, low, deviation, etc.) such that when the process value is normal, the logic alarm output (2) is high. The logic alarm output (2) powers the SSRMON’s internal circuitry.
If the controller loses AC line power or if it’s power supply fails, the logic alarm output (2) goes low and the SSRMON’s output relay immediately opens signaling an alarm condition. If the controller produces a process alarm on output 2, the SSRMON loses power and it’s output relay immediately opens signaling an alarm condition. If the SSRMON detects a Shorted Solid State Relay, Open Load, or Loss of load power, it’s output relay immediately opens signaling an alarm condition.
 |
|---|
| Figure 1 |
