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What is PV-Safe, and How do I Re-Activate my Legacy System?

  • Updated

This article discusses the basics of PV-Safe and re-activation on Tigo Legacy systems. 

Contents: 

For information on modern TS4 Flex Manual PV-Off Functionality click Here.

 

mceclip0.pngPV-Safe Overview

All Tigo Systems offer a PV-Safe function that manually (or automatically) disarms a system at the Optimizer (or panel) level.

  • Manual - DC shut-off at the PV-Module level, to encourage safe working conditions.
  • Automatic - DC shut-off for systems experiencing over-current or over-voltage events.

Classic Tigo systems that incorporate the original MMU or Cloud Connect, offer a PV-Safe command which completely de-energizes the PV Modules (solar panels), so that the DC portion of the system is safe to work on. After the work has been completed, the system can be re-energized.

 

PV-Safe Activation

To activate this function, simply press the large red PV-Safe button on the face of the device: 

 

Tigo MMU – Solacity Inc. – Solacity Inc.Cloud Connect/MMU Menu Reference – Tigo Help Center

 

If all of the MLPE's are in working order (and communicating), this action will de-energize them, within 30 seconds.

Note: PV-Safe is a manual command that must be deployed locally. Tigo Support Agents do not have the capability of enabling or disabling the command, remotely. 

 

Safety Precautions

Please be aware that the PV-Safe command operates on wireless (radio) communication. If the system has units that are not communicating or the data line (to the Gateway) is damaged, the affected modules may continue to transfer voltage to the string. For this reason, it is important to review the online data to make sure that all units are communicating (before working on the system), and take the necessary precautions if there are units that are not communicating.

If you do not have access to the system's data or require general guidance/information, you may contact Tigo Support for assistance.

Note: PV-Safe is for safety control of the production on the DC-Side, only. This does not affect Grid controls, lines or breakers on the AC-Side. Please take all necessary precautions to insure a safe work environment for yourself and others. 

 

Re-Energize (deactivate PV-Safe)

Once you have completed your task(s) and are absolutely sure that there are no other people working  on the system, you may take the steps to re-energize. To do this, you must follow the Menu options to deactivate PV-Safe command (within the Menu on the Data Logger):

  1. Press Menu (press enter)
  2. Press the Arrow up or down to navigate to: 2.Control (press enter)
  3. Press the Arrow up or down to navigate to: 2.2Modules On (press enter)
  4. Screen display says "Are you sure?" (press enter)

 

After performing these steps, the DC portion of the system will re-energize to it's full output and the inverter should start up within a few minutes.

 

Adding a Push Button Safety Switch (for PV-Off)

Tigo's legacy Data Loggers have their own built-in PV-Safe button, located on the face of the device. However, you can add your own PV-Off manual latching push button, safety switch, or relay.

 

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  • Operation mode: Normally Open (NO) button. In most cases, NO or NC operation can be configured within the switch housing
  • Latching mechanism: Button must have latching mechanism (twist to release, key lock, etc.)

The form factor of the MMU and Cloud Connect are very different, but the wiring process is similar. The Accessory Terminals are located in different areas: 

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An external latch, button, switch or relay can be wired to the + & - connectors on the Accessory Terminal. When the switch is Open, the PV-Off will not be activated and left side terminal will have 3.3 VDC (good to know for troubleshooting wires/cables).

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How to Wire Multiple Data Loggers to a single Shut-off Button

Up to 5 data loggers can be connected to a single switch.

For a shutoff button to work on multiple data loggers, each logger must be connected to the shutoff button on its own individual wires that run point to point from the switch, not daisy-chained in parallel.

  • Be sure to connect the right hand side terminals, and the left hand (3.3 VDC) wires together, as shown in the diagram below.
  • No outside-source voltage MAY EVER be placed on the AUX port (voids Warranty)
  • The ground of the system should be connected to the 24 VDC "-" Negative terminal
  • The left-hand pin should read close to 3.3 VDC when the switch is OPEN. 0 VDC when the switch is CLOSED (activated)
  • When connecting multiple Data Loggers to the same switch be sure that the maximum distance between the shut-off button and the first Data Logger is under 100 meters.
  • Additional Data Loggers also must be less than 100 meters apart from each other

 

 

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Video Presentation

This video illustrates PV-Off feature (at Min 1:32), as well as how to restore power:

 

 

 

Further Resources

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