Design Essentials for TS4-F/-A-F

Designing a system to meet rapid shutdown with TS4-F/TS4-A-F is easy 👌

How it Works:

When your RSS transmitter is powered on, the RSS core in each RSS transmitter sends a pulsed signal to the TS4-F/A-F units in the system over DC wiring. 

When your RSS transmitter is powered off, this signal disappears, and each TS4-F/A-F unit goes into shutdown mode, reducing voltage within the array to under 80V within 30 seconds.

How to Start Your Successful Design

1. Add one TS4-F/TS4-A-F to each module in your system, or one TS4-A-2F for every two modules.
2. Purchase RSS-integrated inverters from Tigo's Preferred Partners (such as the SMA Core1-41, Solectria PVI 50/60, Chint KTL 20/25/50/60, others) or use one RSS Transmitter Core for each 10 strings

 The TS4-A-2F adds safety features to two modules per unit.

Note on Odd Length Strings

If you are using the dual TS4-A-2F product with odd length strings (15, 17 modules, etc) the single TS4-A-F can be used in the same string with the TS4-A-2F.  Or, you can simply connect the leads from input #2 (right-hand inputs) together.  As with all TS4s, make sure all of the panel leads are connected before connecting the TS4 to the string.  For more details, see the TS4-F Installation Manual.

Design considerations for add-on Tigo RSS Transmitters

Powering your (external) RSS transmitter

Each Tigo external (add-on) RSS transmitter is powered via 12V DC input.

The RSS transmitter can ship from Tigo and its distributors with either a 120/240V AC power supply or 277/480V power supply. Choose what works best for your application. 

How many Tigo add-on RSS transmitters do I need? (for C&I projects)

See Tigo's "Product Selection Tool" for assistance

Design considerations for All Systems

How long can my DC loop for each string be?

The entire DC loop for each string, from the positive terminal on the inverter, out through the array, to the negative terminal on the inverter, can be up to 1000 feet (300 meters).

CONTINUITY REQUIRED NOTE: RSS Transmitters need DC string-loop continuity to enable the signal to propagate correctly over the string cables to reach the TS4-F units.  This usually means that the home runs need to be connected to the inverter.  The inverter may also need to be powered-on for proper signal propagation through-out the loop.

Special note for SMA inverters

All of the SMA "-41" inverters have a built-in RSS Transmitter, designed and manufactured by SMA.  This transmitter is powered from the DC side (PV) and requires 4.2V in order to start.  This means that a string of at least seven Fire Safety TS4 units is needed for the SMA RSS Transmitter to power up and operate.  This is true whether the single TS4-A-F or the dual TS4-A-2F is used, at least seven total units per string will be required.  If this will be a problem, then the Tigo external RSS Transmitter can be used instead.  In this case, the SMA internal RSS Transmitter should be disabled.  For more details, there is also an "Application Note: Tigo SMA RSS", in the Technical Documentation section of our Downloads page.

Important note for systems with 2 or more RSS Transmitters

Important: When installing a system with 2 or more RSS transmitters, it is mandatory to use the best installation practices of PLC circuits to ensure a trouble-free installation. These are documented in the PV CONDUCTOR INSTALLATION - MULTI-TRANSMITTER SYSTEMS - REQUIRED PRACTICES section of the Installation Manual - TS4-F, TS4-R-F, TS4-A-F, RSS Transmitter.

If you have design questions, feel free to email training@tigoenergy.com.

Related Content:

Installation Manual - TS4-F, TS4-R-F, TS4-A-F, RSS Transmitter