README
This folder contains subfolders for each different type of IV Swinger
PCB.  Each subfolder contains an EAGLE subfolder with the schematic and
board files created with the free version of EAGLE.  There is also a
Gerber subfolder with the manufacturing files (in a zip archive) and a
PDF subfolder with PDFs of the schematic and images of the top and
bottom of the PCB.

All PCBs are Arduino "shields" that replace the PermaProto board in the
original IV Swinger 2 design.  They plug onto the top of the Arduino.
All are 2-layer boards.


IV_Swinger_2_module
-------------------
  This is the version for PV modules that requires an external
  electromechanical relay (EMR) module, just like the original. The only
  external wiring is between one screw-terminal block on the PCB and the
  relay module and between another screw-terminal block and the binding
  posts.  Additional external wires are required for the optional
  temperature and irradiance sensors.

  RevB
  ----
  Based on RevB of the SSR-based module version. The main purpose of
  this revision is to make the SSR and EMR versions as similar as
  possible, namely:

     - the connections to the binding posts are both on a screw-terminal
       block on the left end of the board (like SSR version)

     - pads are provided for the bypass diodes (like SSR version)

     - the current-carrying path from the shunt is now isolated in a
       stub off the ground plane (like SSR version)

     - R3 is now connected to the shunt with a dedicated trace (like SSR
       version)

     - Connections to EMR are from a second screw-terminal block that is
       located on the board where the SSRs are in the SSR version

  Note that there is nothing "wrong", per se, with the RevA board. This
  just cleans a few things up and makes it much easier to compare it
  with the SSR version.
  
  Status:   Verified
  To order: Submit Gerber files to www.pcbway.com

  RevA
  ----
  Status: OBSOLETE (but bug-free)



IV_Swinger_2_cell
-----------------
  This is similar to the IV_Swinger_2_module Arduino shield, but it is
  for use with PV cells.

  RevA
  ----
  Status:   Verified
  To order: Submit Gerber files to www.pcbway.com



IV_Swinger_2_ss_mod
-------------------
  This is similar to the IV_Swinger_2_module Arduino shield, but it uses
  three solid-state relays (SSRs) instead of the one electromechanical
  relay (EMR) module.  The only off-board connections are to the PV
  module itself (PV- and PV+). These can go to binding posts, or can be
  connected directly to wires with MC-4 connectors on their ends.

  RevB
  ----
  Status: Verified

  To order: Submit Gerber files to www.pcbway.com

  RevA
  ----
  Status: OBSOLETE (bugs: Issue #40, Issue #41; not viable)



IV_Swinger_2_ss_cell
--------------------
  This is similar to the IV_Swinger_2_ss_mod Arduino shield, but it is
  for use with PV cells.  It requires four SSRs.

  RevB
  ----
  Status:   Verified
  To order: Submit Gerber files to www.pcbway.com

  RevA
  ----
  Status:   OBSOLETE (bug: Issue #49, rework possible)


--------------------------------------------------------------------------------

Advantages of EMR designs:
  - EMR module is inexpensive (~$2), vs three/four SSRs (~$21/$28)
  - "Clicks" tell you it's working
  - EMR module is easy to replace if it goes bad
  
Advantages of SSR designs:
  - On-board:
     - No wires
     - No relay module to mount
  - Rated at 100V
  - No mechanical wearout
  - Silent

NOTE: The IV Swinger 2 Arduino code and application software work with
      all four variants.