Here's a proposal: A circuit like this should work without significantly affecting measurement accuracy. It's important to have a low impedance ground for the clamp diodes (short connection to main system ground).
The resistors prevent unwanted failure of the clamp diodes. The clamp diodes are for protecting the EMS, not absorbing battery dump energy.
Vern
The resistors prevent unwanted failure of the clamp diodes. The clamp diodes are for protecting the EMS, not absorbing battery dump energy.
Vern