Overview#
The Deep Sea Electronics DSE 7320 MkII is the workhorse Auto Mains Failure (AMF) controller for single-genset standby applications across North America and most of the rest of the world. It sits at the higher end of DSE's single-set lineup, just below the paralleling-capable DSE 8610 MkII. For any single genset that needs to monitor utility power and automatically start, transfer, and stop, the 7320 is the default specification — to the point where many gen-set OEMs offer it as an upgrade option from their proprietary controllers.
The MkII designation matters: the original DSE 7320 (non-MkII) lacks Ethernet and Modbus TCP. If you're specifying a new install or replacing a non-functional unit, get the MkII.
What it does well#
Three things make the 7320 MkII the default choice for AMF applications:
- Open architecture. Modbus over both serial and Ethernet, fully published register map, free configuration software. BMS integrators don't need to call DSE for protocol assistance — everything is documented.
- Engine ECU compatibility. J1939 CAN integration with every major engine OEM out of the box. No need for intermediate gateway boards.
- Configurable I/O. Eight digital inputs, six configurable analogue/digital inputs, six configurable DC outputs, and two volt-free relay outputs — all programmable. Lets the controller handle site-specific logic (e.g., generator-room exhaust fan starts at 90% of rated load, retransfer inhibit during peak rate hours, etc.) without external PLCs.
Typical wiring topology#
A standard DSE 7320 MkII install integrates four wire groups:
- Engine harness: J1939 CAN to engine ECU + start/stop relay + traditional analog backups (oil pressure, coolant temp) for safety redundancy
- AC sensing: three-phase voltage and current CTs for both genset side and mains side (the "M" side of mains-failure)
- ATS control: dry contacts to the transfer switch's controller (Kohler MPAC, ASCO Group G, Russelectric MicroBOSS, etc.) — the 7320 commands transfer; the ATS executes
- Communications: Ethernet to BMS / monitoring system, optionally RS485 daisy-chain for legacy systems
What we see in the field#
After eight or so years of deploying 7320s across the central California coast, two patterns:
The 90% case is boring (which is good). The 7320 just runs. We've seen units with five-figure runtime hours that have never required a controller-related service call. The hardware is solid.
The 10% case is configuration drift. When facility staff or a previous service contractor modifies the controller config and doesn't document the change, troubleshooting becomes painful. The fix is upstream: insist on a baseline .dse config file backup at commissioning, and require change documentation as part of every service event. Configuration Suite makes the file management trivial — sites that don't do this are sites where someone didn't enforce the discipline.
Common upgrades and adjacent specs#
- Adding paralleling capability: the 7320 cannot parallel. If the application grows beyond N=1, the migration path is the DSE 8610 MkII or DSE 8660 (paralleling controllers in the same UI family).
- Cellular remote monitoring: add the DSE WebNet Gateway or pair with a third-party cellular Modbus gateway. The 7320's onboard Ethernet doesn't include cellular.
- Touchscreen UI: the 7320 is LCD only. For touchscreen, look at the 7450 MkII or a separate HMI.
When to spec something else#
- Paralleling required: DSE 8610 MkII or DSE 8660
- Manual/semi-auto only (no AMF): DSE 7310 MkII (cheaper, lacks mains sensing)
- Tiny budget, basic single-set: DSE 6020 / 6120 (lower I/O count, simpler UI, no Ethernet)
- Legacy panel retrofit with 4-20mA only: the 7320 doesn't have direct 4-20mA inputs; use signal converters or step up to DSE 7450 MkII
OnPoint service notes#
We stock baseline config templates for the 7320 MkII by application type (commercial standby, light-industrial, multi-tenant). Initial commissioning typically takes 2-4 hours including J1939 verification, ATS sequencing tests, BMS handshake, and three test outages. Annual service includes config backup, firmware check, and a no-load + load-bank exercise.
