Tools & calculators
Size the 24V supply for your panel — gateway + IO cards + sensors
Add up the current draw of a Wiman gateway plus IO expansion plus your sensor loads, with headroom for inrush and a recommended PSU size.
Gateway
Pick the Wiman gateway at the heart of the panel.
I/O expansion
How many of each card are stacked on the bus.
External load
Total mA pulled by field sensors / transmitters powered from the same rail.
Supply
Bus voltage and the safety margin above peak draw.
Supply voltage
How this is calculated
The maths behind the recommendation
Wiman gateways draw two distinct current profiles — a quiet steady-state for normal polling and a much higher peak when the cellular radio attaches or the modem renegotiates. A panel supply has to ride out the peak, not just the average.
The formulae
steady_mA = gateway_typical + sum(io_cards) + external_mA
peak_mA = gateway_peak + sum(io_cards) + external_mA
power_W = (peak_mA / 1000) × V_supply
psu_A = (peak_mA / 1000) × (1 + headroom%/100)
psu_W = psu_A × V_supplyAssumptions
- I/O cards are treated as steady — their inrush is negligible against the gateway's modem.
- External sensor / transmitter load is taken at the value you enter (peak == steady).
- Cellular gateways draw their peak briefly during PDP context setup; budgeting for the peak avoids brown-out resets.
- The default 30% headroom matches our standard project practice for a single-rail 24V DIN panel.
- PSU class is picked by the smallest standard DIN-rail brick at or above the headroomed current.
Picking the PSU class
- ≤ 2.0 A — 24V/2A DIN-rail (compact, single gateway)
- ≤ 2.5 A — 24V/2.5A DIN-rail (one gateway + a few I/O cards)
- ≤ 5.0 A — 24V/5A DIN-rail (full I/O stack + active sensors)
- ≤ 10 A — 24V/10A DIN-rail (multi-gateway panel or heavy sensors)
- > 10 A — 24V/15A DIN-rail, or split across two supplies for redundancy
Need help sizing a deployment?
Our engineers will validate the numbers against your real device list and recommend the right gateway.