When to use: Use this designer when scoping an access-control deployment to size controllers, input/output points, reader ports, and power supplies and to produce a credential / door point schedule. Define each opening's locking hardware, reader configuration, and protocol; the tool tallies points per door, assigns panels, and sizes the PSU with a 25% margin plus battery backup. Reflects OSDP multidrop wiring savings vs. legacy point-to-point Wiegand, and flags NFPA 101 free-egress requirements for maglocks (fail-safe + REX + fire-alarm release).
| Door | Locking Hardware | Reader | Protocol | Panel · Port | Inputs | Outputs | Lock mA |
|---|---|---|---|---|---|---|---|
| Door 1 | Electric Strike Fail-secure (typ.) | Single reader IN | OSDP / SIA | P1 · #1 | 2 | 1 | 250 |
| Door 2 | Electric Strike Fail-secure (typ.) | Single reader IN | OSDP / SIA | P1 · #2 | 2 | 1 | 250 |
| Door 3 | Electric Strike Fail-secure (typ.) | Single reader IN | OSDP / SIA | P1 · #3 | 2 | 1 | 250 |
| TOTALS | 6 | 3 | 1110 | ||||
OSDP (SIA / IEC 60839-11-5): bidirectional, supervised (tamper/fault detection), encrypted with AES-128 Secure Channel, and multidrop — up to ~8 readers on one RS-485 bus, saving controller ports and wiring. Your design has 3 OSDP door(s), enabling shared-bus wiring. Wiegand: legacy, unencrypted, unsupervised, and point-to-point — one home-run cable and one dedicated reader port per reader.
This tool helps security engineers design access control deployments by sizing controllers, input/output points, reader ports, and power supplies for each door. It is used during the design phase to produce a credential/door point schedule and verify OSDP vs Wiegand wiring strategies.
Each controlled opening requires a locking device, one or two readers, supervised inputs (door position switch and request-to-exit), and at least one output relay. The controller panel aggregates these points: a 4-door panel, for example, provides four reader ports, eight supervised inputs, and four relay outputs as a typical baseline.
Power supply sizing starts from the sum of all lock holding currents (electric strikes 200–350 mA, maglocks 400–600 mA) plus reader draw (OSDP readers ~110 mA, Wiegand ~90 mA), then applies a 25% inrush margin. Battery backup is sized for 4-hour standby per UL 294 Level II.
OSDP (SIA / IEC 60839-11-5) readers multidrop on a shared RS-485 bus — up to eight readers per bus port — saving reader port capacity and wiring cost compared to legacy point-to-point Wiegand connections.
SIA OSDP / IEC 60839-11-5 governs bidirectional, supervised, AES-128 encrypted reader communication over RS-485. UL 294 sets access control system unit requirements including attack resistance, endurance, and standby power levels (Level I–IV). NFPA 101 §7.2.1 mandates free egress from all occupancies — maglocks on egress doors must be fail-safe, release on loss of power, include a request-to-exit sensor, and release on fire alarm activation. NFPA 101 §7.2.1.6 covers delayed-egress maglocks (15 s or 30 s delay with audible alarm). ICC A117.1 / ADA standards govern power-assisted doors at accessible openings.
Panel selection must account for growth — unused door capacity costs little but a future panel expansion is expensive. Choose a panel type that leaves 20–30% spare capacity. OSDP is preferred over Wiegand for new installations because it provides bi-directional supervision (tamper, fault), AES-128 encryption, and multidrop wiring efficiency; legacy Wiegand is unencrypted and susceptible to relay attacks.
Maglocks require fail-safe fail-mode, meaning they release when power is lost. Electric strikes and electrified mortise locks are typically fail-secure, retaining latch engagement on power loss — the appropriate mode depends on occupancy egress requirements. Always coordinate with the fire alarm system for automatic release on alarm.
Set the global panel type and supply-side current defaults, then add each controlled door and configure its locking hardware, reader configuration (single IN or IN+OUT), communication protocol, and supervised inputs (REX, DPS, ADA operator). The tool automatically assigns each door to a panel and port, sums all input/output points and current draw, and recommends the next standard PSU amperage with 25% margin plus a 4-hour battery backup. Review the Credential/Door Point Schedule for the design package.
OSDP (SIA / IEC 60839-11-5) is bidirectional, supervised, AES-128 encrypted, and supports multidrop RS-485 wiring — multiple readers share one bus. Wiegand is a legacy unidirectional, unencrypted, point-to-point protocol with one dedicated cable run per reader. OSDP is recommended for all new installations.
NFPA 101 requires free egress from all occupancies at all times. A maglock holds the door closed electromagnetically; if it fails locked on a fire or power outage, occupants cannot exit. Fail-safe means the lock releases when power is removed, ensuring egress is always possible.
UL 294 Level II requires 4 hours of standby power. Some occupancies and AHJs require more — NFPA 101 and local fire codes may mandate up to 24 hours for fire command centers. Always verify the AHJ requirement for the specific occupancy.
Common panels come in 2, 4, 8, and 16 door configurations. Each door port provides reader port(s), supervised input circuits, and a relay output. Panels can be networked together for large facilities. Choose the panel size so each panel operates at 70–80% capacity to allow for growth.
REX (Request-to-Exit) is a sensor — typically a passive infrared motion detector or a push button — mounted on the secure side of a door. It signals the controller to unlock or suppress the door-held-open alarm when an occupant approaches from inside. It is required on maglocks per IBC and NFPA 101 egress rules and is standard good practice on all controlled doors.
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