Siemens 6ES7321-1BH02-0AA0 SIMATIC S7-300 SM 321 Digital Input Module
01Product Overview
Siemens 6ES7321-1BH02-0AA0 is an isolated SIMATIC S7-300 SM 321 digital input module with 16 inputs for 24 V DC signals and one 20-pole front connector. The inputs comply with the documented IEC 61131 Type 1 characteristic.
02Specifications
| Manufacturer | Siemens |
|---|---|
| Article Number | 6ES7321-1BH02-0AA0 |
| Product Family | SIMATIC S7-300 SM 321 |
| Module Type | Isolated digital input module |
| Digital Inputs | 16 |
| Rated Input Voltage | 24 V DC |
| Permissible Supply Range | 20.4...28.8 V DC |
| Signal 0 Range | -30...+5 V |
| Signal 1 Range | 13...30 V |
| Input Current at Signal 1 | 7 mA typical |
| Input Delay | 1.2 ms typical |
| Input Characteristic | IEC 61131 Type 1 |
| Power Loss | 3.5 W typical |
| Front Connection | 1 x 20-pole |
| Lifecycle | Product cancelled from 1 October 2025; listed as spare part |
03Features
Design and Functions
- Sixteen isolated 24 V DC input channels fit the standard S7-300 signal-module format.
- IEC 61131 Type 1 input behavior supports common industrial switching devices.
- All 16 inputs can be used simultaneously within the documented installation-temperature limits.
- A 20-pole front connector separates field wiring from the replaceable module.
- Channel states are available to the controller program through the configured process image.
- The documented input delay is fixed rather than parameterized.
Product Identity
Manufacturer: Siemens
Model: 6ES7321-1BH02-0AA0
Product Type: SIMATIC S7-300 SM 321 Digital Input Module
04Applications
- Limit switch, relay contact, and 24 V DC sensor inputs.
- Machine and process interlocking in SIMATIC S7-300 systems.
- Legacy S7-300 maintenance using a 16-channel isolated input module.
- Control panels that retain the original 20-pole terminal mapping.
05Lifecycle & Replacement
- Siemens lists the article as a spare part and cancelled from 1 October 2025.
- Back up the hardware configuration and document all 16 signal assignments.
- Match the 20-pole connector, input common arrangement, sensor supply, and voltage levels.
- After exchange, verify every channel from the field device through the controller diagnostics.
- Any migration should include rack, connector, address, wiring, and software conversion planning.
FAQFrequently Asked Questions
What is
6ES7321-1BH02-0AA0 is a 16-channel isolated SIMATIC S7-300 SM 321 digital input module for 24 V DC signals.
Which system is it designed for?
It is designed for compatible SIMATIC S7-300 racks and uses a 20-pole front connector.
What must be matched before ordering?
Match the complete model code, installed hardware, electrical ratings, field wiring, connector arrangement, required approvals, and project revision.
What should be recorded before replacement?
Record the module address, all 16 channel assignments, input commons, sensor supplies, terminal mapping, and diagnostic state.
How should lifecycle status be handled?
Siemens lists the article as a cancelled spare part; preserve an exact spare or engineer a system migration.
What should be checked after installation?
Verify wiring, supply conditions, configuration, diagnostics, channel behavior, alarms, and the controlled process under the approved commissioning procedure.
+Recommended Models
| LNL-1200 | ARD-CPU-RM A1110014 | W440-M 203947-02 |
| 301ST | RL28-8-H-2000-IR/47/105 | DIN-AP2 |
| ABB SA/S 8.16.5S | 2CDG110167R0011 | APIN0315 |
| BM12 RS 616-661 | 8100261 | 1756-L61/B PN-13837 |
| SSR-3F/BL | PUB4024S | 700-CF220ZS |
| WL185 | DVI-M PN:26-584-01 | AP-ANT-4 3EM17860BTBV |
| T775B2040 | 6SE6400-3TC00-4AD2 | 2CDG 120 044 R0011 |
| HRI-A4 | X12091814-1ABS | TM3DI32K |
| 3DT-NCMCU1.88 | BZME1-A20-BT | AP-101-11-2 |
| DS2100N-1204 | DGBP-E2CRS | MTN649325 |
