Siemens 6ES7321-1BH02-0AA0 (SIMATIC S7-300): SIMATIC S7-300, digital input SM 321, isolated, 16 DI, 24 V DC, 1x 20-pole.
The SIMATIC S7-300 is the Siemens modular PLC that still runs a very large number of machines and process lines. CPUs, signal modules and power supplies mount side by side on the S7-300 profile rail and connect through U-shaped bus connectors on the back.
See our Siemens range.
Siemens lists this order number as a spare part, which means it is still supplied for existing installations while newer versions exist for new projects. We supply the exact order number for like-for-like replacement and can quote the current version too.
Technical data
| Siemens order number | 6ES7321-1BH02-0AA0 |
|---|---|
| Digital inputs | 16 |
| Input delay | No |
| Power loss, typ. | 3.5 W |
| Permissible supply range | 20.4 V … 28.8 V |
| Dimensions (W x H x D) | 40 x 125 x 120 mm |
| Weight, approx. | 0.2 kg |
| Condition | New, original Siemens |
Key features (per Siemens)
- SIMATIC S7-300
- Digital input SM 321
- Isolated
- 16 DI
- 24 V DC
- 1x 20-pole
Typical applications
- Spare-part stock for maintenance teams
- Keeping an installed S7-300 system running before migration
- Machine and process-line controllers
- Replacing a failed CPU, I/O or power supply module
Compatibility and replacement
Use exactly the same order number when possible, because the hardware configuration in STEP 7 or TIA Portal refers to it. Check the firmware version of a CPU on the label of the old unit; if a newer version is supplied, it can normally replace the older one, but confirm with your hardware configuration.
What to check first
- Look for signs of overvoltage, water or heat damage in the cabinet so the new part does not fail for the same reason.
- Note the firmware version printed on the old unit; TIA Portal or LOGO! Soft Comfort must support it.
- Back up the program and parameters from the old device if it still runs.
Frequently asked questions
Which software is used?
STEP 7 (SIMATIC Manager) or TIA Portal, depending on the version used for the existing project.
Does it need a front connector?
Signal modules use a separate 20-pin or 40-pin front connector (6ES7392-…), which is ordered separately unless it is the item itself.
Can you help me identify the right replacement?
Yes. Send us a photo of the label of the old part, or its full order number, and we will confirm the exact match or the official successor before quoting.
Can I get a datasheet?
The official manufacturer datasheet is the source of the technical data above; we can send the PDF with the quotation on request.
Can I get a price and delivery time?
Prices are quoted on request. Send the order number, quantity and delivery country on WhatsApp and we will reply with price and delivery time; air shipping is usually 5 to 7 days once ready, with a 1-year warranty.
How to order
Message us the order number and quantity. For breakdowns, tell us the delivery address and we will offer the fastest shipping option. If the exact part is discontinued, we confirm the official successor before quoting.
Need it fast? Send the order number, quantity and delivery country on WhatsApp or through the inquiry form and we reply with a quotation the same working day. All parts are new and original, covered by a 1-year warranty, and ship worldwide by air in 5 to 7 days once ready (shipping, payment and warranty). Local agents: Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
