The Siemens 6ES7321-1BH02-0AA0 is a SIMATIC S7-300 SM 321 digital input module with 16 isolated inputs for 24 V DC signals. It reads field devices such as pushbuttons, limit switches, proximity sensors, and relay contacts and reports their states to the S7-300 CPU over the backplane bus.
The module mounts on the S7-300 rail and requires a 1x 20-pin front connector (sold separately).
Technical Specifications
Series
SIMATIC S7-300, SM 321
Module type
Digital input module
Inputs
16 DI, isolated
Input voltage
24 V DC
Front connector
1x 20-pin (required, not included)
Status indication
Green LED per channel
Mounting
S7-300 mounting rail
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Extend your warranty coverage at checkout2 yrs included free
Pricing for this item — you’ll pick a term on the checkout page.
Extended plans are available at checkout on items $200 and up.
+1 yr → 3 total$65/yr$65.10 · thru 2029
+3 yrs → 5 total$58/yr$173.60 · thru 2031
+5 yrs → 7 total$43/yr$217.00 · thru 2033
BEST VALUE+8 yrs → 10 total$33/yr$260.40 · thru 2036
Full defect protection · free RMA evaluation & repair · same‑day replacement when in stock
Description
The Siemens 6ES7321-1BH02-0AA0 is a SIMATIC S7-300 SM 321 digital input module with 16 isolated inputs for 24 V DC signals. It reads field devices such as pushbuttons, limit switches, proximity sensors, and relay contacts and reports their states to the S7-300 CPU over the backplane bus.
The module mounts on the S7-300 rail and requires a 1x 20-pin front connector (sold separately).
Technical Specifications
Series
SIMATIC S7-300, SM 321
Module type
Digital input module
Inputs
16 DI, isolated
Input voltage
24 V DC
Front connector
1x 20-pin (required, not included)
Status indication
Green LED per channel
Mounting
S7-300 mounting rail
Part Number Breakdown
Part number reference — 6ES7321-1BH02-0AA0
SIMATIC S7-300, Digital input SM 321, isolated, 16 DI, 24 V DC, 1x 20-pole
Official Siemens catalog description.
Product family
SIMATIC S7-300 SM 321 Digital Input Module
Series
SIMATIC S7-300
Type
io module
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Documentation
Documentation & assistant
Open the official documents, or ask the assistant and get the page it came from.
Send in your item for a free evaluation and repair quote. Use our RMA form or email a repair request to service@iac.us.com , and we will contact you to assess your situation and offer shipping information.
Technical Support
Need help with installation, configuration, or troubleshooting? Our technical experts are available to assist you.
Industrial Automation Co. is a premier supplier of replacement and aftermarket industrial components. In addition to the 6ES7321-1BH02-0AA0, we offer hundreds of Siemens parts available now in our warehouse. Most of our automation components ship on the same day and are covered by our two-year service warranty. Contact us to order your Siemens replacement parts today.