Sales and repairs of SIEMENS SIMATIC S7-400 digital inputs
S7-400 digital inputs – new and refurbished parts and repairs
SIMATIC S7-400 digital inputs read the states of switches, pushbuttons and other binary signals. We supply input modules with different channel counts and functions, depending on the type.
We will send a non-binding quote within 1 hour.
- Worldwide delivery
- Our own and partner parts stock
- Professional repairs
- Parts with warranty
More about selecting S7-400 digital inputs parts
SM 421 Digital Inputs
SM 421 digital input modules connect binary signals from sensors, pushbuttons, and limit switches. Variants are available with different numbers of inputs, voltage levels, input delays, and diagnostic features.
When selecting a digital input, compare the signal voltages, the number of inputs, and the required input delay. Galvanic isolation and diagnostics are also important. These factors determine whether the module will correctly interpret the signals from your sensors and switches.
New, refurbished, and end-of-line parts from warehouses
For current SIMATIC S7-400 parts, we first verify the availability of new, genuine SIEMENS parts. We have access to an extensive network of industrial parts warehouses in Europe and around the world, which allows us to also check for refurbished, discontinued, and hard-to-find variants.
Diagnostics, Repairs, and Testing of S7-400 Parts
You can send the defective part to FOXON for diagnosis. We perform repairs on CPUs, I/O modules, communication modules, functional modules, and power supplies at specialized repair centers; after repair, the parts are functionally tested under load. If repair is not feasible, we will check for an identical new or refurbished part or a compatible replacement.
Frequently Asked Questions
Please provide the complete order number or details regarding the voltage, number of inputs, and station configuration.
Delivery times depend on the specific part and warehouse. Thanks to our access to numerous warehouses, we can typically arrange delivery within a few days; for urgent needs, we can offer express delivery within a matter of hours. For urgent requests, call us immediately—we can arrange express delivery of selected parts day or night.
Yes. Ideally, please provide the full number from the label and the quantity you need; a photo of the label will also be helpful for replacements or repairs.
6ES7421-7BH00-0AB0
6ES7421-1FH00-0AA0
6ES7421-1BL00-0AA0
from 12,10 EUR Incl. VAT
6ES7421-1BL01-0AA0
from 12,10 EUR Incl. VAT
6ES7421-7DH00-0AB0
6ES7421-7BH01-0AB0
6ES7421-1FH20-0AA0
6ES7421-1EL00-0AA0
6ES7421-5EH00-0AA0
How to capture sporadic faults on Siemens S7 PLCs
Sporadic faults on Siemens SIMATIC S7 PLCs are difficult to find using standard online diagnostics. In this article, we show how auto.spy analyzer helps capture signals, events and video on a single timeline and trace the root cause of the problem afterwards.
Question or Inquiry
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