Which statement about current types on PLC input modules is true?

Which statement about current types on PLC input modules is true?

• A. Some PLC models offer input modules that mix AC and DC inputs on the same module
• B. All input modules are AC only
• C. AC and DC cannot be mixed on any module
• D. Input terminals cannot accept more than one type of current

Answer: (A)

Current types on PLC input modules can vary by design; some module families include inputs that accept both AC and DC signals on the same physical unit. This lets you wire a mix of field devices—some using AC signals and others using DC—without needing separate input modules for each type. Each input channel still operates at its rated type, and you must wire and configure channels according to whether they’re configured for AC or DC. That’s why a statement about mixed AC and DC inputs on a single module is true: it reflects real designs aimed at saving space and simplifying wiring. The other ideas aren’t accurate: many modules are not limited to AC only, DC input modules do exist, and you can’t have a single terminal handle both AC and DC at once. Plus, a module can have multiple channels that are of different types, so a terminal isn’t restricted to a single current type across the entire module.

Current types on PLC input modules can vary by design; some module families include inputs that accept both AC and DC signals on the same physical unit. This lets you wire a mix of field devices—some using AC signals and others using DC—without needing separate input modules for each type. Each input channel still operates at its rated type, and you must wire and configure channels according to whether they’re configured for AC or DC.

That’s why a statement about mixed AC and DC inputs on a single module is true: it reflects real designs aimed at saving space and simplifying wiring. The other ideas aren’t accurate: many modules are not limited to AC only, DC input modules do exist, and you can’t have a single terminal handle both AC and DC at once. Plus, a module can have multiple channels that are of different types, so a terminal isn’t restricted to a single current type across the entire module.