Smart 200 PLC with 4 Encoders of A phase

Dear sir

I have Smart 200 PLC with 4 Encoders of A phase (Single channel). I have issue that if I connect the one Encoder to I0.0 and other is to I0.1, If I start the first motor (encoder connect with I0.0) then I am getting pulses to Both I0.0 and I0.1. If I connect only one Encoder to I0.0 then its working OK.

Same thing happen with I0.2 & I0.3. Please give me solution.

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Split from HSC in s7-200 smart.