# Converting pnp open drain transistor output to open collector for pule train

1. ## Converting pnp open drain transistor output to open collector for pule train

hi there
I have s7 1200 plc with pnp open drain transistor output to control Mitsubishi servo drive
the drive sink input so how can I convert the signal

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2. ## Re: Converting pnp open drain transistor output to open collector for pule train

Hi,

I assume the PLC output is either
* HIGH (what voltage?)
* Z (high impedance)

For low switching frequency you may simply connect a relay.

For higher switching frequency I recommend to use a transistor.
Now it depends on output logic what circuit to use.
Tell us:
PLC_High --> what output signal?
PLC_Z --> what output signal?

Tell us the input signal ranges of the Mitsubishi device:
* for HIGH (voltage and current ranges)
* for LOW (voltage and current ranges)

Klaus

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3. ## Re: Converting pnp open drain transistor output to open collector for pule train

hi,
Tell us the input signal ranges of the Mitsubishi device:
* for HIGH (voltage and current ranges)
* for LOW (voltage and current ranges)
the signal from plc 24v open drain transistor output 24v Dc

one for the pulse and another output for the direction
the input on the drive open collector (pp for the pulse input)
(np for direction)
vdd to 24 VDC
sg to the ground
plc siemens s71200
servo drive mr j2s -A
http://www.aiautomation.com.au/wp-co.../05/113788.pdf

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4. ## Re: Converting pnp open drain transistor output to open collector for pule train

Hi,

either one of us or you needs to read the datasheets ... I think it makes sense that you read it
It shouldn´t be that difficult to find out input voltages and input currents.

Sadly you don´t give the information if a PLC_HIGH should generate a Mitsubishi_HIGH or ..-LOW.

Thus I tell the simple - inverting solution: HIGH --> LOW

PLC_out -- 10k -- BJT1_base
BJT1_base -- 1k -- GND
BJT1_emitter -- GND
BJT1_collector -- Mitsubishi_in

In case the the Mitsubishi_input has no internal pullup --> you need an external pullup resistor:
24V -- R_PU -- Mitsubishi_in

BJT1 is a standard NPN transistor. In detail it depends on the (missing) voltage and currents. Try BC547
R_PU value depends on Mitsubishi input voltages and currents. Try 10k, maybe you need a lower value.

Klaus

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