Hi,
Im trying to develop a basic 4 port AO/DO test box so I can interface with my DAQ to simulate instrument signals; 4No. 1-5V 4-20mA AO, and 4 No. 5V discrete outputs
Under no power conditions, my DAQs input impedance is 140k, however on power up its goes very high impedance, but Ive used 140K worst case as my simulated loads
Ive selected 2.5K pots at 10% tolerance to ensure I mange to sweep the who 1-5 range. Originally i had 1K pots selected, but wasnt convinced id be able to get as low as 1V.
Ive used 10k pull down resistors for my DOs, and added status LEDs (dont pay attention to the model on my schem) Ive selected LED resistors based on an LED with a forward current of 20mA at 5V.
Any concerns or suggestions?
Many thanks
Im trying to develop a basic 4 port AO/DO test box so I can interface with my DAQ to simulate instrument signals; 4No. 1-5V 4-20mA AO, and 4 No. 5V discrete outputs
Under no power conditions, my DAQs input impedance is 140k, however on power up its goes very high impedance, but Ive used 140K worst case as my simulated loads
Ive selected 2.5K pots at 10% tolerance to ensure I mange to sweep the who 1-5 range. Originally i had 1K pots selected, but wasnt convinced id be able to get as low as 1V.
Ive used 10k pull down resistors for my DOs, and added status LEDs (dont pay attention to the model on my schem) Ive selected LED resistors based on an LED with a forward current of 20mA at 5V.
Any concerns or suggestions?
Many thanks
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