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Combination analog inputs and analog outputs


Certain ACE PLCs have a single connector with both analog inputs and outputs. The connections are as shown on the diagram at the right.

  • The first few signals on the port are analog inputs. They are 12 bit analogs, described in the analog input description. Typically, there are either 3 or 4 analog inputs in a combination port.
  • The last signals on a combination port are analog outputs. For the Ace 7096 these are 16 bit resolution outputs, which can be individually configured, using vBuilder for either 0-5V or 0-10V operation, as shown below.

There is no need to connect anything to pin 8 (VA). It is like pin 8 on the digital input and output ports – connected to 5V via a 10 ohm resistor and a diode.
Note: An amplifier after the D/A chip that we use in the 7092 is acting as a low pass filter.

If connecting to an analogue output causes the CPU to reset, this suggests that the external connection is drawing a lot of current. Adding an in-line resistor will limit the current, but if the device to which it is connected is drawing a lot of current, the voltage after the resistor will probably be reduced. Try measuring the voltage at the input and output of the resistor.