Knowledge Base

The above picture shows the SPice10211 analog output connections. Each output can generate a 0-10V signal, with a maximum load current of 5mA, corresponding to a 2KOhm load. The outputs have internal current limiting (which is not the same as being short circuit proof!).

Note: Which actual analog inputs and outputs the board maps to depends on which model of SPLat controller it is attached to. The mapping is detailed under Programming.

NOTE: Analog output 2 is shared with the thermistor drive circuit. If you are using a thermistor you cannot independently use analog output 2. In the case of the SL99 and MMi99/200 this also applies if you are using thermistors on the main board.

The analog output voltage is a positive voltage measured with respect to the 0V terminal. It is programmed using the analog output instructions. With X=0 this will result in 0V out, with X=255 it will result in 10V out.

The output resolution is 10 bits (1024 steps between 0 and full scale). The output is generated as a filtered pulse width modulated (PWM) signal. The filter consists of a simple 100mS RC low pass filter. For a full scale step output change, say from 0V to 10V, this will take 230mS to settle to within 10% of the full change, 450mS to settle to 1% and 550mS to settle to 0.4% (= 1 bit, i.e. the resolution of the system).

How to blow up the analog outputs

Here are some ways of blowing up the analog outputs:

  1. Connect the output to any positive voltage over 10V and program a 0V output.
  2. Short the output to 0V for extended periods of time (it may survive)

Connect the output to a negative voltage, even momentarily.