Crestron cen-io User Manual

Ethernet Input/Output Module 

Crestron CEN-IO

When a logic high signal is placed on <o1> through <o8>, the output pin is shorted 
to ground (switch S1-B in the reference diagram is closed).  When a logic low signal 
is placed on <o1> through <o8>, the output pin is driven to +5V (switch S1-B in the 
reference diagram is open).  This default behavior may be modified by placing a 
logic high signal on <pullup1-dis> through <pullup8-dis>.  When the pullup resistor 
is disabled (switch S1-A in the reference diagram is open) and the corresponding 
<o> signal is driven low, the output pin floats.  When the pullup resistor is enabled 
and the corresponding <o> signal is driven high, the output pin is shorted to ground. 

Each signal <o1> through <o8> has a corresponding feedback <o1-f> through <o8-
f> that is driven by the CEN-IO.  Feedback is provided from the CEN-IO for these 
values since another non-Cresnet device on the network may talk directly to the 
CEN-IO and modify its values. 

Example:  <pullup1-dis> is driven high.  When <o1> is logic low, versiport 1 is 
floating.  When <o1> is driven high, versiport 1 is shorted to ground.   

Example:  <pullup1-dis> is driven low.  When <o1> is logic low, verisport 1 is at 
+5V.  When <o1> is driven high, versiport 1 is shorted to ground. 

The CEN-IO can detect when one of its versiports is shorted to ground or driven by 
a 0 to 5 volt digital signal.  When a pin is shorted to ground, the corresponding <i1> 
through <i8> signal is driven to logic high in the program.  The threshold for 
detection is < +2.5V drives the signal in the program high.  Note that for a contact 
closure input, the pullup resistor should be enabled for that particular input (this is 
the default behavior), else the input is floating. 

Example:  If versiport pin 5 is shorted to ground, <i5> is driven to a logic high level.  
When pin 5 is not tied to ground, <i5> is driven to a logic high level (as long as the 
pullup is left enabled, which is the default behavior). 

A resistive sensor (for example, a sensor that measures humidity) or a voltage source 
may be tied to a vesiport.  This sensor or source is represented by box "A" in the 
reference diagram. 

When a resistive load is tied to a versiport, the corresponding pullup resistor must be 
enabled (default behavior).  This creates a voltage divider and provides a varying 
voltage level (based on the current resistance of the sensor) for the CEN-IO to read.  
For example, if a resistive humidity sensor is tied to versiport 1, then <pullup1-dis> 
should be driven low.  The corresponding level is read as an analog value on <ain1> 
and ranges from 0 to 65535. 

When a voltage source is tied to a versiport, the corresponding pullup resistor should 
be disabled.  This allows the A/D convertor in the CEN-IO to directly read the 
voltage source's value.  For example, if a voltage source is tied to vesiport 1 then 
<pullup1-dis> should be driven high.  The corresponding level is read as an analog 
value on <ain1> and ranges from 0 to 65535 (0 to +10V on the input pin). 

The CEN-IO reports any change back to the program when an analog value changes.  
Depending on the input source, this can result in excessive traffic over the network.  
A minimum change value may be specified on a per-input basis.  This tells the CEN-
IO to wait until the corresponding analog input changes by the minimum value 
before reporting into the program.  This is useful if an input source is not clean and 
has jitter. 

•  Ethernet Input/Output Module: CEN-IO