3. Connecting to an External Device
ADI16-4(FIT)GY
13
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The analog signal input to the [+] and [-] inputs must not exceed the maximum input voltage with
reference to the analog ground of the module. Exceeding the input voltage can damage the
module.
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Converted data is undefined when either of the [+] and [-] input terminals is left unconnected.
Connect both of the [+] and [-] input terminals of the channel not connected to the signal source to
the analog ground.
Current source connection examples
This section gives examples of connecting analog input signals from an external device to the Module
using a flat cable and a shielded cable.
The following example uses a flat cable to connect the Module to an external device.
Connect the [+] and [-] analog input channels of the Module to the positive and negative outputs of the
current source, respectively. Also connect the analog ground of the Module to the ground of the signal
source.
Note also that, when there are more than one current source, no potential difference must exist
between their respective GND points.
The ADI16-4(FIT)GY is isolated between its internal CPU and the external device but not between the
analog input channels and thus uses a common analog ground.
If an affecting potential difference exists between the channels, insert an isolator such as an isolating
transducer between the channels.
*1 When using a ceramic capacitor, make the lead as short as possible.
Figure 3.5. Current input connection
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Converted data is undefined with no analog ground connected.
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If the connection cable is affected by noise, the analog input can be inaccurate. Route the
connection cable apart from noise sources.
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If the connecting cable is affected by noise, accurate analog input may not be made. To secure the
accuracy, place the connecting cable far from the source of the noise and put a laminated ceramic
capacitor on the connector of the module.
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The analog signal input to the [+] and [-] inputs must not exceed the maximum input voltage with
reference to the analog ground of the module. Exceeding the input voltage can damage the
module.
CAUTION
