Communication Port 1 Byte/Bit Protocol Orientation Selector; Start Bit Polarity Selector - DAQ IoG User Manual

Callisto IoG
D A Q E L E C T R O N I C S
In the case where the IoG is the only node in the system (no other nodes connected via
Arcnet communication), then the node address must be set to a value of 1.
If there are several nodes connected together via Arcnet in the system (IoG or other
Callisto series), then the IoG may be set for any convenient address, provided that the
selected address is not shared by any other node in the system. If two or more nodes share
the same address, Arcnet communication problems will result.

3.6.2 Communication Port 1 Byte/Bit Protocol Orientation Selector

The seventh switch position on the DIP switch (with respect to the "SW2" PCB marking)
allows selection, on Communication Port 1, of a bit or byte oriented protocol.
Although byte-oriented SCADA communication protocols (SES-92, DNP3, IEC
60870-5-101, etc.) are more widely used, the so-called "bit-bang" protocols (CDC, PMS-
91, Conitel, etc.) are still occasionally used. As such, the byte/bit selector switch permits
either type of protocol to be selected on Communication Port 1 only.
Set this switch to the "OFF" position for Byte-oriented protocols, or "ON" for Bit-
oriented protocols.

3.6.3 Start Bit Polarity Selector

This switch applies only when the Communication Port 1 Byte/Bit selector switch in set
for bit-oriented protocol ("ON" position).
When this switch is set to the "OFF" position, Port 1 is configured to detect low-going
start bits. Most bit-oriented protocols utilize a low-going start bit, therefore this would be
the appropriate switch position for Port 1 communication using CDC, PMS-91, Conitel,
and other "bit-bang" protocols.
Setting this switch to the "ON" position configures Port 1 to detect high-going start bits.
IRIG-B time code systems, as an example, utilize a high-going start bit.
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