Delta RMC151 - Manual (Page 423)

6 Communication
Discrete I/O augments the communications of the RMC. Discrete I/O is typically faster and
more deterministic than the communications, and is therefore well-suited for starting a
sequence in one or more RMCs at a specific time.
Some example uses of discrete I/O for communications:
• Start or Stop User Programs
Use the Program Triggers to start and stop User Programs based on an input.
• Affect flow of User Programs
Use inputs in the Conditional Jump link type to make link conditions that affect the
flow of the User Programs.
• General input and output
Turn outputs on and off from within User Programs and use inputs in Expressions.
For details on using these features, see the following topics:
• Using Discrete I/O
• Configuring Discrete I/O
Discrete I/O Modules
The following discrete I/O modules are available on the RMCs:
RMC70 RMC150
• D8 Expansion Module
8 discrete I/O, 12-24VDC,
individually programmable as
inputs or outputs.
• Axis Module DI/O
Each axis module contains one
discrete Fault Input and one
discrete Enable Output. These are
intended for specific purposes, not
as general-use discrete I/O.
• DI/O Module
8 discrete outputs, 5-24VDC.
18 discrete inputs, 5-24VDC.
• RMC150E CPU I/O
The RMC150E CPU includes:
2 discrete inputs, 12-24VDC.
2 discrete outputs, 12-24VDC.
6.7. Command Request and Acknowledge Bits
The Command Request and Command Acknowledge bits provide synchronization of
commands and status information between the PLC and RMC. Using these bits is optional.
These bits are available only when writing commands directly to the Command Area registers
from an external host controller, such as a PLC.
For many PLC applications, they are very important. When reading status bits and status
registers, these bits let the PLC know that the data being requested is valid. For example,
after a Move command is issued, the In Position status bit is not valid until the RMC has
informed the PLC that it received the command. The RMC does this by matching the Command
Acknowledge bit to the Command Request bit.
PROFIBUS
These bits are available only for the Basic/Enhanced modes. The PROFIBUS I/O mode
does not use the command area, and instead uses a simple method to handshake data
between the PLC and RMC.
For details on using the REQ and ACK bits with PROFIBUS Basic/Enhanced modes, see the
Basic/Enhanced PROFIBUS Modes topics.
Serial (RS-232/485) and Ethernet
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