Honeywell HC900 Safety Manual page 46

Design and Implementation of HC900 Control System - Allowable Function Blocks for Process and Safety Functions
A communication function block that expands the
write capability of the Modbus Slave function block to
8 additional data points. Multiple blocks may be
connected to the same Modbus Slave block. The
Modbus write block has 8 inputs and no outputs. The
Modbus destination for each of the eight inputs can
be configured. An enable pin lets the data value be
Modbus Write
written once per scan. The configuration data for
each point will consist of the address of the
destination device on the Modbus link, the register
address of the desired data, and the register type:
Integer or Float. Modbus writes to a function block
inside a safety worksheet are only permitted while
operating in the "RUN/Program" or "Program" modes.
A communication function block that allows the
controller to act as a master device and communicate
with slave devices via the Ethernet port of the
controller. Requires one block per slave device, up to
32 devices maximum. Only one block may be
assigned to each slave device. It supports 4 read and
4 write parameters plus provides digital indication of
communication integrity. This block does not support
Modbus TCP
bit packing and single bit writing. If the register is an
Slave
integer data type, the floating point input will be
rounded up prior to writing to the address register.
Integer values are converted to floating point values
prior to output. If a Modbus slave device does not
respond to a request, the last output value will be
maintained. Modbus writes to a function block inside
a safety worksheet are only permitted while operating
in the "RUN/Program" or "Program" modes.
A communication function block that expands the
read capability of the Modbus/TCP Slave function
block to 16 additional data points. Multiple blocks may
be connected to the same Modbus/TCP Slave block.
The Modbus/TCP read block has no inputs and 16
outputs. Up to 16 registers can be configured as the
Modbus TCP
source of data for the outputs. The configuration data
Read
for each point will consist of: the address of the
source device on the Modbus link, the register
address of the desired data, and the register type:
Integer, Float, or Bit Packed. The sixteen outputs can
be connected or tagged in the same manner as any
other function block output.
A communication function block that expands the
write capability of the Modbus/TCP Slave function
block to 8 additional input data points. Multiple blocks
may be connected to the same Modbus/TCP Slave
block. The Modbus/TCP write block has 8 inputs and
Modbus TCP
no outputs. Up to 8 registers can be configured as the
Write
data destination of the inputs. The configuration data
for each point will consist of: the address of the
source device on the Modbus link, the register
address of the desired data, and the register type:
Integer, Float.
38 HC900 Process & Safety Controller Safety Manual
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Revision 1.9
01/14