4-5SectionApplication Procedure

53

A response will not be received with some errors, regardless of the command.
These errors are listed in the following table.
Error PC operation
Parity, overrun, or framing error during
command reception. (Same even for
commands address to other Units.)
The Communications Error Flag will be turned ON, an error code will
be registered, and receptions will be reset. (The error will be cleared
automatically if communications restart normally.)
The Communications Error Flags are as follows:
Peripheral port: AR 0812
Built-in RS-232C port: AR 0804
Serial Communications Board port 1: IR 20104,
Serial Communications Board port 2: IR 20112
A command is received that does not have the
@ character at the beginning of the first frame. The command will be discarded.
Incorrect node number (Not a local unit or over
31) The command will be discarded.
The data in an intermediate or final frame for
multiframe writes is 2 bytes or longer. An FCS error will occur.
4-5 Changes from Previous Products
There are differences between Host Link Systems created using the CQM1H-
series Serial Communications Boards in comparison to Host Link Systems
created with Host Link Units and CPU Units in other PC product series. These
differences are described in this section.

4-5-1 RS-232C Ports

Take the following differences into consideration when changing from an exist-
ing Host Link System to one using an RS-232C port on a CQM1H-series CPU
Unit or Serial Communications Boards.
Previous Model number Changes required for CQM1H-series product
products Wiring Other
C-series Host
Link Units 3G2A5-LK201-E
C500-LK203
3G2A6-LK201-E
The connector has been
changed from a 25-pin to a
9-pin connector.
The CQM1H-series
products do not support the
ST1, ST2, and RT signals
and wiring them is not
required.
The following changes are necessary for
systems that sync with ST1, ST2, and RT.
Synchronized transfers will no longer be
possible.
Half-duplex transmissions will be possible
with the CQM1H-series product, but the host
computer’s communications program,
hardware, or both will need to be altered.
The following changes are necessary for
systems that did not sync with ST1, ST2,
and RT.
It may be possible to use the host computer
programs without alteration as long as the
same communications settings (e.g., baud
rate) are used. It may be necessary, however,
to change programs to allow for different text
lengths in frames or different CQM1H
command specifications. (See note.)
C200H-LK201 The connector has been
changed from a 25-pin to a
9-pin connector.
It may be possible to use the host computer
programs without alteration as long as the
same communications settings (e.g., baud
rate) are used. It may be necessary, however,
to change programs to allow for different text
lengths in frames or different CQM1H
command specifications. (See note.)