Omron CQM1H-SCB41 Operation Manual page 110

Using Protocol Macros
Note 1. Observe the following precautions when using the Restart Flag.
• The Restart Flag is used to initialize the communications ports. When it is
turned ON, either with a ladder program or with the monitor function of the
Support Tool, restart processing will begin after the protocol macro is exe-
cuted. Once restart processing is completed, the Restart Flag will turn
OFF again. The protocol macro will not end if this flag is ON during its
execution. To restart regardless of its executable/non-executable status,
turn ON the Forced Abort Bit (20711/20715) also.
• To execute PMCR( ) following the restart processing, wait longer than
the CPU Unit cycle time + 15 ms. This will allow the restart processing
inside the communications board to be completed. If PMCR( ) is exe-
cuted during the restart processing, a system error (FAL 9C) will occur,
and the protocol macro may not be properly executed.
2. If communications errors or retries occur with an RS-485 2-wire connec-
tion, use the following countermeasure.
This is possible with products of Lot No. 0320 or later.*
*Reading lot numbers
0 3 2 0
...Produced February 3, 2000
Production year:Last digit of the year
Production month: 1 to 9, X (10), Y (11), Z (12)
Production day: 01 to 31
When the serial communications mode for the port of the Serial Commu-
nications Board is set to Protocol Macro mode, and the send control pa-
rameter in the protocol macro is set to modem control, the following special
auxiliary bit flags are enabled.
Bit address
20706 Port 1 Echoback Disable
Mode Flag
1: Echoback disabled, 0:
Echoback enabled
20707 Port 2 Echoback Disable
Mode Flag
1: Echoback disabled, 0:
Echoback enabled
20406 Port 1 Echoback Disable
Mode Monitor Flag
1: Echoback disabled, 0:
Echoback enabled
20407 Port 2 Echoback Disable
Mode Monitor Flag
1: Echoback disabled, 0:
Echoback enabled
With the
Echoback Disable Mode Flag (Port 1: 20706, Port 2: 20707) set to 1 (ON)
and the RS-485 2-wire connection used, the data sent from the port of the Serial
Communications Board will be blocked by software from returning to the reception
line of the same port as long as the RS signal is set to 1 (ON).
If communications errors or retries occur with the 2-wire connection, use a
ladder program to form a circuit that sets the
1 (ON).
Also, the data that is received during data transfer (while the RS signal is ON) with
the Echoback Disable Mode is not input to the system, nor is it reflected in the CX-
Protocol trace data. Changes in the Echoback Disable Mode Flag (Port 1: 20706,
Port 2: 20707) from 0 (OFF) to 1 (ON) are always input to the system while the lad-
der program is running, but the 0 (OFF) state is only input to the Serial Communi-
cations Board at the start of the ladder program. Therefore, to cancel the Echoback
Function
Sets the Serial Communica-
tions Board.
Sets the Serial Communica-
tions Board.
Used to monitor the setting of
the Serial Communications
Board.
Used to monitor the setting of
the Serial Communications
Board.
Echoback Disable Mode Flag to
Section 5-7
Description
95