Communications Errors - Omron E5ZE Operation Manual

Communications Errors

Program
System begins communications without any
interval after the E5ZE Units are turned ON.
Unstable signal of the E5ZE, which is generated
when the E5ZE is turned ON or OFF, is read as
data by the host device.
Host device sends commands to the E5ZE
before receiving any response from the E5ZE.
Interval between the time the host device
receives a response and sends a command is
too short.
Program of the host device is incorrect.
Settings
Unit numbers set with the selectors are different
from those set using the commands of the host
device.
Pin 8 of the FUNCTION switch on the E5ZE is
ON.
E5ZE is in hardware test mode.
Termination resistance settings for RS-422 or
RS-485 communications are incorrect.
RS-422 or RS-485 settings are incorrect.
50
Probable cause Remedy
Write a program so that the system starts
communications with an interval of 5 s min. after
the E5ZE Units are turned ON.
Initialize the reception buffer of the host device
at the following stages.
• Before the host device transmits the first
command.
• After the E5ZE is turned OFF.
Write a program enabling the host device to read
the response after the host device sends any
command.
The interval between the time the host device
receives a response and sends a command
must be 20 ms minimum.
• Correct the program.
• Check the command with the line monitoring
function.
• Run a sample program with the host device.
The unit numbers must coincide.
Turn OFF pin 8 of the FUNCTION switch on the
E5ZE.
The E5ZE must be in control mode.
The E5ZE or host device located on both ends of
the E5ZE system must have termination
resistances.
Correct the communications switch settings.
Section 4-2