Troubleshooting
HEC
5-1
5
Troubleshooting
The table below shows the solutions for the problems.
Problem
Cause
Solution
Communication cannot be
made.
A wrong connecting cable is used.
Connect the host and the thermo-
con with the following cables:
A cross cable for RS-232C
A straight cable for RS-485
The settings of the host and
thermo-con are not consistent with
each others.
Make the following settings of the
host and the thermo-con
consistent:
Unit Number, Baud Rate, Parity Bit,
Data Length, Stop Bit
The program is incorrect.
Ensure that the program is made
properly according to this operation
manual. (Control code, command
code, checksum, etc.)
The communication method is
incorrect.
Use the communication method
suitable for the specification of the
thermo-con (RS-485, RS-232C).
It is influenced by the noise from
outside.
Use a shield wire for the cable, and
ground the shield to the field
ground.
It is influenced by the reflected
wave.
Install a terminating resistance.
Temperature cannot be set.
Four digits are not input for the
setting temperature.
Input four digits for the setting
temperature. As 0.1 deg.C is the
minimum indication unit, input 0
(=30H) in the hundredths place.
Value out of the setting range is
input.
Set it within the temperature setting
range (between 10.0 and 60.0
deg.C).
Communication cannot be
continued.
It exceeds the writable capacity of
EEPROM (approx. 1 million times).
Ask SMC for repair.
The connecting cable comes off or
broken.
Check the connecting cable.
The thermo-con does not give
a correct answer.
The host sends more than one
communication data successively.
When sending communication
data, wait until an answer from the
thermo-con is received to send the
next data.