12
Notice
When data setting is changed by front keypad operation, the data that is related to the changed
item is also changed automatically as shown in Example 1 below.
However, when the data setting is changed by communication function, the related data does not
change as shown in Example 2 below. (Only the changed data is altered.)
(Example 1) Scaling high limit: 1370
SV :
1000
When Scaling high limit is changed to 800 by the front keypad operation, both Scaling
high limit and SV are changed to 800 .
(Example 2) Scaling high limit: 1370
SV :
1000
When Scaling high limit is changed to 800 by communication function, Scaling high
limit is changed to 800 , however, SV is maintained at the same temperature 1000 .
8. Specifications
Cable length
: Maximum communication distance 1.2km
Cable resistance: Within 50 (Terminator is not necessary or
120 or greater on one side.)
Communication line : Based on EIA RS-485
Communication :
Half-duplex
Communication speed : 9600bps (2400, 4800, 9600, 19200bps) Selectable by keypad operation
Synchronous system : Start-stop synchronous
Code form
: ASCII, binary
Error correction
: Command request repeat system
Error detection
: Parity check, Checksum (LRC), CRC
Data format
Start bit : 1
Data bit : 7, 8
Parity : Even, Odd, No parity
Stop bit : 1
9. Troubleshooting
If any malfunctions occur, refer to the following items after checking the power supply to the master
and the slave.
• Problem: If it is unable to communicate
Check the following
The connection or wiring of communication is not secure.
Burnout or imperfect contact on the communication cable and the connector.
Communication speed of the slave does not coincide with that of the master.
The data bit, parity and stop bit of the master do not accord with those of the slave.
The instrument number of the slave does not coincide with that of the command.
The instrument numbers are duplicated in multiple slaves.
Make sure that the program is appropriate for the transmission timing.
•
Problem: Though it is able to communicate, the response is 'NAK'
.
Check the following
Check whether a non-existent command code has been sent or not.
The setting command data exceeds the setting range of the slave.
The controller cannot be set when such as AT is performing.
The operation mode is under the front keypad operation setting mode.
32-8, KUMANO-CHO, ITABASHI-KU, TOKYO 173-8632
Telephone
: + 81-3-3956-2171
Facsimile
: + 81-3-3956-0915
E - m a i l
W e b s i t e
: http://www.chino.co.jp/
INE-359 April-'05 GT120 (1
st
edition)
Printed in Japan
