HRX-OM-M090 
Chapter 3   Transport and Setting Up 
 
3.3 Installation  HRS Series 
 
 
3-14  
3.3.6  RS-485 Communication wiring 
Serial communication RS-485, operation start/stop, setting and reading of 
circulating fluid temperature, and reading of alarm condition can be done by 
remote control. 
Refer to the Communications Operation Manual for more details.   
 
  Wiring of interface communication cable 
 
 
 
 
 
 
 
z  Connecting to PC 
RS-485 cannot be directly connected to a normal PC. Use a RS-232C/RS485 converter which is 
available on the market. 
 
 
Be sure to follow the wiring procedure below for connecting multiple thermo-chillers. 
z 
Configuration of connection 
One host computer : One thermo-chiller, or one host computer : N thermo-chillers. 
(Max. 31 thermo-chillers can be connected.) 
1
SD+
5
SG
9
SD-
SD+
SD- SG
Terminal
resistance
Master This product
(first slave)
1
SD+
5
SG
9
SD-
This product
(second slave)
1
SD+
5
SG
9
SD-
This product
(31
st
 slaves)
Terminal
resistance120Ω
 
 
Fig. 3-9 Connection of RS-485 
 
【Tips】
 
 
Both ends of the communication connection (the end nodes) need to be 
connected to the host computer. 
The terminal resistance of this product can be set by the operation display 
panel. Refer to “5.18 Communication function”. 
Be sure to shut off the breaker of the facility power supply (the user’s 
machine power supply) before wiring.