4-1
4. Connections
4-1
Cautions on connections
4-2 Terminal boards (rear panel)
The terminal boards are roughly divided into
①
measuring input terminals,
②
power terminals,
③
communication
I/F terminals, contact output terminals, external drive terminals, and
④
alarm output terminals. Terminals
③
and
④
are not always mounted depending upon the unit because of their option specifications.
The above figure includes option terminals.
1. Feed source power supply
●
For feeding power to the unit, use a single-phase power
source having the stable voltage without any distorted
waveform for the purpose of preventing wrong operation.
2. Separate the power supply from strong electric circuits
●
Avoid connecting the input /output lines in the vicinity of
and/or in parallel with a drive power line or other strong
electric circuits. Separate the unit from them more than
50cm if the unit is in the vicinity of and/or in parallel with
them.
3. Separate the thermocouple input from a heat source
●
Separate the terminals from a heat source (a heating
body) for reducing a reference junction compensation
error. Avoid the solar radiation or the like.
4. Separate the unit from a noise source
●
Separate the unit from a noise source as far as possible,
otherwise an unexpected trouble may occur. Take a
noise-preventive measure, if the unit cannot be
separated form a noise source.
Major generation
sources
●
An electromagnetic switch or the like
●
A power line having waveform distortion
●
An inverter
●
A thyristor regulator
Countermeasure
Insert a noise filter between the power
supply and input/output terminals.
A CR filter is used in many cases.
5. Use crimp style terminals
①
Attach crimp style terminals to the connection cord ends for
preventing terminals from being loosened or disconnected
or a short circuit failure across terminals.
②
Use crimp style terminals each having an insulation sleeve
for preventing an electric shock accident.
6. Unused terminals
●
Don’t use any unused terminal as a relaying terminal,
otherwise electric circuits may be damaged. For unused
terminals, short plus and minus terminals for preventing
the influences of external noises.
②
Power terminal board
③
Communication I/F terminal, contact output terminal,
and external drive
①
Measuring input terminal board
④
Alarm output terminal board
