14
3-3. Control input and output
terminals
3-3-1. Control input terminals
Terminal
number
Signal
Explanation
11
D/Z
Sets the indicator value digitally to 0.
o
Maintain the ON state for more
than 30 msec.
This is active when Enable Digital
Zero is set to ON.
12
Hold
Holds function using hold start sig-
nals when this is ON.
This becomes disabled if the Hold
Mode is set to “OFF”.
13
Clear
This turns on when a hold is cleared
in any hold mode except sample
hold.
Whether Clear signals are enabled or
disabled can be set using the Clear
signal setting.
17
+(+24 V) DC24V power supply input terminal
18
−(0 V)
This is the 0V terminal for DC24V
power supply and the control input
signal common terminal.
o
When using a control input connector, a separate DC24V
power supply is necessary for the control input circuit.
o
The control input signal is isolated from the unit’s circuits by
a photocoupler.
V
CAUTION
For terminals 17 and 18, use a power supply that conforms to
the limited energy circuit specification in IEC61010-1. Failure to
do so could cause fire or other hazards.
3-3-2. Connecting control input
terminals
Signals are input with the external input circuit when shorted
or opened between any control input terminal and the com-
mon terminal.
Shorts occur from both contact and non-contact (transistor).
9FF
í9
9
TD-SC1
External
power supply
DC +24V
PUSH switch
About 2 mA
Example when contact signal used
Example when transistor used
o
When external contact is ON, about 2 mA flows. When
using a transistor, for example, select one with a resistance
of at least 10 V and elements that allow a flow of at least
40 mA when on.
o
18 −(0 V) is the common terminal for the 11 IN (D/Z), 12 IN
(Hold) and 13 IN (Clear) control input terminals.
o
Do not apply voltage from an external source to a control
input terminal.
3. Making connections
