E2
MOUNTING
  Location 
Install the controller in a location that meets the following criteria:
• 
Common mode voltages of I/O except power supply and relay con-
tact output: The voltage to ground is 30Vr.m.s. max., 42.4V peak 
max., and 60V DC max.
• 
Neither high nor low temperature/humidity.
• 
Free from silicone gas and other corrosive gases such as sulfide gas.
• 
Little dust or soot.
• 
Protected from direct sunlight, wind or rain.
• 
Little mechanical vibration and shock.
• 
Not close to a high voltage line, welding machine or other source of 
electrical noise.
• 
At least 15 meters away from a high voltage ignition device for a boiler.
• 
No strong magnetic field.
• 
No flammable liquid or gas.
• 
Indoors
  Mounting Procedure
• 
The mounting must be horizontal within 10 degrees tilted in back side 
lowering or within 10 degrees tilted in back side rising.
• 
The mounting panel should be used with a thickness of less than 9mm 
of firm board.
  External Dimensions
 z C25  unit: mm
para
enter
display
mode
pv
out
sp
108
48
ot2ot1ev3ev2ev1man
SDC25
Mounting bracket
(Accessory)
Terminal
 z C26
mode
display
enter
para
man
ev1
ev2
ev3
ot1
ot2
sp
out
pv
Mounting bracket
(Accessory)
SDC26
108
96
 Handling Precautions
• 
To fasten this controller onto the panel, tighten a mounting 
bracket screws, and turn one more half turn when there is no 
play between the bracket and panel. Excessively tightening 
the screws may deform the controller case.
• 
Be sure to mount the unit in a panel so that operators do not 
touch the rear terminal block.
  Panel Cutout Dimensions
 z C25  unit: mm
30
min.
92
44
30
min.
 +0.5
 0
 +0.5
 0
(48×N−4)
92
 +0.5
 0
 +0.5
 0
 z C26
(96×N−4)
 +0.5
 0
92
 +0.5
 0
30
min.
92
30
min.
92
 +0.5
 0
 +0.5
 0
 Handling Precautions
• 
When three or more units are gang-mounted horizontally, the 
maximum allowable ambient temperature is 40°C.
WIRING
All wiring should follow local regulations and be carried out by certified and 
experienced personnel. Be sure to provide a switch within operator reach for 
shutting OFF the main power supply to the controller in the main supply wir-
ing. Also, in case of AC power supply models, the main supply wiring also re-
quires a time-lagged type (T) fuse (rated current: 0.5A, rated voltage: 250V). 
(IEC127) The following table 
shows the meaning of the sym-
bols in the terminal wiring label 
on the controller side:
 Handling Precautions
• 
Before wiring the SDC25/26, verify the controller’s model No. and 
terminal Nos. written on the label on the side of the body. Inspect all 
wiring once wiring work for the SCD25/26 has been completed.
• 
Use M3 crimp-type terminal lugs for wiring to terminal.
• 
Leave at least 50 cm between I/O signal wires and power wires. Do 
not put them in the same electrical conduit or duct.
• 
Be careful not to allow any crimp-type terminal lugs to touch adja-
cent terminals.
• 
To connect 2 (max.) crimp terminals to the same terminal screw, 
bend the crimp terminals beforehand.
• 
When the power to this controller is turned off, the current input 
circuit is cut off. If multiple current-input type SDCs are connected in 
series and you want to turn them on/off individually, convert them 
to voltage input by adding resistors (No. 81401325, sold separately) 
to the circuit.
• 
Prepare a heater current conductor to send a heater current through 
the current transformer. Do not use a heater current that exceeds the 
specified permissible current as this may damage the controller.
• 
The current transformer input cannot be used for phase control.
• 
There is no isolation provided between control output 1 and control 
output 2. Install an isolator as required.
• 
Do not connect a terminating resistor to either end of the RS-485 
communications line. Doing so may interfere with communication.
• 
Make sure that devices and equipment connected to this device 
have reinforced insulation suitable for the maximum operating volt-
age of this device’s power supply and input/output ports.
• 
The controller requires maximum 5 seconds to start up once the 
power is turned ON. The controller can be used once it has started 
up. However, it is recommended to allow a warm-up time of at least 
30 minutes to attain the specified accuracy.
 z Connection of C25/26
7
8
9
CT1
CT2
13
14
15
2
1
2
1
16
17
+
−
1
2
1
2
Digital input
RS-485
22
23
24
DA
DB
SG
18
19
20
21
3
4
5
6
3
4
5
6
2
1
2
3
1
COM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
10
11
12
10
11
12
10
11
12
+
−
+
+
−
mA
V
C
B
A
13
14
13
14
15
13
14
13
14
15
+
−
+
+
−
+
−
+
+
−
COM
3
2
1
4
Inputs
AC power supply
100 to 240 V AC
DC power supply
24 V AC/24 V DC
(non polar)
DI
Auxiliary output
Communication
Current
Relay
Event outputs
Relay
Relay
(independent
contact)
Current
inputs
DC current
DC  voltage
PV inputs
Thermocouple
RTD
Voltage pulse
Voltage pulse
Voltage pulse
Current
Current
Current
Symbols Meaning
AC power supply
DC power supply
Caution, there is danger of electric shock
Caution