Datasheet

36 Remote I/O
SSI input unit
Item Specifications
Model NX-ECS112 NX-ECS212
Name SSI input unit
Number of channels 1 channel 2 channels
Input signals External inputs: 2 data input (D+, D–)
External outputs: 2 clock output (C+, C–)
I/O interface Synchronous serial interface (SSI), 2 MHz
Clock output EIA standard RS-422-A line driver levels
Data input EIA standard RS-422-A line receiver levels
Maximum data length 32 bits (the single-turn, multi-turn and status data length can be set)
Coding method No conversion, binary code or gray code
Baud rate 100 kHz, 200 kHz, 300 kHz, 400 kHz, 500 kHz, 1.0 MHz, 1.5 MHz or 2.0 MHz
Dielectric strength 510 VAC between isolated circuits for 1 minute at a leakage current of 5 mA max.
Insulation resistance 20 M min. between isolated circuits (at 100 VDC)
Isolation method Digital isolator
Unit power consumption 0.85 W max. 0.90 W max.
I/O power supply source Supplied from the NX bus. 20.4 to 28.8 VDC (24 VDC +20%/–15%)
Current consumption from
I/O power supply
20 mA 30 mA
Current capacity of
I/O power supply terminal
0.3 A max. per terminal
I/O refreshing method Free-run refreshing or synchronous I/O refreshing
*1
*1. The I/O refreshing method is automatically set according to the connected communication unit and CPU unit.
Terminal block type Screwless push-in terminal
12 terminals (C + D)
Screwless push-in terminal
12 terminals (C + D)
Dimensions (W x H x D) 12 x 100 x 71 mm
Weight 65 g
Maximum transmission distance
*2
*2. The maximum transmission distance for an SSI input unit depends on the baud rate due to the delay that can result from the responsiveness of the connected
encoder and cable impedance. The maximum transmission distance is only a guideline. Review the specifications for the cables and encoders in the system and
evaluate the operation of the equipment before use.
100 kHz (400 m), 200 kHz (190 m), 300 kHz (120 m), 400 kHz (80 m), 500 kHz (60 m), 1.0 MHz (25 m), 1.5 MHz (10 m) or
2.0 MHz (5 m)
Failure detection None
Protection None
C+
C-
IOV
IOG
D+
D-
IOV
IOG
NC
NC
NC
NC
Encoder
NX-ECS212
C1+
C1-
IOV
IOG
D1+
D1-
IOV
IOG
C2+
C2-
D2+
D2-
Encoder
Encoder
Terminal wiring
NX-ECS112
Circuit layout
NX-ECS112
D+
D-
C+
C-
120

No isolation: 5 V GND
No isolation: 5 V
No isolation: 5 V GND
Terminal block
No isolation: 5 V
I/O power supply +
I/O power supply

I/O power supply +
I/O power supply

NX-ECS212
D1+, D2+
D1-, D2-
C1+, C2+
C1-, C2-
120

No isolation: 5 V GND
No isolation: 5 V
No isolation: 5 V GND
Terminal block
No isolation: 5 V
I/O power supply +
I/O power supply

I/O power supply +
I/O power supply

Inter-
nal
cir-
cuits
Isola-
tion
cir-
cuit
Left-side
NX bus
connector
Right-side
NX bus
connector
Non-
isolated
power
supply
Inter-
nal
cir-
cuits
Isola-
tion
cir-
cuit
Left-side
NX bus
connector
Right-side
NX bus
connector
Non-
isolated
power
supply