Example Of External Wiring With The Ssi Encoder (Serial Communication) - Mitsubishi Electric MELSEC-L Series LD40PD01 User Manual

Example of external wiring with the SSI encoder (serial
communication)
Connect the flexible high-speed I/O control module to the SSI encoder using a shielded twisted pair cable of 0.2mm
thicker (24 AWG or larger). Make sure to check the SSI encoder specifications.
In addition, separately prepare an external power supply for the SSI encoder.
Flexible high-speed I/O control module
IN 0 (DATA input)
240Ω
820Ω
OUT 0 (CLK output)
Digital isolator
IO 5V
• Connect the DATA input to any of IN 0 to IN B.
• Connect the CLK output to OUT 0_DIF for SSI_Encoder_0, and to OUT 1_DIF for SSI_Encoder_1.
Relation between transmission speed and maximum cable length (reference value)
Transmission speed
100kHz
200kHz
300kHz
400kHz
500kHz
1MHz
1.5MHz
2MHz
The maximum cable length described in the above is a reference value. Depending on the response performance of the SSI
encoder to be connected, the maximum cable length may become shorter than the above description because a response
delay occurs.
Therefore, check the operation using an actual encoder to be connected, and use the module.
If the cable longer than the maximum length described above is used, the module becomes following states.
• An encoder value is fixed to an incorrect value and the module does not count the value correctly.
• An encoder value fluctuates and the module does not count the value correctly.
• An encoder value cannot be read and the module does not count the value correctly.
6.4 Example of External Wiring Between the Flexible High-speed I/O Control Module and an Encoder
Shielded twisted pair cable
IN 0_DIF
B18
IN 0_5V
A19
IN 0_24V
B19
270Ω 4.1kΩ
IN 0_COM
A18
OUT 0_DIF+
B4
OUT 0_DIF-
A4
SSI encoder
DATA output
+
-
CLK input
+
-
+
External +
power
-
-
supply
Maximum cable length
400m
190m
120m
80m
60m
25m
10m
5m
6 INSTALLATION AND EXTERNAL WIRING
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