User manual

Chapter 2 – Specifications

LT Series User Manual2–8

• This LT unit’s serial port is not isolated. To reduce the risk of damage to

the RS-422 circuit, it is important that you connect the SG/GND (Signal

Ground) terminals.

• FG and SG terminals are internally connected in the LT. When connect-

ing to another device, be sure to not create an SG shorting loop in your

system.

• Pin #14 (VCC) DC 5V Output is not protected. To prevent damage or unit

malfunction, use only the designated level of current.

Use the following instructions to create your own cable:

With the RS-422:

• The following pins must be connected in pairs, as follows:

#18 (CSB) <—> #19 (ERB)

#21 (CSA) <—> #22 (ERA)

• When connecting the RS-422 cable’s #9 (TRMX) and

#10 (RDA) pins, a termination resistance of 100 Ω is added

between the #10 (RDA) and #16 (RDB) pins.

• When making a cable for a Memory Link system, use a 4-

wire type of cable.

With the RS-232C:

• Do NOT use the following pins:

#9 (TRMX) #10 (RDA) #11 (SDA)

#15 (SDB) #16 (RDB) #18 (CSB)

#19 (ERB) #21 (CSA) #22 (ERA)

Connect the #1 (FG) terminal only if it is required by a con-

nected device.