Board ReplacementSection 9-2

9-2-3 1:N NT Link Mode

Serial commu-

Indicator

Status

I/O memory

Cause

Remedy

nications

display

information,

 

 

 

mode

 

etc.

 

 

 

 

 

 

 

 

 

Serial commu-

---

---

Bits 12 to 15

Serial communica-

Set bits 12 to 15 (Serial

nications mode

 

 

(Serial Commu-

tions mode is not

Communications Mode) of

is not set to NT

 

 

nications Mode)

set correctly.

DM 6555/ DM 6550 to

Link.

 

 

of DM 6555/

 

5 Hex.

 

 

 

DM 6550 are

 

 

 

 

 

set to a value

 

 

 

 

 

other than

 

 

 

 

 

5 Hex.

 

 

 

 

 

 

 

 

Serial commu-

The COMMj

---

---

There is a hardware

Conduct a loopback test in

nications mode

indicators do

 

 

error.

serial communications

is set to NT

not flash at all.

 

 

 

mode to check the trans-

Link.

(Communica-

 

 

 

mission lines. If an error

 

tions have not

 

 

 

occurs during the test, re-

 

been electrical-

 

 

 

place the Serial Commu-

 

ly established.)

 

 

 

nications Board.

 

 

 

 

 

 

 

The SD and

---

---

There is a setting

Correct the PT serial port

 

COMMj indi-

 

 

error for the PT seri-

settings.

 

cators are

 

 

al port.

 

 

flashing, but the

 

 

 

 

 

 

 

The I:N NT Link unit

Review the NT Link unit

 

Serial Commu-

 

 

 

 

 

number of the PT is

number of the PT.

 

nications Board

 

 

 

 

 

incorrect.

 

 

cannot commu-

 

 

 

 

 

 

The same 1:N NT

 

 

nicate with the

 

 

 

 

Programmable

 

 

Link unit number

 

 

Terminal (PT).

 

 

has been set for

 

 

 

 

 

more than one PT

 

 

 

 

 

The maximum al-

Review the PC Setup set-

 

 

 

 

lowable NT Link unit

tings.

 

 

 

 

number is incorrect-

 

 

 

 

 

ly set for the sys-

 

 

 

 

 

tem.

 

 

 

 

 

 

 

 

 

 

 

Cables are incor-

Review the wiring or

 

 

 

 

rectly connected.

switch settings.

 

 

 

 

The RS-422A/485

 

 

 

 

 

port setting (2-wire

 

 

 

 

 

or 4-wire) is incor-

 

 

 

 

 

rect.

 

 

 

 

 

Adapters such as

 

 

 

 

 

the NT-AL001-E are

 

 

 

 

 

incorrectly wired or

 

 

 

 

 

set.

 

 

 

 

 

 

 

 

 

 

 

A communications

Review the wiring and

 

 

 

 

error frequently oc-

installation environment.

 

 

 

 

curs due to noise,

 

 

 

 

 

etc.

 

 

 

 

 

 

 

 

 

 

 

There is a PT hard-

Replace the PT.

 

 

 

 

ware error.

 

129

Page 137
Image 137
Omron CQM1H-SCB41 operation manual 3 1N NT Link Mode