Hitachi NJI-350B manual Sequence, 11-7

Chapter 11 Communication Specifications

(3)Sequence

An example of a communication sequence using the Omron-made modem ME3314A is given below.

(a)Reception sequence

2]

DR on

0

CR

Modem

1]

MICRO-EH

ATE0Q0V0&C1&S0

CR

LF

ER on

Initial setting (Note 1)

Waiting for reception

2

CR

2

CR

2

CR

Modem

MICRO-EH

3]

Forced connection when three rings are detected

1

CR

Modem

4]

MICRO-EH

ATA

CR

LF

Port communication begins from here

Reception complete

1] The PLC issues the AT command that performs the initial setting of the modem.

2] If initial setting is OK, the modem returns “0.”

3] The PLC detects the result code “2” three times while in the reception wait state.

4] It connects the modem.

(b)Disconnect sequence

Modem	3	CR
	Port communication ends	1]
MICRO-EH
		Line disconnected

1] The PLC disconnects the line when the result code “3” is returned from the modem.

Note 1: Since the modem initial setup sets only minimal items from the MICRO-EH side, connect a personal computer and perform necessary settings before making the connection. (Set the DR signal to always on.) Moreover, do not change the following initial settings.

Contents of the initial settings

Command echo:	None
Result code:	Yes
Display format of result code:	Numerical format

Note 2: The modem timeout (WRF03C) stored in the special internal output refers to the time from data transmission from the MICRO-EH to the data reception from the opposite station (STX, ENQ, NAK). Normally, this special internal output should be set to “0000” (default) or “H8000” (no timeout). Set the timeout only when it is especially necessary to monitor the reception time from the opposite station. When a timeout is detected, the MICRO-EH cuts off the line. When setting the timeout, set the time in the ** part of H80. The unit is * seconds (hexadecimal).

Note 3: Before actually cutting off the line, issue the task code of the line cut off request (HIC--see Appendix 2, “Task code list” for details) from the host side.

11-7