Справочник Пользователя для Siemens 500 NIM

Installation

The three levels of Series 500 NIM self tests available in the NIM are
described in the following paragraphs. They are:

•

Power-Up Self-Test

•

Run-Time Self-Test

•

User-Initiated Self-Test

 The Series 500 executes a Power Up Self-Test in the following cases:

•

Immediately following the application of +5VDC from the I/O base
(power-up) as part of its initialization

•

Any time the Reset switch is pressed (See Figure 3-3)

•

Following a Disconnect Secondary command from the host

The Power-Up Self-Test exercises the processor, performs a test of on-board
RAM and ROM, and performs an internal loopback test of the
communication ports. At the start of execution, all NIM indicators (LEDs)
are turned on for approximately 1 second, then all except the Test Mode
indicator are turned off for approximately 5 seconds.

If the Power-Up Self-Test is successful, the NIM GOOD LED will be on, and
an attempt to establish communication with a Series 500 controller will be
made. If this is successful, the PC/NIM COMM GOOD LED will illuminate
and the NIM is ready for normal network operation.

Failure of the Power-Up Self-Test will cause the Test Mode LED to remain
on, and the NIM will not respond to any commmunications attempts.

If the Series 500 controller does not respond, the PC/NIM COMM GOOD
LED will remain extinguished, and the NIM will issue an Exception
Response with Error Code 1A (communication not established with attached
device) to any host computer initiating a controller interactive command to
this NIM.

The Series 500 NIM monitors itself continuously during normal operation,
as follows:

•

The Operating System continuously performs a ROM integrity test as a
background operation.

•

The NIM periodically verifies that it is capable of communicating with
the Series 500 Sequencer.

•

A Watchdog Timer circuit in the NIM helps to guard against software
lockup.