Siemens SIMATIC TI505 User Manual download pdf (Page 28)

Installation and Set-up

1-17

SIMATIC TI505/TI500 MODNIM User Manual

The

MODNIM monitors itself continuously during normal operation as

follows.

•

The operating system continuously performs a ROM integrity test as a

background process.

•

The MODNIM periodically verifies that it is capable of communicating

with the PLC.

•

A W

atchdog T

imer circuit in the MODNIM guards against software

lockup.

If any failures are detected in the ROM integrity test, the NIM GOOD

indicator light turns off and the MODNIM is forced into the failed state. In

this condition, the module goes into the Offline Mode and will not respond to

any requests. (See Figure 1-13.)

When the MODNIM is in its normal operating mode but fails to

communicate with the PLC, it reports this failure to the host computer with

an exception response. Error code 04 (failure in associated device) is sent,

and the PC GOOD (PC/NIM COMM GOOD) indicator goes out. (See

Figure 1-13.) If communication is re-established, the MODNIM returns to

normal mode and the PC GOOD indicator goes back on.

NOTE:

The first time a valid request is received, the ON LINE indicator

goes on and remains on as long as everything is operating properly

NIM

GOOD

XMT REC

LINE

TEST

NIM

GOOD

XMT REC

LINE

TEST

NIM

GOOD

XMT REC

LINE

TEST

ROM

Integrity Failure:

goes to Offline Mode

Not Communicating with

PLC: reports Error Code 04

All Run-time

tests OK

Figure 1-13 LED

Status during Normal Run-T

ime Operation

The W

atchdog T

imer circuit provides an extra measure of protection against

network lockup due to a failed MODNIM. This circuit will force a RESET if

the operating software fails to execute normally

Run-time Self T

ests

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 ... 90 91

Comments to this Manuals

No comments

Siemens SIMATIC TI505 User Manual Page 28

Comments to this Manuals