Siemens 500 NIM User Manual
Page 46
Installation
3-11
SIMATIC TIWAY I Series 500 NIM User Manual
Lockout/Enable. Configuration switch 9 enables the P/C to “lockout” the
NIM during time-critical operations. This function is not needed normally.
During lockout, the NIM will not communicate with the P/C. The actual
mechanism is as follows:
1.
The P/C “sees” the NIM as an 8 channel discrete output module on the
I/O portion of the scan.
2.
If the P/C is to “lockout” the NIM during a time critical scan, it can set
the image register address that corresponds to the 8th output of the
module. If switch 9 of the NIM is set to one (to the left with module
installed) the NIM will not communicate with the P/C as long as the
8th output is turned on. To compute the address (A) of the lockout bit
within the P/C’s I/O range, use the following equation:
A ={64 * (B – 1) + [(S – 1) *8]+ 8}
where:
B — base number – 8 module base (1 based, no base #0)
S — I/O module slot number in base (1 based, no slot #0)
NOTE: This is not necessarily true for 520C and 530C controllers with high
density I/O configurations. Consult 520C/530C Hardware Reference Guide
(530–8108) for additional information on high density I/O configurations.
3.
In your Relay Ladder Logic (RLL) program, re-enable NIM to controller
communication by turning the output off after the controller is able to
resume communication with the NIM.
Transmit Delay or Key Delay. Configuration switch 10 provides a delay
of 500 msec following the receipt of Clear to Send (CTS) from a modem. This
delay may be required in radio modem installations to permit the
transmitter to reach full power before transmitting data. This delay is
activated when the key delay switch is set to 1 (positioned to the left).
There are three switches which are located above the Dipswitch banks and
are labeled “Reset” “Self Test” and “Local/Remote”. (Also, some older NIMs
have Local Line bias select switches.) Their functions are described in the
following paragraphs.
Reset. This switch is a momentary contact switch which initializes the
NIM and initiates the power-up self-test. This switch causes all indicators to
be on for approximately 1 second. Then all indicators, with the exception of
the TEST indicator, are extinguished for approximately 5 seconds. During
this time, the NIM runs a series of diagnostic tests to verify the hardware
components of the NIM.
Other Switches