HEIDENHAIN TNC 122 Technical Manual - Manual (Page 46)

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TNC 122 12 PLC Description 45
12 PLC Description
The TNC 122 features an integrated PLC for 15 inputs and 15 outputs. PLC programs for specific
machine models (see Chapter 10) have been prepared and stored by HEIDENHAIN in the EPROM.
If in rare cases the PLC program must be altered or rewritten, we recommend using the PLC.EXE
programming software, version 2.2 from HEIDENHAIN. This program can also generate the binary
code for the PLC EPROM (see the User's Manual for PLC.EXE).
The PLC program assigns fixed functions to the inputs and outputs at the X41 terminal block (see
Chapter 8 "Pin Layout."
In the TNC 122 the PLC program is run directly from the EPROM; there is no RAM memory for this
task.
For servicing purposes the logical status of the markers, inputs, outputs, timers and counters can be
transmitted through the RS-232-C/V.24 port to a computer. Transmission is activated by entering the
code number 807 667 in the TNC 122.
Under menu item "File/TNC 12x Monitor" the program PLC.EXE provides a function (PLCMONI.EXE)
for immediately displaying the logical status of operands, provided that the code number was
entered.
•  Use the rightward cursor key on the TNC to scroll through the markers.
•  Use the "R+/-" key on the TNC to scroll back through the markers.
•  Press the NO ENT key to leave the display.
12.1 PLC EPROM
The PLC EPROM is a 2-MB or 4 MB chip with 16-bit data organization. It is programmed in Motorola
format, which means that the most significant byte of a word is located at the first (lowest) address.
Addresses:
$00000
... $0000
...
$00400
$00402
$00403 PLC Program start address
Chip identifier (1 word)
PLC program length
$00405 $0000
$00406
...
$0041C
$0041E 10 th MP list
...
2
nd MP list
1 st MP list
$00420 $0000
$007E0 PLC Program in binary format
and
up to 10 machine parameter tables
$1C000 20 PLC error messages in 7 languages
20 dialogs in 7 languages (30 characters each)
$1FF00 PLC software number
$1FFFC Checksum
$1FFFE One's complement checksum