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Design and Functions
9.3.1
Signalling Severe Errors
If a severe error (
12.3) occurs, the sensor head is intentionally blocked. All communication via the interface is
shut down. Such errors will be signalled by the LED
ERR
(channel A) and LED
TAPE
(channel B) to the user via a
sequence of 8 flashing impulses (short or long). A short flash impulse stands for a zero, a long flash impulse
stands for a one. The first impulse corresponds to the MSB, the last impulse corresponds to the LSB. The se-
quence is repeated after a 4 second break. You can find an example of such a sequence in Fig. 23.
If such a severe error occurs, the sensor has to be replaced. The flashing sequence codes support ELGO in
finding the exact cause for an error in case of necessary repairs.
Fig. 23: Illustrated example of an LED
ERR
flashing sequence, signalling a severe error
Table 2: Meaning of flashing codes due to severe errors
Flashing
code
Meaning
01h
02h
03h
04h
RAM test failed
05h
ROM test failed
06h
CRC check sum of code memory is not the same in both channels
07h
Stack test failed
08h
Undefined case in a multiple branch
09h
Test of CRC hardware failed
0Ah
Communication test between channels failed
0Ch
CPU test failed
0Dh
0Eh
Defective program sequence
10h
Channel assignment not unambiguous
11h
Position outside the allowed range
12h
Synchronization failed
20h
21h
Timeout during memory test
22h
Error in timer for timeout detection
40h
UART error
41h
42h
Invalid parameter
43h
Undefined exception
44h
45h
46h
Faulty position determination
47h
Parameter outside the allowed range
t [s]
0
2
4
6
8
10
12
14
16
18
20
22
off
on
0
0
0
1
0
0
1
0
LED
ERR
restart blink code
illustrated value 12
16
