Device Description HG G-7335xZA | English, Revision 05 | Date: 19.02.2020
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Chapter 8 – CAN Interface (HG G-73350)
8.2 Description of the Process Data Objects (PDOs)
8.2.1 Transmission Objects
The measured data are allocated to particular places in the PDO, a dynamical map
-
ping is not provided. The PDO mode can be set to cyclical, synchronous or a asyn
-
chronous. In order to prevent high bus load during the non-cyclical transmission
(asynchronous mode) the inhibit time in the CAN menu can be adjusted using the
serial monitor (see 7.3.3 on page 24). This is important as the constant changes may
affect the BUS. A PDO can be transmitted cyclical instead. The corresponding event
time is to be chosen accordingly and the inhibit time has to be set to 0.
A TxPDO can be deactivated permanently by choosing the asynchonous mode (255)
with inhibit time = 0, event time = 0 and saving of the parameters. Additionally, it can
be deactivated/activated temporarily by setting/deleting the highest bit in the corre
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sponding PDO-COB identifier [1800,01] or [1801,1].
8.2.1.1 PDO_1
PDO_1 is sent with the identifier 0x180 + node address. It contains 5 bytes in which
the displayed status on the serial monitor as well as two distance values (left-
aligned) are contained. The order of the transmission is status, X1, X2.
The order of the bytes within a 16bit word can be altered using point
from within
the CAN menu (see 7.3.3 on page 24) or the SDO with the index 0x2002,03 (Node
config).
The meaning of the status bits is determined as follows:
The interpreter works internally with a 16 bit signed integer
signed int16
to indicate
the deviation from the guide wire. The MSB (Most Significant Bit) is left-aligned, it is
indicating the algebraic sign: 1 for negative numbers, 0 for positive numbers.
Table 14
CAN: displayed numbers for PDO_1
Value Format
Value range
Annotation
Status unsigned 8 0..0xff
status bits according to Table 15
X1
signed 16
-32640…..+32640 -128 x 255 [mm]…..+128 x 255 [mm] *)
X2
signed 16
-32640…..+32640 -128 x 255 [mm]…..+128 x 255 [mm] *)
*) Hinweise zu der Umrechnung der Abstandswerte finden Sie underneath Table
15 below.
Table 15
CAN: meaning of the status bits
Bit no. Value Meaning
7
0x80
Us1 exceeds chosen threshold for channel 1
6
0x40
Us2 exceeds chosen threshold for channel 2
5
0x20
Toggle-Bit, changes its status after each transmission of PDO_1
4
0x10
calibration is active
3
0x08
DC monitoring Ud1 is OK
2
0x04
DC monitoring Ud2 is OK
1
0x02
not connected
0
0x01
Checksum of the EEprom - parameter is wrong.
