
Manual 37139C
UMT 1 - Measuring Transducer
© Woodward
Page 51/62
Framework Data for CAN Bus
Transmitting protocol ..........CAN (CiA)
Hardware .............................CAN bus
Transmission rate ................adjustable
Special characteristic ...........Bt0 = 03, Bt1 = 1C
Every 200 ms a data telegram of 8 bytes is sent, which is structured as follows (all word variables are in the high
byte / low byte format):
Transmission Data
ID ........................................Base ID s CAN number
Byte 1 ..................................Multiplexer [1 to 9]
Byte 2 ..................................always 221
Byte 3/4 ...............................1. data word (note table, no. 1), multiplexed (MUX = 1, 1)
Byte 5/6 ...............................2. data word (note table, no. 2), multiplexed (MUX = 1, 2)
Byte 7/8 ...............................3. data word (note table, no. 3), multiplexed (MUX = 1, 3)
Byte 9/10 .............................4. data word (note table, no. 4), multiplexed (MUX = 2, 1)
Byte 11/12 ...........................5. data word (note table, no. 5), multiplexed (MUX = 2, 2)
etc.
General
No IDs can be assigned twice in the system. This applies for all devices coupled to the CAN bus system. Likewise
all IDs set on the unit must be set to different values.
Procedure for base-ID transmission:
All units available in the bus system are assigned to the same "Base ID
transmission". The types of information are grouped in this way.
Example:
The base ID transmission = 800 is used with all units. The individual ID's are assigned to the various
unit numbers.
Unit number 1: ID = 801
Unit number 2: ID = 802
etc.
Procedure for base ID control:
The same procedure applies for base-ID control. (Standard value 224)