West Control Solutions KS98-1 - Manual (Page 193)

III-14.1 CPREAD (CAN-PDO read function (No. 88))
Function CPREAD is used for read access to instrument PDOs. Due to the normal quantity of min. 2 PDOs per instru -
ment, the data quantity of 2 PDOs 2 with 2 COB-IDs was grouped in one block.
Node address and COB-ID (CAN-OBject IDentifier) parameter setting is in the block. Moreover, node guarding for mon -
itoring the CAN communication to the specified node can be switched on.
Data provided by the instrument must be interpreted according to the instrument specification.
Groups of 4 transmitted bytes can be converted into different data types.
For this purpose, a conversion function for converting and inverting 1 to 4 bytes into a parameterizable data type (see
function AOCTET) is available.
Examples: R1+R2 > Int16 / R1+R2+R3+R4 >Long
a
Important note: The heart beat protocol is not supported. If an instrument can be operated only via “heart
beat”, the guarding function must be switched off.
Digital inputs:
start The function is active with the input not connected, or if start=1 is connected.
Digital outputs:
slotid
0 = module correct
1 = module wrong
et-err
0 = no engineering error
1 = no CAN-HW (KS 98-1 type) multiple node monitoring
id-err
0 = correct node id
1 = faulty node id or instrument does not reply specify own node ID as “NodeId”
no free receive PDOs (RPDO)
valid
Bit follows node status with the node guarding active
(0=”preoperational”, 1=”operational”) always 1 with node guarding switched off
Analog outputs:
R11 ...R1 8 1st to 8th analog input value in byte format (8-bit) for COB-ID 1
R21...R28 1st to 8th analog input value in byte format (8-bit) for COB-ID 2
Configuration parameters (can be changed only during OFFLINE):
NodeId CAN node address
Guard node guarding off/on
COBID1 decimal ID of the first CAN object identifier
COBID2 decimal ID of the second CAN object identifier
9499-040-82711 Description of KS 98-1 CAN bus extension
CPREAD (CAN-PDO read function (No. 88)) III-193