Festo EMCA-EC-67 CO Series, Description

Page: 227 / 416

A Festo Parameter Channel (FPC)
Festo – EMCA-EC-C-HP-EN – 2017-11e – English 227
A.3.3 Sequence of parameter transmission
Parameter transmission takes place in the following sequence:
1. Start transmission.
2. Wait until the “Transmitting parameters” acknowledgment is made.
3. Wait between 2 successive jobs, send task identifier 0 (no job, “zero request”) and response identi­
fier 0 (no reply).
This ensures that an “old” response is not interpreted as a “new” response.
Parallel to the transmission, the controller must evaluate possible errors.
Before and after the parameter transmission, the telegram “no job” is exchanged cyclically between the
controller and EMCA.
Written parameters must be permanently stored by writing PNU 127:2 with the value 1 so
they will be secure in case of power failure.
A.3.4 Example: transmitting parameters
Write parameter PNU 440.02 with 4660
d
FPCC = 0001 1000
Sub-index = 0000 0010
Parameter number = 0000 0001 1011 1000
User data = 0000 0000 0000 0000 0001 0010 0011 0100
Parameter successfully written
FPCS = 0001 0101
Sub-index = 0000 0010
Parameter number = 0000 0001 1011 1000
User data = 0000 0000 0000 0000 0001 0010 0011 0100
controller
EMCA
Fig. A.1 Example: parameter transmission sequence
A.3.5 Error codes
Errors are reported in the FPCS and the error code is transmitted in the user data.
Error code Error
0 0x00 Invalid PNU
1 0x01 Parameter value cannot be changed.
2 0x02 Lower or upper value limit is exceeded.
3 0x03 Faulty sub-index
11 0x0B No supervising access
17 0x11 Job cannot be carried out in the operating status.
101 0x65 Festo: ReqID is not supported.
102 0x66 Festo: Parameter is write-only.
Tab. A.7 Error codes in parameter transmission