Roland R1000 Series Manual page 86

Communication with the PLC
6.4.6 Service "Empty service"
The master initiates the service "Empty service" with the setting of the service selection. The
content of the index bytes IN1, IN2 and the application data bytes 0 to 3 are not relevant. The
checksum of byte 1 through 6 is calculated and inserted in byte 7. To initiate the service the master
switches the handshake bit. In order to avoid data faults the following sequence is compulsory:
1. Service selection, program index, parameter index, application data byte 0 to 3
2. Switch handshake
In addition consistent data communication from the master is necessary.
The R1000 checks the data with the checksum and mirrors the index adjustment in OUT1, OUT2
and the application data in OUT3...OUT6. A possibly set collision bit is set back. Only in the last
step inserts the R1000 the handshake bit in output 0.0 and indicates thereby that the data has
been completely accepted. The same sequence applies here also, in order to avoid data faults.
The slave should ensure a consistent data transmission.
6.4.7 Service "Reset parameter channel"
The service "Rest parameter channel" initiates the master by transferring a zero string. The service
was added for safety reasons during the start up of the system or in case a fault occurs in the bus.
The R1000 closes the parameters channel and mirrors "parameters channel closed" (38 00 00 00
00 00 00 00 Hex). The handshake bit remains set to 0. The collision bit is also set to 0.
6.4.8 Reset faulty access
For the following reasons a service cannot be executed:
• The current operating conditions do not allow the execution of the selected service.
• The collision bit in the management byte has not been reset.
• The index register address invalid parameters.
• The service cannot be applied to this parameter.
• The application data contains inadmissible values.
• The service is unknown.
The reasons above can prevent the service execution during reading or writing. The R1000
indicates this problem by the collision bit. In order to prevent an additional uncontrolled access
procedure, the R1000 expects the reset of the called service by the master. In addition the master
executes an "Empty service" with the confirmation of a handshake. After receipt of this empty
order, the R1000 puts the collision bit back and confirms the service with a handshake. Thus the
fault condition can be reset and the R1000 is available for further orders.
ROLAND ELECTRONIC GmbH · Otto-Maurer-Str. 17 · DE 75210 Keltern · Phone +49 (0)7236-9392-0 · Fax +49 (0)7236-9392-33
86
Double Sheet Detector R1000-series I20
with integrated fieldbus interface
If the service "Empty service" cannot be executed, the collision bit
Note
is et (remains set). In place of the application data a fault code is
transmitted, see section "6.4.8 Reset faulty access".
If the fieldbus is off-line the service "Reset parameter channel" is
Note
automatically executed.
If necessary the collision bit can be reset by the service "Close
Note
parameter channel" and by the service "Reset parameter channel".
However the parameter channel is thereby closed.
Manual
B0060191 / Rev. 1.7