Mitsubishi Electric Melsec Q Series User Manual page 122

4
FUNCTIONS
(2) Executing acyclic communication
Remark
4
- 13 4.2 PROFIBUS-DPV1 Functions
4.2.1 Acyclic communication with DP-Slaves
Execute the acyclic communication by the following procedure:
(a) Write the request instruction to be executed to the Acyclic communication request
area (Un\G23809 to Un\G24832).
(b) Turn ON (1) the bit corresponding to the request instruction No. in the Acyclic
communication request execution instruction area (Un\G23808).
(c) When the QJ71PB92V accepts the acyclic communication request instruction, the
acceptance status bit in the Acyclic communication request result area
(Un\G25120) turns ON (1).
(d) When execution of the acyclic communication is completed, the completion status
bit in the Acyclic communication request result area (Un\G25120) turns ON (1),
and the execution result is stored in the Acyclic communication response area
(Un\G25121 to Un\G26144).
POINT
When a communication fails in Class 1 services due to the following, being
exchanged with DP-Slaves may be initialized. (Inputs and outputs are turned OFF.)
• Cable fault, influence of noise (
• System switching occurred in redundant system
Especially, when this occurs in redundant system switching, outputs of the
relevant DP-Slaves momentarily turn OFF. Therefore, fully examine if the system
has no problem. (
For program examples on the acyclic communication, refer to the following:
• Single CPU system:
• Redundant system:
Sections 5.5.1 and 5.5.2)
Section 7.9.4)
Section 7.4
Section 7.9.4