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model 3000 DeviceNet Module Manual (DN311/DN311A)
Chapter 4 Operating Procedures for the DN311 (Software)
4
4.4.2 Confirming the allocations
(1) Function
Where in the input/output data areas of the DN311 the input/output data of a specified
slave device are allocated is calculated. Based on this allocation information, the
input/output data are read or written using an MREAD or MWRITE instruction.
(2) Diagrammatic representation (Function block)
P: Polling BS: Bit strobe
(3) Description of the function
(a) When REQ is TRUE, the allocations (top address and number of words) in the
input/output data areas of the slave device specified in terms of node under
management by the DN311 that is specified by CH, UNIT, and SLOT are
calculated and output.
(b) If the processing is not completed in 2 seconds or more due to an error or the
like, ERR and DONE are turned TRUE.
(c) Completion status is output to STATUS.
(d) If REQ is FALSE, both DONE and ERR turn FALSE.
(e) Keep REQ TRUE till DONE becomes TRUE.
Input Argument Output Argument
REQ BOOL type Execution enabled DONE BOOL type Completed
CH WORD type Channel No. ERR BOOL type Error
UNIT WORD type Unit No. STATUS WORD type Station status
SLOT WORD type Slot No. BS_ADD WORD type BS input data top address
NODE WORD type Node address BS_N WORD type No. of BS input data words
RPOL_
ADD
WORD type P input data top address
RPOL_N WORD type No. of P input data words
WPOL_
ADD
WORD type P output data top address
WPOL_N WORD type No. of P output data words
DN_INSTRUCT
CH
REQ
UNIT
NODE
SLOT
DONE
ERR
WPOL_ADD
RPOL_N
RPOL_ADD
BS_N
BS_ADD
WPOL_N
STATUS
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