Toshiba 2000 V Series Manual page 98

Chapter 4 Operating Procedures for the DN611 (Software)
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(4) Local node parameter (PARA_LOCAL)
PARA_LOCAL structure
PORT
LOCAL_ADR
POL_TRMODE
SCAN_INTERVAL
BGPOL_RATIO
RETR_CNT
TR_TIMING
Parameter
Port No. Set 0 fixed.
Local node address The same address as set with the rotary switches
Polling transmitting 0: A polling request is made to all slave devices, followed by waiting for
mode
1: Polling response is waited for after requesting polling to each slave
Scan interval wait time Specify a wait time for the next access to start after completing access
to all slave devices.
Minimum: 2 ms
Background poll ratio Devices for which background polling is specified (set with slave
parameters) are accessed at the scan interval set in poll ratio.
Example: If 5 is set, access is made every 5 scans. This parameter is
effective for both polling mode devices and bit strobe mode devices.
Retransmission counter Set 1 fixed.
Transmission timing A value for slave devices to detect transmission timeout if the DN611
doesn't access for a certain interval or more. Set a value greater than
the scan cycle of slave devices (usually, 100 ms or more).
• When a slave device with background polling is installed, set a value
• For synchronous mode communication, an interval longer than the
(5) Supplementary note on polling transmission mode
If a polling slave device returns no response in polling transmission mode, the DN611
may take different approaches to the problem.
(a) Polling transmission mode = 0
• The master device makes a polling request asynchronous with the response
of a slave device in polling mode, and waits for polling response from it for 20
ms after making the request.
After the 20 ms of waiting for its response, the DN611 starts the next scan.
• As long as there is a slave device which does not respond, the master device
waits 20 ms for response every scan.
• The real scan cycle in cases where there is a slave device which does not
respond is expressed as follows:
Real scan cycle = Real scan cycle in normal operation + 20 ms
WORD type
WORD type
WORD type
WORD type
WORD type
WORD type
WORD type
Table 4-13 Local Node Parameters
Description
batch polling response.
device.
Maximum: 10,000 ms
of time longer than (scan cycle x poll ratio).
transmission interval of the user program must be specified.
model 2000 DeviceNet Module Manual (DN611/DN611A)
Port No.
Local node address
Polling transmission mode
Scan interval waiting time
Background poll ratio
Retransmission counter
Transmission timing