Toshiba S20LP instruction manual Scan transmission overview

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6 F 3 B 0 3 5 6

2. Scan transmission overview

The Scan transmission method is suitable for real time control data linkage.

In the S20LP, data sending station is rotated cyclically. Each station has common memory for Scan transmission. The size of the common memory is 4096 words. When a station becomes the data sender station, it sends data of prespecified area of the common memory. All other stations receive the data, and store them into their common memory. Therefore, the common memory in each station is totally updated in a transmission cycle.

The common memory is allocated to the Link register (W) in the T2N/T3H. The size of the link register is 2048 words. The link register is a part of common memory. By simply reading/writing data from/to the Link registers, high speed data linkage is achieved.

S20LP

T2N STN

Common

memory

(1)

Send

(2)

Receive

(3)

Receive

T2N’s Link

register

Write

Read

T2N STN

Common

memory

(1)

Receive

(2)

Send

(3)

Receive

T2N’s Link

register

Read

Write

Read

T3H STN

Common

memory

(1)

Receive

(2)

Receive

(3)

Send

T3H’s Link

register

Read

Write

Note 1) The data send block(s) of each station is prespecified by using the S-LS.

Note 2) Data transfer between common memory and Link registers is executed by T2N/T3H's OS. The transfer direction (read or write) is automatically decided.

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Contents T2N/T3H stations Important Information Preface Contents Introduction to S20LP System configuration∙ Overview Station hardwareT2N include of S20LP Port SN325 SN325S20LP port for T2N PU245N ∙ Status LEDsFor SN325 ∙ Transmission cable connectors ∙ Station number setting switches∙ Reset switch only SN325 ∙ Loader portMenu LS overview⎯ 10 ⎯ S20LP system specifications SpecificationsS20LP-station specifications Scan transmission overview Allocation and network assignment by T-PDS Setting the data send block by S-LSStation number setting Setting for data linkageSettings on T-PDS Link PDS screen example Block Send Receive ⎯ 18 ⎯ Global ⎯ 20 ⎯ Settings on S-LS ⎯ 22 ⎯ ⎯ 23 ⎯ ⎯ 24 ⎯ ∙ Start with Standby mode ∙ Scan Access∙ Scan Transmission ∙ Message Transmission∙ Target Scan Time Data linkage example ∙ Settings on T-PDS Setting on S-LS LS setting screen 2 for STN #2 Cable connections Behavior in trouble RAS function∙ Station down ∙ Transmission cable breakageAt initialization at power on Self-diagnostic functionDuring operation SN325 LED indicationT2N RAS information monitored in T2N/T3H Online map Station statusLoop map Only T2N Standby mapNumber 1-64 on the screen shows the Station number RAS information monitored on S-LSSelf Station Station No.01 Offline Select the Station Number Click the Status Display Station down information Possible error message are as followsExpanded data transfer instruction Instruction SpecificationInstruction format FunctionTransfer parameter table Parameter and construction∙ Operation Sample programRemarks Message transmission Message transmissionComputer link protocol PC link protocol∙ Send CMD Transfer parameters aStatus B TermSTS Status Meaning Detailed Information Send completion status Transfer parameters PC link protocol transmission Data writeRID Important items Status See 7.3 5 for details on bits C, D, E, and FXW/YW PC link protocol transmission Data read ⎯ 57 ⎯ SW067 Write enabled Remarks PC link protocol transmission programLength END Scan cycle Appendix⎯ 63 ⎯ PDS remote programming PDS Setup options screen