Chapter 9: Message transfers

[5] Two-layer communication with the Ethernet

In order to communicate with the Ethernet on a different layer, use the following information in the communication format header (see page 9-19) as an extension header.

 

 

 

Host computer

 

 

0

 

00(H)

 

 

 

 

 

 

1

 

00(H)

 

 

 

2

 

00(H)

 

 

 

3

 

00(H)

 

PSA

 

4

 

PDA

 

Ethernet

 

5

 

PSA

 

 

 

6

 

FT0

PC

 

 

7

 

PO0

40 bytes

 

 

8

 

EA1

PDA

PO0

 

9

 

FT1

(JW-255CM)

 

 

(JW-20FL5/20FLT)

 

 

 

 

 

 

 

 

00(H)

 

 

 

39

 

 

 

PC

 

 

 

FL-net

 

 

40

 

 

 

 

 

 

 

 

 

 

 

Command line

 

EA1

 

 

 

 

(JW-20FL5/20FLT)

 

 

 

 

 

 

 

 

 

[An example of using the JW-20FL5/20FLT]

 

 

 

 

9

- When making a two-layer communication with the FL-net, the frame needs to contain the information

including the source, transit stations, and destination, and slot number (i.e. designating the communi-

 

 

cation path). The FL-net uses eight bits to represent a station number. For that reason, when designat-

 

ing a module on the Ethernet, a station number for the FL-net needs to be designated. The address is

 

referred to as a pseudo station number.

 

 

(a) PDA

: Pseudo destination address

 

 

 

 

Designate the station number of JW-255CM that connects with the Ethernet. This

 

 

 

may be any value within the range of 1 to 254 that can be discriminated from other

 

 

 

equipment on the Ethernet.

 

 

(b) PSA

: Pseudo source address

 

 

 

 

Designate the station number for the equipment sending the command. This may be

 

 

 

any value within the range of 1 to 254 that can be discriminated from other

 

 

 

equipment on the Ethernet.

 

 

 

 

With respect to the response, the pseudo target station number that is given by the

 

 

 

command will be set.

 

 

(c) FT0

: Frame type 0

 

 

 

 

Designate 60(H).

 

 

(d) PO0

: Transit slot number

 

 

 

 

Designate the slot number on the transit station PC that the FL-net module JW-

 

 

 

20FL5/20FLT is installed on. This number is 2, 3 ... up to 7 from the next position of

 

 

 

the control module (in case ZW-6CC is used.)

 

(e) EA1

: End target station address

 

 

 

 

Designate the end target station address 1 to 254 on the FL-net.

 

(f) FT1

: Frame type 1

 

 

 

 

Set the 40(H).

 

 

(g) Command line : Command/response line

c-ID/r-ID and after of communication format (page 9-19)

9-43