MULTIPORT ELECTRONIC CONTROLLER continued...

D.COMMUNICATIONS

1.ASCII BASED PROTOCOL/RS-232 CONNECTION

The standard communications protocol for the MEC uses a simple ASCII format which connects the host device (computer, RTU or PLC) through jumper selectable connection. Refer to board drawing on page 18 for the jumper location, jumper ‘A’ for RS-232.

The external host device sends commands through a RS-232 cable to the electronic controller at 1200 baud with 8 bits, no parity and one stop bit. The following is a list of commands and responses. The CPU chip is labelled "STD".

NOTE:

In the following table the '<cr>' is the ASCII character #13 (0x0d).

 

 

 

 

 

?<cr>

 

Request status

 

apo<cr>

Response where:

 

 

 

a =

'R' for REMOTE selector setting, or

 

 

 

 

'J' for JOG selector setting, or

 

 

 

 

'S' for STEP selector setting

 

 

 

p =

position '1' to '8'

 

 

 

o =

'O' for 'on' position, or

 

 

 

 

'F' for 'off' position

 

!p<cr>

Go to position where:

 

 

 

p =

position '1' to '8'

 

a<cr>

 

Response where:

 

 

 

a =

'R' for REMOTE selector setting, or

 

 

 

 

'J' for JOG selector setting, or

 

 

 

 

'S' for STEP selector setting

 

$pt<cr>

Write valve position message where:

 

t<cr>

 

p =

position '1' to '8'

 

 

 

t =

text message up to 16 characters

 

 

 

 

 

#<cr>

 

Request status using 'text' response

 

t<cr>

 

Response where:

 

 

 

t =

text message for position of valve

 

 

 

 

@<cr>

Request list of disabled positions

 

dddddddd<cr>

Response where:

 

 

 

d =

number of active position '1' to '8'

 

 

 

 

(if a position is disabled, a '-' will be in that

 

*h<cr>

Set the Home position

 

a<cr>

 

Response where:

 

 

 

a =

'R' for REMOTE selector setting, or

 

 

 

 

'J' for JOG selector setting, or

 

 

 

 

'S' for STEP selector setting

Optional software is available for personal computers in DOS, Windows 3.11, or Windows 95 versions.

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