2.5.5
COM 2 - RS-422
RS- 422 NOTE :
When used in RS- 422 mode, the trans mit ter must
be en abled via soft ware by set ting the RTS bit in the Mo dem Con trol Reg is ter (Bit 1).
2.5.6
RS-485 Mode Configuration
The RS- 485 muti-drop in ter face is sup ported on both se rial chan nels with the
in stal la tion of the op tional “Chip Kit” Win Sys tems’ part number CK- 75176-2. A sin gle kit
is suf fi cient to con fig ure both chan nels for RS- 485. RS- 485 is a 2- wire multi- drop in ter face
where only one sta tion at a time talks (trans mits) while all oth ers lis ten (re ceive). RS- 485
usu ally re quires the twisted line- pair be ter mi nated at each end of the run. The fol low ing
il lus tra tions show the cor rect jump er ing, driver IC in stal la tion, and I/O con nec tor pin- out
for each of the chan nels when used in RS- 485 mode.
2.5.7
COM 1 - RS-485
RS- 485 NOTE :
Be cause RS- 485 uses a sin gle twisted- pair, all trans mit ters are
con nected in par al lel. Only one sta tion may trans mit, or have its trans mit ter en abled at a
time. The trans mit ter en able/dis able is con trolled by Bit 1 in the Mo dem Con trol Reg is ter
(RTS). When set, the trans mit ter is en abled, when cleared (the nor mal state), the
trans mit ter is dis abled and the re ceiver is en abled. Note that it is nec es sary to al low some
mini mal set tling time af ter ena bling the trans mit ter bef ore trans mit ting the first
char ac ter. Like wise, fol low ing a trans mis sion, it is nec es sary to be sure that all
char ac ters have been com pletely shifted out of the UART (Check Bit 6 in the Line Status
Reg is ter) bef ore dis abling the trans mit ter to avoid chop ping off the last char ac ter sent.
021402
OPERATIONS MANUAL PCM-586
Page 2-5
WinSystems
- "The Embedded Systems Authority"
COM1 - DB9
PIN DEFINITIONS
U11 - Not Installed
U10 - Not Installed
U9 - Installed
3
o
2
o
1
o
J9
3
o
2
o
1
o
J11
Normal RS-485 operation is
achieved by jumpering J9 pins
1-2. For RS-485 with
Echo-back jumper pins 2-3
1 N/A
2 TX+/RX+
3 TX-/RX-
4 N/A
5 GND
6 N/C
7 N/C
8 N/A
9 N/A
COM2 - DB9
PIN DEFINITIONS
U8 - Not Installed
U7 - Installed
U6 - Installed
3
o
2
o
1
o
3
o
2
o
1
o
1 N/A
2 TX+
3 TX-
4 N/A
5 GND
6 RX+
7 RX-
8 N/A
9 N/A
J10
J8
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
