INSTRUMENT MANUAL
VACUUM GAUGE MODEL MM200
160Phone:(215) 947-2500 fax:(215) 947-7464 e-mail:[email protected] web site:www.televac.com
MM-200_im REV M
Page 67 of 160
TELEVAC
602
RS232/485 - FOR SOFTWARE VERSION 2.31 OR HIGHER
The communications mode (RS232 / RS485) is now selected thru the front panel in setup. This is the last selection
when scrolling thru setup. To go directly to the communications setup, press the setup button, then press the
test/op button once. The following selection will appear,
RS232 or RS485
(use up/dn arrow to select)
Press setup button to advance to next selection or test/op to exit.
STD or ALT
(RS485 only)
(use up/dn arrow to select)
Press setup button to advance to next selection or test/op to exit.
UNIT #xx
(RS485 and STD only)
(use up/dn arrow to select)
Press setup button to advance to next selection or test/op to exit.
PREF #xx
(RS485 only)
(use up/dn arrow to select)
Press setup or test/op to exit.
In
STD
mode , a prefix and address must be selected for each instrument on the bus. If the same prefix is selected
for multiple instruments, then each of these must have a different address. A STD addressable command then
consists of a prefix, address, and command. The number of addresses available for the standard RS485 mode are
59.
In
ALT
mode the prefix is used as the individual address. Each instrument on the bus would use a different prefix.
This limits the number of slaves on a bus to 21. However, a unit on the bus would never be interrupted except
when it is addressed. The master would send the prefix for the unit it intended to address followed by the
command with no unit number required.