Watlow Series 1500 - Manual (Page 61)

Data Communications,
Commands and Syntax
In this section you’ll learn the Series 1500 data communications. See Figure 14 in
Chapter 1 for RS422 and RS423 pin designations, and also for locating and
making the required RS422/423
jumper selection.
The Series 1500 data communications package provides you with a foundation for a
sophisticated communications system based on your system needs and your soft-
ware development. Your Watlow Sales Engineer has available, upon request, a
Series 1500 data communications sample computer program with sample profiles.
Communication Parameters
The Series 1500 with data communications operates with these parameters.
Baud Rate: 1200 Baud
Character Format:
7 Data Bits
Stop Bits: 1 Stop Bit
Parity: Odd Parity
Protocol
You can select one of two hardware interfaces:
1) RS422A for a “multidrop” or (multiple device) network, up to ten devices total;
with 4000’ network length limit, or
2) RS-423A (RS-232C compatible) for one on one communication on a 50' network
you
need, you must use the correct combination of interface and protocol.
We use ANSI X3.28 Protocol, based on ANSI X3.28 - 1976 Subcategories 2.2, and
A3, with the RS-422A
interface to run a multiple device network We also use XON/
XOFF Protocol, a simpler protocol, to run a two device network with an RS-423A
interface. XON/XOFF Protocol requires no
responses
to messages like the ANSI
X3.28 Protocol does.
XON/XOFF will also work with the RS422A interface, but the
network is limited to two devices. Likewise, ANSI X3.28 Protocol, which provides a
response to every message, will work with the RS-423 interface. But again you are
limited to two devices.
Data Communications, Commands and Syntax, Chapter 4 WATLOW Series 1500 User's Manual 61