Filter
Top Products
3
WATLOW Series 945
How to Use Data Communications
This manual is a supplement to the Series 945 User's Manual. It is for users with
the data communications option. Use in conjunction with the Series 945 User's
Manual.
This is expert user-level material and requires previous experience with data
communications.
Two Serial Hardware Interfaces and
Two Software Protocols
Depending on your units model number, you may have one of two hardware
interfaces:
1)RS-422A for a "multidrop" or (multiple device) network, up to ten devices total;
with 4000 ft. network length limit, or RS-423A (RS-232C compatible) for one on
one communication with a 50 ft. network length limit with a 945 and a host
computer (945A-XXXX--B000). Selecting RS-422A or RS-423A is user select-
able via internal switches. See Page 7.
2)EIA-485 (945A-XXXX-D000) also for a multidrop network, up to 32
addresses total, and with a 4000 ft. network length limit.
There are two protocols available to you. Depending on the type of 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 and EIA-485 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 will also work with the RS-422A and EIA-
485 interface, but the network is limited to two devices (one computer or printer
and a Series 945). XON/XOFF Protocol requires no responses to messages like
the ANSI X3.28 Protocol does. 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 one Series 945 and a host computer or printer.
To select which protocol you are going to use, go into the SETUP menu and use
the MODE key to advance to the Prot parameter. Select either FULL, for ANSI
X3.28 2.2 - A.3, or On for XON - XOFF.
If you are using ANSI X3.28 Protocol, choose an address number for the control
under the Addr parameter following the Prot parameter. This parameter will only
appear if Prot = FULL.
Communications Wiring
To connect your Series 945 to a computer or printer, use the next three pages as a
reference. Your computer or printer hardware manual will provide more detailed
serial port pin information. Also refer to the noise prevention section in Appendix 1
of the Series 945 User's Manual. In the often noisy environments of industrial
locations, it is important not to take noise isolation lightly.
How to Use Data Communications
with the Watlow Series 945
Data Comm