TM 5-3895-374-24-2
955-257
SECTION 5-DIGITAL COMMUNICATIONS
5.1 COMMUNICATIONS IDENTIFICATION
The specific type of digital communications circuitry provided in the controller is indicated by the second digit of the ten
digit part number.
MODEL 2001
MODEL 2002
MODEL 2003
MODEL 2004
TYPE
E0-
Z0-
EA-
ZA-
No digital communications
E1-
Z1-
EB-
ZB-
No digital communications
E2-
Z2-
EC-
ZC-
RS232C non-isolated
E3-
Z3-
ED-
ZD-
RS232C isolated
E4-
Z4-
EE-
ZE-
RS422 non-isolated
E5-
Z5-
EF-
ZF-
RS422 isolated
E6-
Z6-
EG-
ZG-
20mA Current loop isolated
The communications circuitry is located on the middle circuit board of the electronic assembly. This board plugs into
the front bezel assembly and connects to the rear "D" connector by means of a flexible flat ribbon cable that plugs into
the bottom edge of the communications circuit board.
5.2 COMMUNICATIONS CONNECTOR
The "D" Type (DB25S) 25-PIN digital communications connector located at the rear of the controller is a standard
Electronic Industries Associates (EIA) interface for RS232C. RS422 and 20 mA current loop use the same connector.
Wiring to the controller is identical to that for any Data Terminal. The following table identifies each connector pin by
function. Sections 5.55.7 specify the specific wiring for the three available interfaces.
5.3 CONNECTOR PIN DESIGNATIONS
PIN
MNEMONIC
SIGNAL
DESCRIPTION
1
GWG
Protective
In the RS232C environment this line provides a
Ground
ground connection between devices. Although not
required, may also be used for RS422 and 20 mA
current loop configurations for the same purpose.
2
TX
Send
Transmits data within RS232C voltage levels
Data
(+12V and-12V) or RS422 voltage levels (0 and
5V differential). Also used by the 20 mA
current as 20 mA input (user supplied) for the
transmit loop.
3
RX
Receive
Accepts data within RS232C or RS422 voltage
Data
levels or used by the 20 mA current loop as 20
mA input (user supplied) for the receive loop.
4
RTS
Request
This line is normally held inactive by the
to Send
controller until a message is ready to be
sent. Then the line is switched active and
the controller waits for the clear to send.
ECLIPSE INSTRUMENTATION DIVISION
page 3-1104
