1
! ALLOWS COMMUNICATIONS BETWEEN RS422 CONTROL
EQUIPMENT AND RLC PRODUCTS WITH 20 mA SERIAL
COMMUNICATIONS OPTION
! TRANSMIT DISABLE ALLOWS OPERATION ON A TWO-WIRE
BUS FOR RS485 COMPATIBILITY
! ISOLATED 20 mA SERIAL COMMUNICATIONS
! FULLY ENCLOSED SCREW TOGETHER DURABLE
PLASTIC CASE
DESCRIPTION
The GCM422 Serial Converter Module provides the capability of interfacing
Red Lion Controls products, with 20 mA current loop serial communications
option, to any equipment with RS-422 communications. The isolated 20 mA
current loop connections in the GCM422 allow multiple modules to be wired
into the serial loop. Data format of the RS-422 equipment must be the same as
the Red Lion Controls product (Reference the serial communications section of
the appropriate manual for more details). The GCM422 module can be made to
interface with RS-485 equipment by repositioning an internal jumper (which is
a removable plug type arrangement). (The user must supply a method of
electrically selecting the transmit disable input.)
An external power source is required to power the GCM422 module. Some
Red Lion Controls products have a +12 VDC output which can be used. (Note:
Reference appropriate manual to ensure +12 VDC output has enough current
capability.) The external power source and isolated 20 mA serial
communications loop connections are made via a 6 position terminal block
located inside the module. A 680Ω current limiting resistor is provided to obtain
the source current for the Serial Current Loop. Connections for the RS-422 or
RS-485 are made via a 25 pin female D-type connector.
SAFETY SUMMARY
All safety related regulations, local codes and instructions that appear in the
manual or on equipment must be observed to ensure personal safety and to
prevent damage to either the instrument or equipment connected to it. If
equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.
SPECIFICATIONS
1. POWER: +9 to 26 VDC @ 50 mA max. Power supplies must be Class 2 or
SELV rated.
2. RS-422 VOLTAGES:
Differential output voltage (pins 2 & 14): ±5 VDC
max.
under no load
condition.
Differential input voltage (pins 3 & 16): ±5 VDC
max.
mark condition = < -0.2 VDC
space condition = > 0.2 VDC
Common mode input voltage: -7 VDC to +12 VDC.
3. RS-485 TRANSMIT DISABLE INPUT (Pin 4):
Active low VIL= 0.8 VDC
max.
Internally pulled up to + 5 VDC through 3.3 KΩ resistor.
4. RS-422 DRIVE CAPACITY: Up to 32 RS-422 receivers connected in
parallel.
5. 20 mA CURRENT LOOP:
SO - Output Transistor Rating: V
max
= 25 VDC,
V
sat
= 1 VDC
max
@ 20 mA.
SI - Input Diode Rating: VF = 1.25 VDC
typ
, 1.5 VDC
max
@ 20 mA.
(Note: Reverse polarity protection at SI diode)
6. MAXIMUM CABLE LENGTH:
RS-422 or RS-485 cable: 4000 Ft.
20 mA current loop: 4000 Ft.
7. BAUD RATE: 9600 Baud max.
8. ENVIRONMENTAL CONDITIONS:
Operating Temperature: 0 to 50°C
Storage Temperature: -40 to 80°C
Operating and Storage Humidity: 85% max. relative humidity (non-
condensing) from 0°C to 50°C.
Altitude: Up to 2000 meters
9. CERTIFICATIONS AND COMPLIANCES:
SAFETY
IEC 1010-1, EN 61010-1: Safety requirements for electrical equipment for
measurement, control, and laboratory use, Part 1.
EMC EMISSIONS:
Meets EN50081-1: Residential, Commercial and Light Industry
CISPR 22 Radiated and conducted emissions
EMC IMMUNITY:
Meets EN 50082-2: Industrial Environment.
ENV 50140 - Radio-frequency radiated electromagnetic field
1
ENV 50141 - Radio-frequency conducted electromagnetic field
1
EN 61000-4-2 - Electrostatic discharge (ESD)
2
EN 61000-4-4 - Electrical fast transient/burst (EFT)
3
Notes:
1. For operation without loss of performance:
Install power line filter, RLC #LFIL0000 or equivalent.
I/O cables routed in metal conduit connected to earth ground.
2. Anti-static precautions should be observed before handling the device.
3. For operation without loss of performance:
Install power line filter, RLC#LFIL0000 or equivalent.
Refer to EMC Installation Guidelines section of the manual for additional
information.
10. DIMENSIONS:
0.99" (25.2 mm) H x 2.10" (53.4 mm) W x 4.32" (109.8 mm) L
11. Shielded cable must be used, connect shield drain wire to earth ground.
(Note: RS-485 Specifications are the same as RS-422)
MODEL GCM422 - SERIAL CONVERTER MODULE [RS422/20 mA current loop]
CAUTION:
Read complete instructions prior to
installation and operation of the unit.
Bulletin No. GCM422-G
Drawing No. LP0213
Released 2/05
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
www.redlion.net
ORDERING INFORMATION
MODEL NO. DESCRIPTION PART NUMBER
GCM422 Serial Converter Module RS422 GCM42201