Siemens 538-907 User manual

Installation Instructions
Document No. 588-097
Rev. 1, July, 2002
TTL/RS-485 Interface
Page 1 of 2
Product Description
The TTL/RS-485 Interface is a TTL to RS-485 trunk
interface. It converts two-wire TTL level signals into
RS-485 signals for the network controller. No
internal settings are required for communication
speed (bps). The TTL/RS-485 Interface operates at
any required trunk speed. The TTL/RS-485 Interface
is supplied with a 120 Vac Hz wall plug-in power
pack with a 6-foot (1.8 meter) CD power cord.
CAUTION:
Use only the plug-in transformer shipped
with this device.
Product Numbers
538-907 TTL/RS-485 Interface 115V
Required Tools
• Flat-blade screwdriver (1/8 inch blade width)
• Wire strippers
CAUTION:
Always wear an electro-static discharge
wrist strap and discharge accumulated
static before touching field panel
components.
Expected Installation Time
20 minutes
Prerequisites
To comply with installations requiring
Class 1 conduit connections, you may
mount the TTL/RS-485 Interface in a field
panel enclosure.
For Console Top Installation
• TTL source device in place; TTL cable
assembled and connected to source device
• Source of transient protected 120 Vac 60
Hz available
• Network controller installed and tested
For Wall-mounted Enclosure
• Enclosure mounted
• Transient protected outlet installed
• Network controller installed and tested
Installation
1. Connect the TTL cable between the RS-485
Interface and the TTL source device. See the
TTL Interface side of the TTL/RS-485 Interface
for circuit polarity.
2. Maintain proper fit. If the TTL trunk contains a
shield, cut it flush with the cable jacket or tape it
back.
3. Connect the RS-485 Interface terminals to the
network controller.
4. Maintain polarity between the network controller
and the RS-485 connections. The shield should
be landed on the network controller, but taped
back at the RS-485 Interface connections.
The network controller installation is now complete.

Document No. 588-097
Installation Instructions
Rev. 1, July, 2002
Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and
models as design improvements are introduced. Other product or company names mentioned herein may be the trademarks of their
respective owners. © 2002 Siemens Building Technologies, Inc.
Siemens Building Technologies, Inc.
1000 Deerfield Parkway
Buffalo Grove, IL 60089-4513
U.S.A.
Your feedback is important to us. If you have
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Document No. 588-097
Printed in the U.S.A.
Page 2 of 2
RS-485 TRUNK CABLE
(MAX 4000' / 1219.2 m;
STANDARD 24 AWG
LOW CAPACITANCE)
TAPE BACK
SHIELD
GROUND WIRE TO
EARTH (PN 538-583)
GW1011R1
POWER PACK
SMART TI-3 INTERFACE
(TTL/RS-485 INTERFACE)
SMART I, SMKI, OR
SMART II CONTROLLER
TTL-485 TTL-485
RS-485 INTERFACE
TERMINAL BLOCK
22 21
TTL-485
S-+S-+S-
-
+
+- +- +
12
SMVU-V
TERMINAL BLOCK
SMART I, SMKI, OR
SMART II CONTROLLER
TERMINAL BLOCK
22 21
SMVU-TI
+-+-
LOW
HIGH
LOW
HIGH
LOW
HIGH
Figure 1. TTL/RS-485 Interface Wiring Diagram.