Clear-Com PS-232 Instruction Manual

PS-232

2-CHANNEL POWER SUPPLY

INSTRUCTION MANUAL



2002 Clear-Com Intercom Systems

All Rights Reserved

Part Number 810277 Rev. A

Clear-Com Intercom Systems
4065 Hollis Street
Emeryville, CA 94608-3505
U.S.A

Clear-Com is a registered trademark of Clear-Com Intercom Systems.
The Clear-Com Logo is a registered trademark of Clear-Com Intercom Systems.

Clear-Com PS-232 Power Supply

IMPORTANT SAFETY INSTRUCTIONS

1 Read these instructions.

2 Keep these instructions.

3 Heed all warnings.

4 Follow all instructions.

5 Do not use this apparatus near water.

6 Clean only with dry cloth.

7 Do not block any ventilation openings. Install in accordance with the manufacturer's

instructions.

8 Do not install near any heat sources such as radiators, heat registers, stoves, or other appara-

tus (including amplifiers) that produce heat.

9 Do not defeat the safety purpose of the grounding-type plug. A grounding type plug has two

blades and a third grounding prong. The third prong is provided for your safety. If the provided
plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

10 Protect the power cord from being walked on or pinched, particularly at plugs, convenience re-

ceptacles, and the point where they exit from the apparatus.

11 Only use attachments/accessories specified by the manufacturer.

12 Unplug this apparatus during lightning storms or when unused for long periods of time.

13 Refer all servicing to qualified service personnel. Servicing is required when the apparatus has

been damaged in any way, such as if the power-supply cord or plug is damaged, liquid had
been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain
or moisture, does not operate normally, or has been dropped.

14 Do not expose the apparatus to to dripping or splashing and do not place opjects filled with liq-

uids, such as vases, on the apparatus.

WARNING
or moisture .

: To reduce the risk of electric shock, do not expose this apparatus to rain

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Clear-Com PS-232 Power Supply

QUICK START

1 Unpack the unit and inspect for any damage that may have occurred in shipping. Connect the

proper AC Mains cable to the outlet on the rear panel.

2 Install the PS-232.

3 Connect the intercom lines and Program Input as required. Connect the AC cord to the Mains

circuit.

4 Set the two termination switches on the rear panel to ON.

5 Switch the Power ON. The green power light should be ON and the two red overload lights

should be OFF.

6 Switch the Test Tone and A+B Link switches OFF. The yellow A+B Link light should be off.

7 Select program sends and set program levels as required using Program Trim and Program

Send Level controls.

8 Set levels and sidetone nulls at remote stations.

9 The intercom system should now be operating properly.

10 Read the rest of this manual for further information.

OPERATION

Congratulations on choosing this Clear-Com product.

The PS-232 Power Supply is a powerful, yet user friendly unit that can serve as the heart of a Clear­Com system.

We recommend that you read through this manual completely to better understand the functions of the
PS-232 and how to optimize your system setup. Please pay particular attention to the section on sys­tem wiring, as improper wiring detracts from the performance of the system or causes system failure. If
you encounter a situation or have a question that this manual does not address, contact your dealer or
call Clear-Com direct at the factory. Our applications support and service people are ready to help.

Description

The Clear-Com PS-232 is a single rack space, one- or two-channel intercom power supply which can
provide 1 amp (2 amps peak during call signals and other temporary events) at 30 Volts DC to operate
Clear-Com beltpacks and remote stations. This power is supplied to either or both channels, and will
support up to 40 headset stations or 15 speaker stations. Clear-Com's advanced fail-safe design can
sense the difference between a short or an overload to optimally protect itself. Power is restored in as
quickly as 1/2 second, depending upon whether there was a single or multiple short or overload. The
other channel continues to operate normally. The PS-232's advanced fail-safe circuit will bring the
power back up even under full load conditions. LED indicators signal a fault on either channel. A line­level program input offers a master input level. Individual program selects, each with its own send level,
are provided for each channel. Use of a switching power supply allows the PS-232 to operate with
any AC line voltage from 90 to 240 Volts AC at 50 or 60 Hz. The unitized aluminum chassis and extra­thick front panel with integral rack ears result in reduced size and a lighter weight package that main­tains legendary Clear-Com ruggedness.

Advanced Fail Safe Power Scheme

As the heart of an intercom system, the power supply has special needs which are not met by traditional
designs. It must work in adverse conditions such as low AC line voltage, momentary or continuous

2

Clear-Com PS-232 Power Supply

shorts on the DC power lines to the stations, and excessive peak loads during power-on and sometimes
during use. The mission of an intercom power supply is torn between giving its all to provide power in
the face of these adverse conditions and protecting itself from them. This mission finds an intelligent
balance in the PS-232. The following features are incorporated into the PS-232 power supply to make it
quickly react to shorts and overloads yet provide a long, reliable product life:

AUTOMATIC SHORT CIRCUIT PROTECTION: The microprocessor in the PS-232 checks each
channel for a short or current overload 100 times per second. If a short lasting longer than 700 mS
is detected, the microprocessor will shut down that channel. An short lasting less than 700 mS will
not cause the PS-232 to interrupt power. However, during this 700 mS, the output current will be
limited to 2 amperes.

AUTOMATIC OVERLOAD PROTECTION: The PS-232 senses the difference between shorts and
overloads. If an overload lasting longer than 2.5 seconds is detected, the microprocessor will shut
down that channel. An overload lasting less than 2.5 seconds will not cause the PS-232 to interrupt
power. During this 2.5 seconds, the output voltage will be reduced to limit the current to 2 amperes.

AUTOMATIC POWER RESTORE: The PS-232 microprocessor senses the difference between
short-term and long-term shorts and overload conditions. After the first few times a short or overload
occurs the PS-232 will try to restore power after only 0.5 seconds. If the short or overload persists
or repeatedly happens, the microprocessor will take progressively longer (to a maximum of 20
seconds) to try to restore power. This protects the PS-232 from damage due to overheating. Once
the short is removed, the channel will recover, even under a full load condition. The automatic
power restore times are shown in the following chart:

20

Number of

Seconds to

Restore

20

15

10

7

5

0.5

0

2 4 6 8 101214161820

135791113151719

0

4

2

Number of Recent

Shorts or Overloads

14

INDIVIDUAL CHANNEL SHORT CIRCUIT PROTECTION: Each individual channel is separately
overload and short circuit protected and may draw as much as 2 Amps, though the total to both
channels is limited to 2.25 Amps. A short on any one intercom line will not bring the whole system
down.1

FRONT PANEL INDICATIONS: There are two Overload indicators on the front panel (one for each
channel) and a Power indicator for the power supply. The Overload indicators light steady when an
overload or short condition is detected. They blink if power to a channel has been shut off as a
result of an overload or short. There is also an indicator to show when channels A and B are linked.

PARALLELING MULTIPLE POWER SUPPLIES: Multiple power supplies can be paralleled to
increase system capacity. The PS-232 microprocessor will automatically detect the actions of other
power supplies during overloads and shorts circuits to restore power as quickly as possible.

1 Power supply lines connected together at remote stations will disable the individual channel short

circuit protection feature.

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Clear-Com PS-232 Power Supply

MULTI-CHANNEL REMOTE STATIONS MAINTAIN THE POWER LINE ISOLATION: The RM-220,
KB-211, and MR-202 as well as any two-channel remote stations or beltpacks are designed to use
the isolated power provided by the PS-232. Refer to the INSTALLATION section.

LOW NOISE CIRCUITRY: The direct current outputs of the PS-232 contain very little hum and
noise. The PS-232 does not contribute to audible noise in the remote stations and beltpacks.

FRONT AND REAR PANELS

A description of the connectors and controls follows. Refer to Figure 1.

24 37 5 6 1

8109

Figure 1

Front Panel

1 POWER SWITCH: Turns the AC power to the PS-232 on and off. The green Power light will

illuminate when the power is ON.

2 OVERLOAD INDICATORS: If a short circuit or overload condition appears on either of the

intercom channel outputs, the red Overload light for that channel will illuminate. If this
condition persists, the microprocessor will disconnect power to that channel and the red
Overload light will blink. If a red Overload light is blinking, the fault on that channel must be
located and removed. When the fault is removed, the PS-232 will restore power to that
channel and the Overload light will go out . If there are no shorts, but the Overload light blinks,
an overload exists, possibly due to too many intercom stations connected on that intercom line.

If the failure continues, unplug the intercom line connected to the affected channel. Its red
Overload light should go out. This indicates a short in that line. Follow that intercom line
connecting and disconnecting cables along the line until the fault is isolated.

1112

3 PROGRAM SEND ON/OFF: These toggle switches, one for each channel, connect program

audio to each channel. Both channels receive the same signal from the rear panel PROGRAM
INPUT. The number of active sends will not affect the overall send level to any channel.

4 PROGRAM SEND LEVEL: These controls (one for each channel) adjust the level of program

heard in that channel. The PROGRAM switch must be ON for the control to function on that
channel. (The level controls work in conjunction with the PROGRAM TRIM (8) level control on
the rear panel.) For a higher program level, turn the control clockwise. For less program level
turn the control counter-clockwise. If the control is all the way up on a channel and the program

4