Installation guide

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3015-4570

Revision 1.1

8/6/03

Installation Guide

Bacharach HGM300 to Johnson Metasys N2

Communications Adapter

Electrically Isolated N2 Port Version

Introduction

The Bacharach HGM300 to Johnson Metasys N2 Communcations Adapter enables an

HGM300 Refrigerant Monitor to communicate with a Metasys building management

system. Zone PPM readings, flow status, refrigerant selections, and HGM internal health

may be viewed on Metasys operator stations. In addition, each HGM zone supports three

levels of alarming (Leak, Spill, Evacuate) through Metasys and each alarm threshold can

be set through Metasys.

The N2 Communications Adapter can be used in conjunction with the RDM800 remote

display if desired. Wiring details and operation limitations when using the RDM800 will

be discussed below.

Caution

The adapter is powered from the 120V Auxiliary Power connection on the HGM main

board. When the HGM is powered up, 120V is present on the lower left corner of the

adapter within the area shown on the board silkscreen. Keep fingers away from this area

when HGM is powered!!

Adapter Installation Inside HGM300

The communications adapter board will normally be installed in the HGM300 at the

factory. It can, however, be field installed by following the instructions below.

The following installation materials are needed for field installation of the adapter:

(5) 6-32 x ¼” screws (standard finish)

(5) 6-32 x ½” threaded standoffs

(5) 6-32 x ¼” decorative black anodized screws (standard finish OK, black looks nicer)

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Summary of content (10 pages)

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3015-4570 Revision 1.1 8/6/03 Installation Guide Bacharach HGM300 to Johnson Metasys N2 Communications Adapter Electrically Isolated N2 Port Version Introduction The Bacharach HGM300 to Johnson Metasys N2 Communcations Adapter enables an HGM300 Refrigerant Monitor to communicate with a Metasys building management system. Zone PPM readings, flow status, refrigerant selections, and HGM internal health may be viewed on Metasys operator stations.
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The adapter board mounts on the rear of the HGM300 door. Position the adapter board so as not to interfere with the HGM internal components when the door is shut. Mark (Figure 1) and drill the board’s four corner holes and center hole in the door. Install the five standoffs on the rear side of the door using the five black decorative screws on the front side of the door. Position the adapter board over the standoffs mounted on the HGM door.
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If an RDM800 remote display is NOT used with the adapter, refer to Figure 2 for wiring details. In this case, all wiring between the HGM300 main board and adapter is contained within the HGM300 and the only external cable is the N2 communications cable.
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If an RDM800 remote display IS to be used with the adapter, refer to Figure 3 for wiring details. Note that when the RDM800 is used, TWO RS-485 cables must be run between the HGM300 and RDM800, so plan accordingly. In either case, be sure to set the HGM300’s internal “Terminator” slide switch next to the RS-485 terminal block to the “In” position.
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Field Hookup of N2 Communications The “BAS BUS” (N2) RS-485 communications port on the adapter is electrically isolated from the HGM300 and from earth ground. This prevents problems with potential differences in “ground” between physically separate locations. Connect the N2 ‘+’ wire to the BAS BUS N+ terminal block screw. Connect the N2 ‘-‘ wire to the BAS BUS N- terminal block screw. Connect the N2 REF wire to the BAS BUS REF terminal block screw. Shield connection practices vary.
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Setting Metasys N2 Address On Communication Adapter Switches 1-8 on the adapter’s ‘B’ dipswitch are used to set the Metasys N2 node address. Possible addresses are 1-255. Use the following technique to set switches B1-B8: Divide the desired N2 address by 16.
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Configuring the HGM300 with RDM800 or Laptop PC The only HGM parameters that are changeable through Metasys are the alarm thresholds. Configuring the HGM for refrigerant type and length of tubing for each zone (zero length to disable a zone) must be done with the RDM800 remote display or a laptop PC. Refer to the appropriate Bacharach instructions for configuring these items.
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There are several ADI points which can provide useful information such as type of refrigerant programmed for each zone, number of zones actually installed in the HGM, the number of zones in alarm, HGM operating mode, etc. Alarm Acknowledge Options Two alarm acknowledge options are supported—Auto Acknowledge and Network Acknowledge. In the Auto Acknowledge mode, the HGM will clear its alarm outputs the next time the alarmed zone is sampled and its PPM has dropped below the alarm thresholds.
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Communications LED Indicators See Figure 4 for the locations of the communications LED indicators. The communications adapter board has four LED communications status indicators numbered 1-4.