Datasheet

LTX-VCI Datasheet
LTX-VCI Iss1.05
RealTime Control Systems Ltd. Park House, Greenhill Crescent, Watford WD18 8PH. Tel [phone] Fax [phone] Page 4
Web: www.realtime-controls.co.uk , E-mail: [e-mail] LTX-VCI Datasheet Issue 1.05.01 12/07/2003 Doc No. 92101
1.3.2 BMS Interface
The VCI consists of four
VCI Proxy function blocks that manage data exchange between one
or more BMS interfaces and the A/C interface. Each proxy can be bound to a different LTX
controller in order to allow the control of up to 64 units. In the default configuration the main
proxy,
VCI Proxy[0] can be used to directly address up to 64 A/C units. The remaining three
proxies
VCI Proxy[1] to VCI Proxy[3] each address 16 consecutive units. The following are the
default address ranges of the units
Function Block Start Unit End Unit
VCI Proxy[0] 1 64
VCI Proxy[1] 17 32
VCI Proxy[2] 33 48
VCI Proxy[3] 49 64
In the simplest configuration a single LTX controller is bound to VCI Proxy[0] and can monitor
and control units in the range 1 to the maximum unit count for the LTX controller. Typically this
is to a limit of 16 units, but some new LTX controllers may be able to address up to 64 units.
If it is necessary to use more than one interface then each interface is bound to successive
VCI Proxies. For example a second LTX interface would be bound to VCI Proxy[1], this
performs a default mapping so that unit 1 in the second LTX corresponds to unit number 17 in
the VCI and unit 16 in the second LTX corresponds to unit number 32 in the VCI.
Each of the proxy function blocks has two configuration parameters
UCPTStartUnitOffset and
UCPTEndUnitOffset which can be used to map each proxy to any address range within the
range 1 to 64. If the configuration parameters are set to zero the function block will operate
with default address ranges outline above. These offset values can be used to map units into
the correct address range should a site addressing scheme not begin at 1.
1.3.3 Fault Code Mapping
Existing LTX controllers use an established fault reporting system that allows fault codes to be
translated and reported in various different BMS architectures. To retain backwards
compatibility the current version of the VCI translates manufacturers fault codes into the
established fault code format. In the BMS the LTX can be translated back into the native
manufacturers codes either manually or using suitable lookup mechanisms. Each Device
Interface Sheet provides the necessary translation between LTX and manufacturers fault
codes.