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FieldServer Driver - Serial
FS-8700-80
McQuay Microtech Open Protocol
Description
This is an active client protocol. The driver is capable of acting as a master or slave. As a master, the Fieldserver polls to read or write the McQuay device. As a slave the FieldServer accepts read/write request and responds appropriately.
The vendor equipment is limited to a maximum of 9600 baud. Given that each message packet can only transfer one byte of data and that some data of interest is multi-byte, users of this protocol should expect low data transfer rates.
The driver can poll for one or more specific data fields of interest at a rate set by the user or all available data can be read at a rate determined by the driver.
Scaling:
The driver scales data read/written by a factor identified in the driver manual. The values stored in many data fields are stored to allow for real numbers with fractional components to be stored as whole numbers. For example: Oil Pressure - Feed (stored at memory location 0446-0447) is stored as a number between 0 and 4500. The driver reports the value by storing a real number in the range 0.0-450.0 in a data array.
Additional scaling may be applied by the user by specifying scaling factors in the FieldServer configuration.
Functions:
| Function | Description |
| Read | Reads a single data field. |
| Write | Writes a single data field to the McQuay device. Only some data fields in the McQuay device may be written to. |
Formal Driver Type
- Serial
- Client or Server
Compatibility Matrix
| FieldServer Model | Compatible with this driver |
| FS-B2010 | Yes, No |
| FS-B2011 | Yes, No |
| FS-B40 | Yes |
Connection Information
| Connection type: | RJ45 Pigtail for RS-232/RS-485 |
| Baud Rates: | 110- 9600. (Vendor limited) |
| Data Bits: | 7 |
| Stop Bits: | 1 |
| Parity: | Even |
| Multidrop Capability: | Yes |
Connection configurations
The FieldServer is connected to the McQuay device as shown below.
Configure the McQuay device according to manufacturer's instructions.
Communications functions
Supported functions at a glance:
Data Types Supported
| FieldServer Data Type | Description (or Device Data Type) |
| 200CFC - 200 Series Centrifugal Chiller | Data fields of interest my be specified using the data field name or by specifying the address / memory location |
| 100CFC - 100 Series Centrifugal Chiller | |
| 001ASC - Air Screw Chiller | |
| 000SCU - Self Contained Unit | |
| 0050RPC - Reciprocating Chiller | |
| Other devices | Any other device which supports McQuay's Open Protocol(tm) Data Communications Information Packet Version 1.4 April, 1996 can be read or written using this driver. However, when read or writing these 'other' devices, the data fields of interest are specified using the 'address / memory location' specified as a hexadecimal number (obtained for the product specification.) At a customer's request the driver can be updated to allow the fields to be specified by their field names. |
Unsupported Functions and Data Types
As a slave the driver can have a maximum of one master connected per port.
The following important points and limitations should be noted.
- Arising from a feature of the McQuay open protocol is the peculiarity, that when a multi-byte value is written to a McQuay device, the write is done one byte at a time (one byte of data can be transferred per poll/response message pair.) allowing for the possibility (at least for a short period) that the multi byte value is only partially correct until all the messages have been completed.
- The vendor equipment is limited to a maximum of 9600 baud. Given that each message packet can only transfer one byte of data and that some data of interest is multi-byte, users of this protocol should expect low data transfer rates.
- Port expansion is not supported for this driver.
A document identified as Ed15050 MicroTech Network Operations contains important and useful information regarding the connection requirements of 3rd party equipment (like the FieldServer) to a Microtech network. The document also defines a number of limitations for such connections.
PC Connection
The following quotations from this document outline some of this information.The PC connection to a MicroTech controller is through an available port A that is configured as TTY. It is best to connect the PC to a level-1 controller because data transmission is the fastest. However, a PC can be connected to any level-2 controller that does not have level-3 controllers connected to it or to any MicroTech level-3 controller. Regardless of where you connect the PC, you have access to the entire network.
You can connect two or more PCs to the network, but only one PC can be connected to a particular controller. The PC that you use most often should be connected to the level-1 controller for best performance. For example, you may have one PC that you use on site and another PC that you use off site. In this situation, you may want to connect the on-site PC to the level-1 controller and the modem for the off-site PC to a level-2 or level-3 controller.
If a PC is connected to a level-2 controller, a level 1 controller must poll that level-2 controller connected to the PC so that the PC has access to the entire network. Defining a level-2 controller in the level-1 controller slave list causes the level-1 controller to poll the level-2 controller.
Port Configuration: The communications port that the PC is connected to must be configured as a TTY port. As shown in Error! Reference source not found., the default port configuration for most MicroTech controllers sets port A as TTY. The port configuration is a software setting.
A separate software setting defines the communications rate of each port. In most controllers, the default rate is 9600 bps.
TTY: A TTY port is used to connect a PC for monitoring purposes. It uses the RS232C interface standard and the Data Terminal Communications protocol.
The following quote from "MicroTech(r) Data Terminal Communication Packets, Open Protocol(tm) Data Communications Information Packet Version 1.4" is an important limitation of the protocol.
Data terminal communications may be sent via RS-232C or RS-485. Regardless of the electrical standard used for communications, this protocol is a single ended type (i.e., communications to one MicroTech controller maximum).- Each MicroTech controller is shipped from the factory with a unique job site password. The password is provided by the McQuay International representative at the time of startup.
- The driver does not validate passwords when configured as a server. This means that requests to read or write data will succeed even if the password supplied with the request is incorrect.
Equipment Type: 200CFC 200 Series Centrifugal Chiller
Additional information may be obtained from McQuay International. Request the following document.
Series 200 Centrifugal Chiller
Data Communications Packet for Open Protocol(tm)
Cent2_22.doc
| Array Location | Read/ Write/ Both | Field Name | Number of Bytes | Base Address | Device Scaling Method |
| 1 | r | Model | 3 | 0x0A08 | 1 |
| 4 | r | Refrigerant | 1 | 0x0A0B | 1 |
| 5 | r | Units of Measure | 1 | 0x0A0C | 1 |
| 6 | r | Software Version | 2 | 0x0A0D | 1 |
| 8 | r | Software Revision | 1 | 0x0A0F | 1 |
| 11 | r | Chiller Unit Temperature Type | 1 | 0x084B | 1 |
| 12 | r | Communication Status | 1 | 0x040C | 1 |
| 13 | r | Compressor Lift Pressure | 2 | 0x046A | 2 |
| 15 | r | Compressor Motor Current | 2 | 0x044C | 1 |
| 17 | r | Compressor Motor Current Percent | 1 | 0x044A | 1 |
| 18 | r | Compressor Number of Starts | 2 | 0x085F | 1 |
| 20 | r | Compressor Operating Hours | 2 | 0x0851 | 1 |
| 22 | r | Compressor Suction Temperature | 2 | 0x043A | 3 |
| 24 | r | Compressor Superheat - Discharge | 2 | 0x046E | 2 |
| 26 | r | Compressor Superheat -Suction | 2 | 0x046C | 2 |
| 28 | r | Condenser Approach Temperature | 2 | 0x0484 | 2 |
| 30 | r | Condenser Heat Recovery Unit Present | 1 | 0x083F | 1 |
| 31 | r | Condenser Heat Recovery Temperature - Delta | 2 | 0x048A | 2 |
| 33 | r | Condenser Heat Recovery Water Temp. - Entering | 2 | 0x0454 | 3 |
| 35 | r | Condenser Heat Recovery Water Temp. - Leaving | 2 | 0x0456 | 3 |
| 37 | r | Condenser Pump Status | 1 | 0x0425 | 1 |
| 38 | r | Condenser Pump # 1 Operating Hours | 2 | 0x085A | 1 |
| 40 | r | Condenser Pump # 2 Operating Hours | 2 | 0x085D | 1 |
| 42 | r | Condenser Refrigerant Pressure | 2 | 0x0440 | 2 |
| 44 | r | Condenser Refrigerant Temperature | 2 | 0x0466 | 3 |
| 46 | r | Condenser Subcooling Temperature | 2 | 0x0480 | 2 |
| 48 | r | Condenser Water Flow Rate | 2 | 0x0452 | 1 |
| 50 | r | Condenser Water Flow Status | 1 | 0x045F | 1 |
| 51 | r | Condenser Water Rate Sensor | 1 | 0x083D | 1 |
| 52 | r | Condenser Water Temperature - Delta | 2 | 0x0488 | 2 |
| 54 | r | Condenser Water Temperature - Entering | 2 | 0x0436 | 3 |
| 56 | r | Condenser Water Temperature - Leaving | 2 | 0x0434 | 3 |
| 58 | r | Cooling Tower Control | 1 | 0x0926 | 1 |
| 59 | r | Cooling Tower Stage | 1 | 0x049A | 1 |
| 60 | r | Cooling Tower Valve Position | 1 | 0x049B | 1 |
| 61 | r | Discharge Refrigerant Temperature | 2 | 0x043E | 3 |
| 63 | r | Evaporator Approach Temperature | 2 | 0x0482 | 2 |
| 65 | r | Evaporator Pump Status | 1 | 0x0423 | 1 |
| 66 | r | Evaporator Pump #1 Operating Hours | 2 | 0x0854 | 1 |
| 68 | r | Evaporator Pump #2Operating Hours | 2 | 0x0857 | 1 |
| 70 | r | Evaporator Refrigerant Pressure | 2 | 0x0438 | 2 |
| 72 | r | Evaporator Refrigerant Temperature | 2 | 0x0464 | 3 |
| 74 | r | Evaporator Water Flow Rate | 2 | 0x0450 | 1 |
| 76 | r | Evaporator Water Flow Status | 1 | 0x045E | 1 |
| 77 | r | Evaporator Water Rate Sensor | 1 | 0x083C | 1 |
| 78 | r | Evaporator Water Temperature - Delta | 2 | 0x0486 | 2 |
| 80 | r | Evaporator Water Temperature - Entering | 2 | 0x0432 | 3 |
| 82 | r | Evaporator Water Temperature - Leaving | 2 | 0x0430 | 3 |
| 84 | r | Fault - Current Active | 1 | 0x1C00 | 1 |
| 85 | r | Last Start Hour | 1 | 0x0861 | 1 |
| 86 | r | Last Start Minute | 1 | 0x0862 | 1 |
| 87 | r | Last Start Month | 1 | 0x0863 | 1 |
| 88 | r | Last Start Date | 1 | 0x0864 | 1 |
| 89 | r | Last Start Year | 1 | 0x0865 | 1 |
| 90 | r | Last Stop Hour | 1 | 0x0866 | 1 |
| 91 | r | Last Stop Minute | 1 | 0x0867 | 1 |
| 92 | r | Last Stop Month | 1 | 0x0868 | 1 |
| 93 | r | Last Stop Date | 1 | 0x0869 | 1 |
| 94 | r | Last Stop Year | 1 | 0x086A | 1 |
| 95 | r | Liquid Line Refrigerant Temperature | 2 | 0x043C | 3 |
| 97 | r | Oil Pressure - Feed | 2 | 0x0446 | 2 |
| 99 | r | Oil Pressure - Net | 2 | 0x0468 | 2 |
| 101 | r | Oil Pressure - Vent | 2 | 0x04AC | 2 |
| 103 | r | Oil Temperature - Feed | 2 | 0x0442 | 3 |
| 105 | r | Oil Temperature - Sump | 2 | 0x0444 | 3 |
| 107 | r | Outdoor Air Temperature - Network | 1 | 0x0474 | 2 |
| 108 | r | Refrigerant Detection Sensor | 1 | 0x083E | 1 |
| 109 | r | Refrigerant Leak Detection Limit | 1 | 0x044B | 1 |
| 110 | r | Unit Status | 1 | 0x0420 | 1 |
| 111 | b | Capacity Limit Percent | 1 | 0x0475 | 1 |
| 112 | b | Clear Current Fault | 1 | 0x041E | 1 |
| 113 | b | Chiller Operation Mode | 1 | 0x0477 | 1 |
| 114 | b | Chilled Water Temperature Setpoint | 1 | 0x0476 | 1 |
| 115 | b | Communications Signal | 1 | 0x047D | 4 |
| 116 | b | Outdoor Air Temperature - BAS | 1 | 0x0473 | 5 |
| 117 | b | Master/Slave Setpoint | 1 | 0x093C | 1 |
| 118 | b | Lead/Lag Mode Setpoint | 1 | 0x093D | 1 |
| 119 | b | Enable Lag Setpoint | 1 | 0x093E | 1 |
| 120 | b | Disable Lag Setpoint | 1 | 0x093F | 1 |
| 121 | b | Lag Standby Setpoint | 1 | 0x0942 | 1 |
| 122 | b | Lead/Lag Switch Setpoint (Day) | 1 | 0x0948 | 1 |
| 123 | b | Lead/Lag Switch Setpoint (Hour) | 1 | 0x0949 | 1 |
| 124 | r | Lead/Lag Status | 1 | 0x0401 | 1 |
| 125 | r | Lead Unit | 1 | 0x0402 | 1 |
| 126 | r | Lead Unit Status | 1 | 0x0403 | 1 |
| 127 | r | Lag Unit Status | 1 | 0x0404 | 1 |
| 128 | r | Lead Motor Current | 1 | 0x0405 | 1 |
| 129 | r | Lag Motor Current | 1 | 0x0406 | 1 |
| 130 | r | Lead Status | 1 | 0x0407 | 1 |
| 131 | r | Lag Status | 1 | 0x0408 | 1 |