FieldServer Driver – Serial
FS-8700-31
Siemens TIWAY I
Description
The FieldServer Siemens TIWAY I driver, hereafter simply referred to as the TIWAY driver, can be used to emulate the host side of a Siemens Unilink Host Adaptor (UHA) using BDLC “Host Command Protocol”. The original Siemens UHA device was used to interface other host devices to a TIWAY I network as shown below:
The original Siemens UHA is really a protocol bridge in itself. It speaks “Host Command Protocol” on the host interface which may contain embedded TIWAY primitives (commands) and speaks Siemens TIWAY I protocol on its secondary interface. The FieldServer TIWAY I driver emulates the UHA’s host interface when used in the server mode, however the FieldServer does not speak Siemens TIWAY protocol and therefore cannot be used to connect to legacy TIWAY devices directly. The driver’s use is primarily as a server to allow legacy SCADA systems speaking “Host Command Protocol” containing TIWAY primitives to communicate with modern PLCs speaking Modbus or other industrial protocols. The accompanying FieldServer client driver in a configuration setup will typically be Modbus or some other industrial protocol. The TIWAY driver’s use as a client is limited to emulating a host to a UHA or for testing purposes.
The TIWAY driver operates in the Master Host Interface Unit ( MHIU ) mode and only supports a limited selected set of Host Adapter commands and TIWAY primitives which are listed under the Supported Host Adaptor Commands and Primitives section of this driver factsheet.
| Fieldserver Mode | Nodes | Comments |
| Client | 1 | Only 1 client node allowed |
| Server | 254 | Up to 254 secondary PLCs may be emulated |
Formal Driver Type
Serial
Client or Server
Connection Information
| Connection type: | RS-232C |
| Baud Rates: | 110; 300; 600; 1200; 2400; 4800; 9600; 19200; 28800; 38400; 57600; 115200 Baud |
| Data Bits: | 8 |
| Stop Bits: | 1,2 |
| Parity: | None |
| Multidrop Capability: | No |
Connection configurations
Connection Notes
Please refer to your SCADA system and FieldServer manual for connection pinouts before constructing a communications cable.
Communications functions
Supported functions at a glance:
Data Types Supported
| FieldServer Data Type | Description (or Device Data Type) |
| Raw – 16 bit word | Instruction Execution LadderVariable
Constant Word Input Word Output Word Force Timer or Counter Preset Timer or Counter Current Drum Count Preset |
| Digital Register – 16 bit word | Loop Status |
| Digital Input – 8 bit byte | Discrete Input |
| Digital Input – 8 bit packed byte | Discrete Input Packed |
| Digital Output – 8 bit byte | Discrete Output |
| Digital Output – 8 bit packed byte | Discrete Output Packed |
| Digital Register – 8 bit byte | Control RegisterDiscrete Force
Control Register Force |
| Digital Register – 8 bit packed byte | Control Register Packed |
| Raw – 8 bit byte | Drum Step PresetDrum Step Current |
| Analog Input / Output – 32 bit float | Loop GainLoop Reset
Loop Rate Loop High Alarm Loop Low Alarm Loop Process Variable Loop High Process Variable Loop Orange Deviation Loop Yellow Deviation Loop Sample Rate Loop Set Point Loop Output |
Read Operations supported
| FieldServer as a Client | FieldServer as a Server |
| Read Analog Status:Read Binary Status:
Read Raw Data: |
Provide Analog Status:Provide Binary Status:
Provide Raw Data: |
| Read Block PrimitiveRead Random Primitive | Respond to Read Block PrimitiveRespond to Read Random Primitive |
Write (control) Operations supported
| FieldServer as a Client | FieldServer as a Server |
| Write Analog Status:Write Binary Status:
Write Raw Data: |
Accept Analog Status:Accept Binary Status:
Accept Raw Data: |
| Write Block PrimitiveWrite Random Primitive
Fill Block Primitive |
Respond to Write Block PrimitiveRespond to Write Random Primitive
Respond to Fill Block Primitive |
Host Adaptor Protocol Commands Supported
| FieldServer Client / Server |
| 00 – Error Response |
| 01 – Send Network Data |
| 04 – Connect Secondaries |
| 05 – Disconnect Secondaries |
| 06 – Read Secondary Log |
| 11 – Configure HIU |
| 12 – Report HIU Configuration |
| 20 – Configure Adaptor |
| 21 – Report Adapter Configuration |
| 30 – Configure Network Manager |
| 31 – Report Network Manager Configuration |
| FE – Soft Reset |
| FF – Reset Adapter |
TIWAY 1 Primitives Supported
| FieldServer Client / Server |
| 00 – Exception |
| 02 – Status |
| 20 – Read Block |
| 21 – Read Random |
| 30 – Write Block |
| 31 – Write Random |
| 32 – Fill Block |
Unsupported Functions and Data Types
| Function | Reason |
| Programming messages | FieldServer is a data transfer device, and as such, programming messages are not required |
| Macro Commands 10,13-18,1C | Macro commands are for slower systems to auto-schedule primitives |
| HIU Performance Commands 19-1B | Performance parameters cannot be obtained since HIU to NIM interface does not exist on a FieldServer |
| Network Performance Commands 32-38 | The FieldServer has no interface to a TIWAY network. |
| All primitives not listed under supported list | Other primitives perform complex functions not pertaining to basic data transfer. May be implemented on request |
Functions Described
Unsupported Devices or Protocol Options
| Device / Protocol Option | Details |
| Non-Intelligent Terminal Protocol | Not suitable for this driver. BDLC protocol has much less overhead than NITP being an ASCII based protocol |
Revision History
| Date | Driver Version | Document Revision | Resp | Comment |
| 02/07/03 | 1.00a | 0 | DR | Created document |
| 04/24/03 | 1.00a | 1 | DR | Updated with new specifications after design review |
| 8/14/03 | 1.00a | 3 | JD | Releasing |