551 315 01

Service Channel (channel 0)   (USB Node)

Registers in Service channel:

RegNo	Identifier	Memory type	Read Out	Type
0	NumberOfSWNo	PROM Read only	-------	Record
1	DeviceID	PROM Read only	-------	Record
2	NeighbourNodeAddress	Ram Read only	Decimal	Byte
3	Reset	RAM Read Write	Decimal	Byte
4	PNETSerialNo	Special function	-------	Record
5
6
7	FreeRunTimer	RAM Read only	Decimal	LongInteger
8
9
10
11
12	NetParam	EEPROM RPW	-------	Record
13	WriteEnable	RAM Read Write	Binary	Boolean
14	Guid	PROM Read only	-------	String
15	ChError	RAM Read Write	-------	Record

RegNo 0: NumberOfSWNo

This constant holds the highest SWNo in the node, and a GUID for the entire device.

Record			(* Factory setting *)
	NumberOfSWNo:	Integer;	(* 47 *)
	DeviceGUID:	String[22];	(* ”57 0756500273 3" *)
	Reserved1:	Byte;
	HardwareGUID:	String[22];	(* "PD/601233-xx" *)
	KeyID:	Byte;
	BootloaderGUID:	String[22];	(* "PD/A30985-xx" *)
End;

RegNo 1: DeviceID

The purpose of this record is to be able to identify a connected device. The record includes registered manufacturer number, the type number of the device and a string identifying the manufacturer.

The record is of the following type:

Record			(* Factory setting *)
	DeviceNumber:	Word;	(* 3950 *)
	ProgramVersion:	Word;	(* xxx *)
	ManufacturerNo:	Word;	(* 1 *)
	Manufacturer:	String[20];	(* "PROCES-DATA DK" *)
End;

RegNo 2: NeighbourNodeAddress

This SWNo shows the nodeaddress of its neighbour. If the node is unable to obtain the NeighbourNodeAddress, this register will hold the value 254 and an actual data error will be set in the response.

NeighbourNodeAddress:

Byte;

RegNo 3: Reset

Reset:

Byte;

By writing 255 to the Reset variable, the device will perform a reset, and ExternalReset in ChError will be set TRUE. Any other value than 255 can cause random behaviour.

RegNo 4: PNETSerialNo

This variable is a record of the following type:

Record			(* Factory setting *)
	PNETNo:	Byte;	(* 0 *)
	NoOfMaster	Byte;	(* 0 *)
	SerialNo:	String[20];	(* "xxxxxxxxPD" *)
End;

The serial number is used for service purposes and acts as a 'key' for setting the P-NET address and number of masters for the P-NET node.

A special function is included for identifying a device connected to a network containing many other devices, having the same or unknown node addresses, and to enable a change of the node address and number of masters via the P-NET.

Setting a new node address and number of masters via P-NET, is performed by writing the required node address and number of masters, together with the serial number of the device in question, into the PNETSerialNo at node address 126 (calling all devices). All nodes on the P-NET will receive the message, but only the node in the device with the transmitted serial number will store the node address and the number of masters.

An attempt to write data to node address 126 will give no reply. Consequently the calling master must disable the generation of a transmission error when addressing this node.

In the device, the SerialNo = "XXXXXXXXPD", is set by PROCES-DATA, and cannot be changed. The eight “X”es indicate the serial number, and PD is the initials of PROCES-DATA.

RegNo 7: FreeRunTimer

FreeRunTimer:

LongInteger;

FreeRunTimer is a timer to which internal events are synchronized. The timer is of type LongInteger in 1/256 Second.

RegNo 12: NetParam

This variable is a record having the following structure:

Record			(* Factory setting *)
	Baudrate:	LongInteger;	(* 76800 *)
	Errorcheck:	Boolean;	(* FALSE *)
	NoOfMasters:	Byte;	(* 0 *)
	Retries	Byte;	(* 0 *)
End;

This variable holds the net parameters Baudrate, ErrorCheck and NoOfMasters for the port used to access the variable. For example, if the variable is accessed from port 1, the net parameters for port 1 are accessed. The variable can’t be accessed from Process-Pascal.

The variable is stored in memory type EEPROM RPW, meaning it can only be changed if WriteEnable is True.

Baudrate

Baudrate holds the bit rate for the port from which the variable is accessed. Which values are legal depends on the type of the port.

ErrorCheck

ErrorCheck holds the errorcheck method used for the port from which the variable is accessed. False means “Default (1 byte) errorcheck”, and True means “Extended (2 byte) errorcheck”.

NoOfMasters

The value of NoOfMasters can be from 0 to 32 but no requests will be sent on P-NET while NoOfMasters = 0.

Retries

This register defines the maximum number of retries made in the event of a transmission error, before the error is reported. The defined maximum number of retries is for each block in a LONG LOAD / STORE. Therefore, the value of Retries should be very low.

RegNo 13: WriteEnable

WriteEnable:

Boolean;

Write protected variables can only be changed when WriteEnable is TRUE. After reset, WriteEnable is set to FALSE.

RegNo 14: GUID

GUID:

String[22];

(* "PD/551315-01" *)

Each channel type is identified by means of a unique GUID. The value of GUID for the Service channel is: PD/551315-01.

RegNo 15: ChError

Record
	His:	Bit16;
	Act:	Bit16;
End;

There are two sets of error bits, actual and historical. The actual error bits reflect the current situation and will automatically follow any change.

The historical error bits reflect past situations and have the job of holding sporadic errors. The historical error bits are set together with the corresponding actual bits. They remain set after a read, so each individual bit must be cleared by setting it to FALSE. Only the bits where the corresponding actual bit is FALSE can be cleared.

The “His data error” bit in the P-NET response is set if any historical bit is TRUE.

The “Act data error” bit in the P-NET response reflects the validity of the data in the response. Overload, electrical error or an error in other registers involved in calculating the result gives “Act data error”.

15	7	0
			0: Program_storage_fault
			1: RAM_storage_fault
			2: InternalReset
			3: ExternalReset
			4: ModuleError
			5: Not Used
			6: Not Used
			7: Not Used
			8:EEPROM_Error_In_PNETSerialNo
			9: EEPROM_Error_In_NetParam
			10: PNET_Sync_Error
			11: Not Used
			12: Not Used
			13: Not Used
			14: Not Used
			15: Not Used

Bit 0	Program_storage_fault is set TRUE if the self-test finds an error in the program memory.
Bit 1	RAM_storage_fault is set TRUE if the self-test finds an error in the data memory (RAM).
Bit 2	InternalReset is set TRUE if a reset is caused by a power failure, or if the power has been disconnected (only a His error).
Bit 3	ExternalReset is set TRUE if a reset is caused by writing 255 to Reset, via P‑NET (only a His error).
Bit 4	ModuleError is set if a module error occurs.
Bit 8	EEPROM_Error_In_PNETSerialNo
Bit 9	EEPROM_Error_In_NetParam
Bit 10	PNET_Sync_Error is generated when a P-NET synchronization error occurs. This is typically a result of a different NoOfMasters set in devices connected to the same link. Refer to the P-NET standard for further information. The error is cleared when synchronization is regained.