FieldServer FS-8700-66 User Manual

-

Driver Version:

1.02

A Sierra Monitor Company

Driver Manual

(Supplement to the FieldServer Instruction Manual)

FS-8700-66 GE SNP

APPLICABILITY & EFFECTIVITY

Effective for all systems manufactured after May 1, 2001

Document Revision: 9

FS-8700-66_GE-SNP Manual Table of Contents

TABLE OF CONTENTS

1.

GE_SNP Description ...................................................................................................... 3

2.

Driver Scope of Supply .................................................................................................. 4

2.1.

Supplied by FieldServer Technologies for this driver.................................................. 4

3.

Hardware Connections .................................................................................................. 5

4.

Configuring the FieldServer as a GE_SNP Client ........................................................ 8

4.1.

Data Arrays/Descriptors............................................................................................. 8

4.2.

Client Side Connection Descriptors............................................................................ 9

4.3.

Client Side Node Descriptors ....................................................................................10

4.4.

Client Side Map Descriptors......................................................................................10

4.4.1. FieldServer Related Map Descriptor Parameters...................................................10

4.4.2. Driver Related Map Descriptor Parameters............................................................11

4.4.3. Timing Parameters ................................................................................................11

4.4.4. Map Descriptor Example 1 – Simple Read.............................................................12

4.4.5. Map Descriptor Example 2 – Simple Write.............................................................12

4.4.6. Map Descriptor Example 3 – Handling Bits............................................................13

5.

Configuring the FieldServer as a GE_SNP Server ......................................................14

5.1.

Server Side Connection Descriptors .........................................................................14

5.2.

Server Side Node Descriptors...................................................................................15

5.3.

Server Side Map Descriptors ....................................................................................16

5.3.1. FieldServer Specific Map Descriptor Parameters...................................................16

5.3.2. Driver Specific Map Descriptor Parameters ...........................................................16

5.3.3. Timing Parameters ................................................................................................17

5.3.4. Map Descriptor Example........................................................................................18

Appendix A. Troubleshooting Tips....................................................................................19

Appendix B. Error Messages .............................................................................................20

Appendix B.1. Driver Stats ..................................................................................................22

Appendix C. Advanced Topics...........................................................................................25

Appendix C.1. SNP Node Names .......................................................................................25

Appendix C.2. Scaling.........................................................................................................26

Appendix C.3. Server Response NAK, Major and Minor Error Codes .................................26

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 3 of 29FS-8700-66_GE-SNP Manual Page 3 of 29

1. GE_SNP Description

The GE-SNP Serial driver allows the FieldServer to transfer data to and from devices over
either RS-232 or RS-485 using GE-SNP Serial protocol. The FieldServer can emulate either a
Server or Client.

The FieldServer provides functions to read and write PLC memory and change the privilege
level. Standard SNP mailbox messages are used. The driver does not support Datagram
messages and cannot parse them. These messages are defined by the SNP protocol to allow
multiple data types to be packed into one message. They are not commonly used by the HMI
and 3rd party applications and are inconsistent with the FieldServer’s Write Through and Port
Expander capabilities.

The driver can expose communications statistics in a Data Array so that downstream devices
can monitor them.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 4 of 29FS-8700-66_GE-SNP Manual Page 4 of 29

2. Driver Scope of Supply

2.1. Supplied by FieldServer Technologies for this driver

FieldServer Technologies
PART #

Description

FS-8915-10 UTP cable (7 foot) for RS-232 use
FS-8917-03 RJ45 to DB9M connector adapter
FS-8700-66 Driver Manual.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 5 of 29FS-8700-66_GE-SNP Manual Page 5 of 29

04

3. Hardware Connections

The FieldServer is connected to the GE PLC in one of two ways.

Almost every GE PLC has a RS-232 and RS-485 port. Possible cable configurations are
illustrated below.

A converter is required to connect between RS-232 and RS-485. An example of connection
configurations for the Model480TLED connector is depicted overleaf. Any equivalent connector
can be used.

RS-485 port

Cable 1

RS-485 port

15 pin female

FieldServer GE-PLC

C

a

b

l

e

4

RS-232 port

Pin 1 at bottom

Cable 1

FieldServer

+

Tx

-

+

Rx

-

Gnd

RS-232 port

3

e

l

b

a

C

Cable 2

GE

10

+

Tx

-

11

12

+

Rx

-

13

7

Gnd

RJ11

Cable 2

FieldServer

Tx

Rx

Gnd

-

GE

5

Rx

Tx

2

3

Gnd

4

1

CTS

*

6

RTS

CONNECTION DIAGRAM

BASE NAME:
FILE NAME:

GE SNP

DATE: 2/2/
BY: MF

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 6 of 29FS-8700-66_GE-SNP Manual Page 6 of 29

Remote Serial

Device – 4 wire

TDA(-)
TDB (+)

- (A)

GND

RDB(+)
RDA(-)

GND

FS-8917-01

From FieldServer

ECHO

4800

9600

19.2K

38.4K

4W/2W

4W/2W

TERM.

TB1

TB2

JP1

SD

RTS

RS- 232 TO RS-422/485

2

3

OPTICALLY ISOLATED

2

RS-232

3

CONVERTER

Recceive

4

5

7

7

B&B

Transmit

electronics

MODEL 485OTLED

J2

DB25F

21787

91035

O
N

1 2 3 4 5 6 7 8

SR-422/485

422/ 485 GND

TDA(-)

TDB(+)

RDA(-)

RDB(+)

+12V

R-232

GND

Converter for Cable 3: From RS-232 on FieldServer to RS-485 on device.

Remote Serial

Device – 2 wire

+ (B)

RS-232 Device

Rx

2

Tx

3

RTS

5

GND

J2

7

Note: Pins 4&5 and pins 6,8&20 are
bridged internally to allow for RS-232
devices that need hardware control.

RTS

GND

Rx

Tx

DB25F

RS-232 TO RS-422/485
OPTICALLY ISOLATED

2

3

RS-232

CONVERTER

4

7

B&B

MODEL 485OTLED

Recceive

Transmit

electronics

91035

4800

9600

O
N

1 2 3 4 5 6 7 8

SR-422/485

19.2K

38.4K

TDA(-)

TDB(+)

RDA(-)

RDB(+)

422/485

+12V

R-232

GND

GND

ECHO

4W/2W

4W/2W

TERM.

JP1

TB1

TB2

Converter for Cable 4: From RS-485 on FieldServer to RS-323 on device.

CONNECTION DIAGRAM

RS-485 to RS-232 using

Model4850 TLED connector.

SD

RTS

GE SNP

FieldServer

R1 or R2

+ (B)

- (A)

GND

BASE NAME:

FILE NAME:

FS-8700-66-1

DATE: 2/16/08

BY: MC

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 7 of 29FS-8700-66_GE-SNP Manual Page 7 of 29

RJ45

g

b

w

b

y
e

r

l

l

h

u

a

e

l

i

l

e

c

e

t

o

e

k

n

w

5

2

3

6

7

5 3 2 7 6

Horner

232

to

422

CPU or 2ndary port

PLC

Pri or 2ndary port

Horner

232

to

422

2

5

3

w

n

k

e
t

o

e

e

c

i

l

l

e

u

a

h

r

l

l

e

g

w

b

y

b

9 pin

9 pin

9 pin

9 pin

15 pin

15 pin

Ethernet cable segment

RJ45

g

b

w

b

y
e

r

l

l

h

a

u

e

l

i

l

e

c

e

t

o

e

k

n

w

5 3 2

null modem

Com1

PC

9 pin

9 pin

25 pin

GE LOGICMASTER
PC Software to PLC

9 pin

RJ45

RJ45

P1-P8

Typical

FieldServer

Cable

CONNECTION DIAGRAM

GE SNP

BASE NAME:
FILE NAME:

(408)-262-2299

DATE: 2/2/04
BY: MF

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 8 of 29FS-8700-66_GE-SNP Manual Page 8 of 29

4. Configuring the FieldServer as a GE_SNP Client

For a detailed discussion on FieldServer configuration, please refer to the FieldServer
Configuration Manual. The information that follows describes how to expand upon the factory
defaults provided in the configuration files included with the FieldServer (See “.csv” sample files
provided with the FieldServer).

This section documents and describes the parameters necessary for configuring the FieldServer
to communicate with a GE_SNP Server.

4.1. Data Arrays/Descriptors

The configuration file tells the FieldServer about its interfaces, and the routing of data
required. In order to enable the FieldServer for GE_SNP communications, the driver
independent FieldServer buffers need to be declared in the “Data Arrays” section, the
destination device addresses need to be declared in the “Client Side Nodes” section, and
the data required from the Servers needs to be mapped in the “Client Side Map Descriptors”
section. Details on how to do this can be found below.

Note that in the tables, * indicates an optional parameter, with the bold legal value being the
default.

Section Title

Data_Arrays

Column Title Function Legal Values

Data_Array_Name Provide name for Data Array

Data_Array_Format

Provide data format. Each Data Array
can only take on one format.

Number of Data Objects. Must be

Data_Array_Length

larger than the data storage area
required by the Map Descriptors for
the data being placed in this array.

Example

// Data Arrays
Data_Arrays
Data_Array_Name, Data_Format, Data_Array_Length
DA_AI_01, UInt16, 200
DA_AO_01, UInt16, 200
DA_DI_01, Bit, 200
DA_DO_01, Bit, 200

Up to 15 alphanumeric
characters
Float, Bit, UInt16, SInt16,
Packed_Bit, Byte,
Packed_Byte,
Swapped_Byte

1-10,000

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Page 9 of 29FS-8700-66_GE-SNP Manual Page 9 of 29

4.2. Client Side Connection Descriptors

Section Title

Connections

Column Title Function Legal Values

Port

Protocol Specify protocol used SNP

Baud* Specify baud rate

Parity* Specify parity
Data_Bits* Specify data bits
Stop_Bits* Specify stop bits
Handshaking* Hnadshaking is not supported
Poll _Delay* Time between internal polls

Timeout

Example

// Client Side Connections

Connections
Port, Protocol, Baud, Parity, Handshaking, Poll_Delay
P1, SNP, 19200, Odd, None, 0.100s

GE Port Defaults

Baud 19,200 19,200
Data Bits 8 8
Parity Odd Odd
Stop Bits 1 1
Max Link Idle Time 10 Secs 5 Secs

GE Port Capabilities

Baud 300, 600, 1200, 2400, 4800, 9600, 19200
Data Bits 8
Parity Odd, Even, None
Stop Bits 1, 2
Max Link Idle Time 1 to 60 Secs

Specify which port the device is
connected to the FieldServer

P1-P8, R1-R21

110 – 19200, standard baud rates
only (Vendor limitation), 19200
Even, Odd, None, Mark, Space
7, 8

1
None

0-32000 seconds, 1 second
The timeout specified for the connection is used as the data link layer
timeout. It is also used as the timeout for each Map Descriptor if a timeout
is not explicitly defined for a Map Descriptor.

Series 90-30 PLC’s Series 90-70 PLC’s

1

Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction

manual for details of the ports available on specific hardware.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

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Page 10 of 29FS-8700-66_GE-SNP Manual Page 10 of 29

4.3. Client Side Node Descriptors

Section Title

Nodes

Column Title Function Legal Values

Provide name for Node. The driver
uses the Node name to establish a
connection with the Server if the
Node_ID is non-zero.

Node_Name

If the Node_ID is zero then the driver
ignores the Node name when logging
onto the PLC and logs on using a
Null name. Thus by setting the
Node_ID to zero you can allow the
driver to log onto a Node whose
name is not known.
The parameter is used to control how

Node_ID

the driver logs onto the PLC. Read
the notes above (Node_Name)

Protocol Specify protocol used SNP

Port

Specify which port the device is
connected to the FieldServer

Example

// Client Side Nodes
Nodes
Node_Name, Node_ID, Protocol, Port
PLC 1, 1, SNP, P8

Up to 32 alphanumeric
characters

0,1

P1-P8, R1-R22

4.4. Client Side Map Descriptors

4.4.1. FieldServer Related Map Descriptor Parameters

Column Title Function Legal Values

Map_Descriptor_Name Name of this Map Descriptor

Name of Data Array where

Data_Array_Name

data is to be stored in the
FieldServer

Data_Array_Offset Starting location in Data Array

Function

2

Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction

manual for details of the ports available on specific hardware.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Function of Client Map
Descriptor

Up to 32 alphanumeric
characters
One of the Data Array names
from “Data Array” section
above
0 to maximum specified in
“Data Array” section above

RDBC, WRBC, WRBX

Page 11 of 29FS-8700-66_GE-SNP Manual Page 11 of 29

4.4.2. Driver Related Map Descriptor Parameters

Column

Title

Function Legal Values

Node_Name Name of Node to fetch data from

Data_Type Data type

Length

Length of Map Descriptor. Ensure that the
length does not exceed the table in the PLC
Starting address of read block / write block. The

Address

1st element of each Data type Table is referred
to as address one.
Use to override the default format for obtaining
data. Bit tables are by default read by reading
whole bytes at a time (If the Length is 10 then
10 bytes of data are read and placed in 10 Data

Format*

Array locations)

If you wish to read bits instead then use this
parameter. (If the Length is 10 then 10 bits are
read and each bit is stored in its own location.)
This parameter is only specified when you
create a write Map Descriptor to change the

GE_Func*

privilege level.

If it is not specified the driver assumes the
default (RW – Read/Write).

One of the Node
names specified in
“Client Node
Descriptor” above
Discrete Inputs (%I)
Discrete Outputs (%Q)
Discrete Temporaries
(%T)
Discrete Internals
(%M)
Genius Global Data
(%G)
Analog Inputs (%AI)
Analog Outputs
(%AQ)
Registers (%R)
%SA Discrete
%SB Discrete
%SC Discrete
%S Discrete (%S)

1-1000

1 , 2 , 3
Positive whole
numbers

Bit, Byte

The format for %AI,
%AQ and %R cannot
be changed.

CPL, RW

4.4.3. Timing Parameters

Column Title Function Legal Values

Scan_Interval Rate at which data is polled ≥0.1s

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

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Data_Type

Use the % symbol

as you would if you

were programming a

Read will be

performed every

2.0s.

GE PLC.

Data_Type

Write to the %AQ

(Analog Output)

table in the PLC.

Scan_Interval,

element). The PLC is polled every 2

st

Length

Address

The address and length

specify the first element

and the number of

elements that must be

read from the PLC’s

data tables. GE PLC’s

reference data tables

starting at element 1.

Unless otherwise

specified, the driver

reads bytes and words.

This Map Descriptor

reads bytes of data

covering %I1 to %I79

Node_Name

The Node must

have been

defined in the

Nodes section of

the CSV file.

The Node Name

connects this

Map Descriptor

to a Node which

in turn connects

the Map

Descriptor to a

port.

Scan_Interval,

Length

Address

Node_Name

Write to PLC Table element number 20 to

29 inclusive (10 elements)

Data_Array_Offset, Function,

element of the

st

RDBC = read block

continuous. The driver

will read data from the

PLC continuously.

Location in the Data

element of data will be

stored. The arrays are

Array where the first

Data_Array_Name,

zero referenced so an

4.4.4. Map Descriptor Example 1 – Simple Read

Map Descriptor names

may be used in driver

error messages. It is not

essential, but it is useful

Page 12 of 29FS-8700-66_GE-SNP Manual Page 12 of 29

This example provides a Map Descriptor to read 10 bytes of Discrete Input states, starting at the very first Discrete Input. The data is

stored in a Data Array called DA_DI and the first input is stored at location 100 in the array (101

Map_Descriptor_Name,

Read D1, DA_D1, 100, RDBC, PLC-1, 1, 10, 2.0, %1

seconds

array.

offset of 100 indicates

the 101

4.4.5. Map Descriptor Example 2 – Simple Write

The name of the Data Array

in which the driver will store

the data. The name must

correspond to a Data Array

to use unique names.

defined in the Data Array

This example writes data from the FieldServer Data Array called DA_AO to the PLC identified as NODE1. The write is repeated

Data_Array_Offset, Function,

Data_Array_Name,

Write continuously

Map_Descriptor_Name,

Write_AO, DA_AO, 0, WRBC, Node1, 20, 10, 5.0, %AQ

every 5 seconds. Ten word values are written to the PLC’s %AQ Data Table starting at location 20.

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The format parameter tells the driver to override the default

data type and read bits specifically. In this case the bits

are stored in the Data Array in two separate elements at

DA_T[100] and DA_T[101]

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4.4.6. Map Descriptor Example 3 – Handling Bits

Page 13 of 29FS-8700-66_GE-SNP Manual Page 13 of 29

This example writes data from the FieldServer Data Array called DA_AO to the PLC identified as NODE1. The write is repeated

Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Node_Name, Address, Length, Scan_Interval, Data_Type, Format

Read_DI,, DA_T, 100, RDBC, PLC-1, 8, 2, 2.0, %T, Bit

every 5 seconds. Ten word values are written to the PLC’s %AQ Data Table starting at location 20.

Page 14 of 29FS-8700-66_GE-SNP Manual Page 14 of 29

5. Configuring the FieldServer as a GE_SNP Server

For a detailed discussion on FieldServer configuration, please refer to the FieldServer
Configuration Manual. The information that follows describes how to expand upon the factory
defaults provided in the configuration files included with the FieldServer (See “.csv” files
provided with the FieldServer).

This section documents and describes the parameters necessary for configuring the FieldServer
to communicate with a GE_SNP Client.

The configuration file tells the FieldServer about its interfaces, and the routing of data required.
In order to enable the FieldServer for GE_SNP communications, the driver independent
FieldServer buffers need to be declared in the “Data Arrays” section, the FieldServer virtual
Node(s) needs to be declared in the “Server Side Nodes” section, and the data to be provided to
the Clients needs to be mapped in the “Server Side Map Descriptors” section. Details on how to
do this can be found below.

Note that in the tables, * indicates an optional parameter, with the bold legal value being the
default.

5.1. Server Side Connection Descriptors

Section Title

Connections

Column Title Function Legal Values

Port

Protocol

Baud* Specify baud rate

Parity* Specify parity

Data_Bits*

Stop_Bits*
Handshaking* Specify hardware handshaking

Poll Delay Time between internal polls.

Example

// Server Side Connections

Connections
Port, Protocol, Baud, Parity, Handshaking
P1, SNP, 19200, Odd, None

Specify which port the device is
connected to the FieldServer

P1-P8, R1-R23

Specify protocol used SNP

110 – 115200, standard
baud rates only
Even, Odd, None, Mark,
Space

Specify data bits

Specify stop bits

7, 8

1

RTS, RTS/CTS, None
0-3200s, 1s

3

Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction

manual for details of the ports available on specific hardware.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 15 of 29FS-8700-66_GE-SNP Manual Page 15 of 29

5.2. Server Side Node Descriptors

Section Title

Nodes

Column Title Function Legal Values

The Node name is used
differently in a Server Node
Provide name for Node. The
driver uses the Node name to

Node_Name

establish a connection with the
Server if the Node_ID is non­zero.

See Section 6.3 for additional
information.
The parameter is used to

Node_ID

control how the driver logs onto
the PLC. Read the notes above
(Node_Name)

Protocol Specify protocol used SNP.

In a number of FieldServer
configurations it is common to
omit the port when defining a
Server Node this cannot be

Server_Hold_Timeout*

done with the SNP protocol
unless the FieldServer is to be
used to emulate only one Node
and is not polling any other
SNP devices.

Example

// Server Side Nodes

Nodes
Node_Name, Node_ID, Protocol, Port
PLC 1, 1, SNP, P8

Up to 32 alphanumeric
characters

0,1

P1-P8, R1-R24

4

Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction

manual for details of the ports available on specific hardware.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 16 of 29FS-8700-66_GE-SNP Manual Page 16 of 29

5.3. Server Side Map Descriptors

5.3.1. FieldServer Specific Map Descriptor Parameters

Column Title Function Legal Values

Map_Descriptor_Name Name of this Map Descriptor

Data_Array_Name

Data_Array_Offset Starting location in Data Array

Function

Name of Data Array where data
is to be stored in the FieldServer

Function of Server Map
Descriptor

Up to 32 alphanumeric
characters
One of the Data Array names
from “Data Array” section above
0 to maximum specified in “Data
Array” section above

Server

5.3.2. Driver Specific Map Descriptor Parameters

Column Title Function Legal Values

One of the Node names
specified in “Client Node
Descriptor” above
Discrete Inputs (%I)
Discrete Outputs (%Q)
Discrete Temporaries (%T)
Discrete Internals (%M)
Genius Global Data (%G)
Analog Inputs (%AI)
Analog Outputs (%AQ)
Registers (%R)
%SA Discrete
%SB Discrete
%SC Discrete
%S Discrete (%S)

1 - 1000

1 , 2 , 3
Positive whole numbers

N/A

Node_Name

Data_Type

Length

Address

Format

Name of Node to fetch data
from

Data type

Use one of the Data Types
specified in brackets.

Length of Map Descriptor

Ensure that the length does
not exceed the table length in
the PLC.
Starting address of read block
/ write block

The 1st element of each Data
type Table is referred to as
address one.

Has no meaning on the Server
as the driver responds based
on the nature of the request

If the Client requests byte data
then the one byte is obtained
from each array element. If the
Client requests bits then one
bit state is obtained from each
array element.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

Page 17 of 29FS-8700-66_GE-SNP Manual Page 17 of 29

5.3.3. Timing Parameters

Column Title Function Legal

Values

Scada_Hold_Timeout

Specifies time Server side waits before responding to
Client that Node is offline on FieldServer Client side.

>1.0s

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

This Map Descriptor will

be used to process

Client read/writes of

Register (%R) data.

This Map Descriptor can be

used to respond to a poll

that reads and writes to

addresses 1 to 1000. If a

poll attempts to read data at

address 1001, then if no

other Map Descriptor covers

that address space, a “no

datas” response will be sent.

This is a Server. It

responds to polls but

does no active work

itself.

location)

st

in the array. If Client

reads %R15 then driver

responds with data from

to offset 0 (1

Address1 corresponds

element 14 of the array.

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5.3.4. Map Descriptor Example.

If the Client is reading

then response data will

be obtained from this

table. If the Client is

writing, incoming data

will be stored in this

Page 18 of 29FS-8700-66_GE-SNP Manual Page 18 of 29

Map_Descriptor_Name, Data_Array_Name, Data_Array_Offset, Function, Node_Name, Address, Length, Data_Type

Server-R-Data, TABLE_R, 0, Passive, PLC-1, 1, 1000, %R

array

Page 19 of 29FS-8700-66_GE-SNP Manual Page 19 of 29

Appendix A. Troubleshooting Tips

• Every 2nd message Times Out A possible cause is that the poll frequency is so low that
the time between polls is greater than the Max Link Idle Time (of the PLC). If the time is
exceeded the connection is closed. Thus when the next poll is received by the PLC it
ignores it and hence it times out in the FieldServer. After timing out, the driver re-establishes
the connection for the next poll.

• Very slow Comms Rate A timer known as the T1 timer is the minimum time that must pass
before a response to a message can be sent. Both ends of a SNP connection have their
own T1 timer (hard coded in the driver). When a connection is made the timers are
exchanged and the larger of the two is used. The drivers T1 timer is set to a very small
number. SNP message #6 indicates the size of the T1 timer. You may need to configure the
PLC to improve communications.

• Multidrop RS-485 networks. SNP protocol specifies that their may only be one master
on a network at a time. When using nameless Nodes (Node_id=0) there may be one and
only one PLC on the connection.

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Page 20 of 29FS-8700-66_GE-SNP Manual Page 20 of 29

request. Mjr=%x(h) Min=%x(h)

Appendix B. Error Messages

Message Explanation

SNP:#1 FYI. The MapDesc called
<%s> is too short.
SNP:#2 FYI. You could have
used a MapDesc called <%s> to
expose diagnostic info.

SNP:#3 FYI. SNP device requires
inter msg timer < timeout.
Nid=<%s>.

SNP:#4 Error. Cant emulate
Node=<%s>

SNP:#5 Err. Total bytes
expected/rcvd=%d/%d

SNP:#6 FYI. T1 timer set to
<%ld> mSec.

SNP:#7 FYI. T1 timer reset to
<%ld> mSec.
SNP:8 FYI. Subsequent connect
response ignored. NName=<%s>

SNP:9 Err. Device declined

Possible Offending Poll =<%s>
addr=%d length=%d

SNP:10 Err. Wrong msg
type=%d(h) mbox=%x(h)

The length of the Map Descriptor defined to expose driver
statistics must be at least 660.5
You may safely ignore this message. Read Appendix B.1
for information on how to expose the driver’s
communication statistics using a Data Array.
The driver is required to use the larger of its own or the
PLC’s T1 (Inter message) timer. This message is
produced when the PLC returns a T1 timer that is larger
than the driver’s timeout. Using this timer will mean that
every message will timeout. Increase the timeout for the
Node, connection or Map Descriptor as appropriate.5
A connection request has been received for the Node
named in the error message but this Node has not been
defined in the CSV file. The connection has not been
established.5
This could result from a corrupted message or it may
indicate an unexpected/unsupported aspect of the SNP
protocol. If the message occurs frequently, take a log and
report the error to FieldServer.
This message requires no action. It reports the T1 timer
value selected by the slave in milliseconds. If the value is
large then this will slow the communications rate and you
may wish to reconfigure the slave.
This is the FieldServer slave reporting its T1 timer after a
Client has established a connection No action is required.
No action is required. A Client has attempted to re­establish a connection that is already open.
This message uses two lines of the error log. It is printed
when a slave declines a request. The major and minor
faults are reported. These numbers are printed in
hexadecimal. See Appendix C.3 for further details. The
message reports the Map Descriptor which generated the
rejected poll, the data type, the address and the number of
elements being requested. Often this message will be the
result of a poll that requests data past the end of a PLC
data table or when the length is based on a bit count but
the poll actually requests bytes.5
This message is reported when the driver receives an
unexpected SNP message. Record this information, take
a log and report the error to FieldServer.

5

Edit the CSV, correct the problem and reset the FieldServer

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Page 21 of 29FS-8700-66_GE-SNP Manual Page 21 of 29

Message Explanation

The length of some messages is variable and is
dependent on settings or the particular implementation of
the SNP. Normally this driver adjusts to use the largest

SNP:11 Err. Max Tbuf Len.
FieldServer cant go bigger than
%d bytes
Possible Offending Poll =<%s>
addr=%d length=%d

size required by a Client or slave response but this
message indicates that the driver’s maximum had been
reached. The data has been discarded so it is important
that the situation be remedied. The data type, address and
the number of elements being requested are reported.
Two possible solutions exist.
Change the Client’s communications configuration and
reduce the size of the text buffer length to 4096 bytes.
Create two Map Descriptors that each read half the data.

SNP:12 FYI. Max Tbuf Len.
FieldServer != Device. Changed
FieldServer to %d bytes

SNP:13 Err. Wrong msg
type=%d(h) mbox=%x(h)

This message requires no response. It indicates that the
slave requires a longer text buffer than the driver’s default.
The driver has adjusted its buffer to the new length
indicated.
The driver has received an unexpected reply in response
to a poll. Make a log, record the values reported in this
message and contact FieldServer for support.
The driver has been polled by a Client and it has received

an unexpected message. If the error occurs repeatedly
SNP:#14 Error. Attach Response.
Unexpected !

then make a log, record the values reported in this

message and contact FieldServer for support. There are a

few variations of this message but they all indicate the

same problem.
SNP:#15 FYI. Node Station ­forcing to 0
SNP:#16 Err. Addresses start at

1. MapDesc=<%s>

The Node_ID has not been defined for a SNP Node. Read

the notes in Appendix B.1 and in sections 4.3 and 5.2. 6

GE devices number the elements of data tables starting at

element 1.6
SNP:#17 Err. MapDesc=<%s>
has bad data type.
SNP:#18 Err. MapDesc=<%s>

Refer to section 4.4.2 for a list of valid data types.6

has bad data type.
SNP:#19 Err. Mapdesc=<%s>
has invalid length.
SNP:#20 Err. do diagnostic x
SNP:#21 Err. do diagnostic x

SNP:#22 Err. do diagnostic x

SNP:#23 Err. Illegal Node_ID
[%d] - Set to 1

A Map Descriptor must have a length. The minimum

length is “1”. 6

If you see this error, report it to FieldServer tech support.

The message is produced when a QA diagnostic is

produced and should only ever be seen during testing by

FieldServer Inc.

Legal Node_ID’s are 0-65535.6

The CPU Id is a max 10 characters including the

GE_SNP:#24 FYI. Parse Error:
Attach: CPU ID is not Null
terminated.

terminating Null character. The driver has found one that

isn’t correctly formatted. This error may be ignored. It will

not affect operation of the driver. It does mean the driver

cannot store the name of the connected device in the stats

array.

6

Edit the CSV, correct the problem and reset the FieldServer

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Page 22 of 29FS-8700-66_GE-SNP Manual Page 22 of 29

This is 10 bytes long. The numbers placed

here correspond to the ASCII characters of

ue of the T1 timer is

reported here. The driver uses the larger of

See

Appendix B.1. Driver Stats

The statistics recorded by the GE-SNP Serial Driver are slightly different from the way that
FieldServer driver normally records statistics. This difference arises from the fact that this
driver is not a simple poll response driver. Bear in mind that a single poll can generate a
large number of response fragments.

Fragment Ack/nack messages are NOT counted as messages but the bytes sent/rcvd are
counted.
Connection messages are counted as messages and the bytes sent/rcvd are counted.

This driver can expose these and additional statistics by writing data to a Data Array.

A special Map Descriptor is required. The driver recognizes the Map Descriptor by its name
which must be "SNP-stats”.

Example: Configuration of this special Map Descriptor

Nodes
Node_Name, Protocol
Null_Node, SNP

Data_Arrays
Data_Array_Name, Data_Format, Data_Array_Length
SNP_STATS , UINT32 , 660

Map_Descriptors
Map_Descriptor_Name, Data_Array_Name, Node_Name, Length
snp-stats , SNP_STATS , Null_Node , 660

When the driver sees this Map Descriptor it uses the Data Array SNP_STATS (in this
example) to store driver specific statistics. Only one of these Map Descriptors may be
specified (per tier) per FieldServer.

The driver stores the following stats for each port.. The offset into the Data Array can be
found by multiplying the port number by 60

No Message Description

0 GE_STAT_CPU_ID

11 GE_STAT_T1_TIMER

12 GE_STAT_MBOX_NAK_MAJOR
13 GE_STAT_MBOX_NAK_MINOR
14 GE_STAT_MBOX_NAK_CNT Mailbox Nak error Count
15 GE_STAT_MBOX_PROG_NUM
16 GE_STAT_MBOX_SWEEP

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the responding Node's name.
The current val

its own and the slave T1 Timer.
Most recent Mailbox Nak error code.

additional table below

Most recent Piggyback info

Page 23 of 29FS-8700-66_GE-SNP Manual Page 23 of 29

If a poll for a SNP Node is received and

there are no Nodes defined or there is no

Counts the number of time a connection

of times the driver

responds to connection attempts when

Counts the number of connection attempts

Counts the number of connection and poll

nt by the Client (whole

Counts the number of simple ack/nak’s sent

by Client. These ack/nak’s indicate

messages if formatted correctly, however

the device can not necessarily respond to

Byte count includes ack/nak's sent and all

DRV_DLL_SERVER_SENDS_ACKNAK

Counts ack/nak’s, and all message

Counts message fragments and ack/nak’s

t excludes Client

Count of timeouts caused by no response

Count of the number of times that the DLL

The error code from the most recent DLL

GE_STAT_DRV_ACT_NODE_OFFLINE_R

n

responding to a poll. The polled Node is

Corresponds to slave driver actions in

responding to a poll. There is no Map

Descriptor that can be used to process the

No Message Description

17 GE_STAT_MBOX_PLC_STAT
18 GE_STAT_MBOX_PRIV_LVL

19 GE_STAT_NO_NODES

matching Node.

20 GE_STAT_CONNECT_ATTEMPT

attempt is made
Counts the number

21 GE_STAT_CONNECT_RESPONSE

acting as a Server

22 GE_STAT_CONNECT_NO_RESPONSE

23 DRV_DLL_CLIENT_SENDS_MSG

that timed out.

messages se
messages only)

24 DRV_DLL_CLIENT_SENDS_ACKNAK

the request.

25 DRV_DLL_CLIENT_SENDS_BYTES

fragments and connection
26 DRV_DLL_SERVER_SENDS_MSG
27

Same as for Client
28 DRV_DLL_SERVER_SENDS_BYTES

29 DRV_DLL_CLIENT_RCVS_MSG

fragments excluding attach responses
30 DRV_DLL_CLIENT_RCVS_BYTES Byte count from above messages

31 DRV_DLL_SERVER_RCVS_MSG

rcvd from Client bu

responses to Server fragments
32 DRV_DLL_SERVER_RCVS_BYTES Byte count for above messages

33 DRV_DLL_TIMEOUT

34 DRV_DLL_ERROR

35 DRV_DLL_ERROR_CODE

or ic_timeout at the DLL layer

layer went into an error state.

error is stored here.

Corresponds to slave driver actions i
36

offline.

37 GE_STAT_DRV_ACT_NO_MAPDESC_R

poll from the Client.

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Page 24 of 29FS-8700-66_GE-SNP Manual Page 24 of 29

Corresponds to slave driver actions in

There is no data

Corresponds to slave driver actions in

responding to a poll. This should never

ve been

The slave cannot respond to a poll for one

The Server has responded to a poll

alid because the

A message is invalid because the message

A message is invalid because it begins with

A message is invalid because it is

unexpected in its current context or some

Counts the number of read/write message

the number of times that an IC

Counts the number of times a message

was ignored. A message will be printed to

Counts the number of times that the slave

Counts the number of times the DLL layer's

buffer was too full to process additional

No Message Description

38 GE_STAT_DRV_ACT_NO_DATA_R

39 GE_STAT_DRV_ACT_NO_NODE_R

40 GE_STAT_DRV_ACT_NAK_R

41 GE_STAT_DRV_ACT_NORMAL_R

42 GE_STAT_CD_UPD_CHECK

43 GE_STAT_CD_UPD_FUNCTION

44 GE_STAT_CD_UPD_NO_START

45 GE_STAT_CD_UPD_PROTO

46 GE_STAT_CLIENT_SENDS_FRAG

47 GE_STAT_CD_UPD_IC_TIMEOUT

responding to a poll.

available.

happen as a connection would ha

refused.

of the reasons above.

normally

A message is inv

checksum failed.

type is not known.

the wrong codes.

other reason.

fragments sent by the Client.

Counts

timeout error occurred at the DLL layer

48 GE_STAT_CD_UPD_MSG_IGNORED

49 GE_STAT_CD_UPD_NAK

50 GE_STAT_CD_UPD_STREAMING

the error log with the reason.

received a short nak from the Client

incoming data.

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Page 25 of 29FS-8700-66_GE-SNP Manual Page 25 of 29

Appendix C. Advanced Topics

Appendix C.1. SNP Node Names

The following notes describe how the Node name is used when the FieldServer is acting as
a Server.

When a Client attempts to establish a connection it may do so by sending the name of the
Node it wishes to connect to or by sending a Null Node name.

If the Client sends a Null Node name then the FieldServer will connect if any SNP Nodes
have been defined for the same port as the Client using the Null name. In such a case the
Node must be connected to a port (This is not always common with FieldServer Server
configurations).

Example: Client uses Null name connection. In this case Node must be connected to the
Client’s port; the Node name is ignored and only one SNP Node per port.

Ports
Port, baud
P1 , ….

Nodes
Node_Name, Port
Node1, P1

If the Client uses the Node name during a connection attempt then the FieldServer uses
the name to find a matching Node. The name must be an exact match. If a match is found
then the connection can be established. In this case the Node does not have to be tied to
a particular port and thus one Node could respond to different Clients polling it on different
ports. If this method is used and the Node is tied to a port then the Client must poll on the
same port.

Example: Client uses a specific name to connect. In this case provided there is a Node
with a matching name the connection will be made

Ports
Port, baud ….
P1, ….

Nodes
Node_Name, Protocol
Node1, SNP

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Page 26 of 29FS-8700-66_GE-SNP Manual Page 26 of 29

Appendix C.2. Scaling

Scaling was added in version 1.02a and is not supported for earlier versions.

Scaling is applied by the driver when bytes and registers are stored.

When bit data is transferred in bit format than scaling is not applied. When bit data is
transferred using bye format’s then scaling may be applied.

Scaling is applied using the FieldServer’s standard Map Descriptor parameters.

Data_Array_Low_Scale,
Data_Array_High_Scale,
Device_Low_Scale,
Device_High_Scale

Appendix C.3. Server Response NAK, Major and Minor Error Codes

From version 1.02c the when the Server responds with a MailBox Nak it now allocates
different Major and Minor error codes to differentiate the NAK reasons.

0x05 0xbe No Such Node The request Node is not known by the Server.
0x05 0xbd No Data The Data age is greater than the CACHE_AGE setting.
0x05 0xbc Other Problems Eg. No Server MD’s defined for requested data.

Major Error Status Codes

Error Status Description

01h Illegal Service Request: Either not defined or not supported.

02h Insufficient Privilege:

04h Protocol Sequence Error: The CPU has received a message that is out of order.

05h Service Request Error:

06h Illegal Mailbox Type:

07h The PLC CPU's Service Request
Queue is full. The master should retry
later.

Minor Error Status Codes

Decimal Hex Description

-1 0FF Service request has been aborted.

-2 0FE No privilege for attempted operation.

-3 0FD Unable to perform auto configuration.

-4 0FC I/O configuration is invalid.

-5 0FB Cannot clear I/O configuration.

-6 0FA Cannot replace I/O module.

-7 0F9 Task address out of range.

-8 0F8 Invalid task name referenced.

-9 0F7 Required to log in to a task for service.

Minor status field contains the privilege level required
for the service request

Minor status field contains the request specific error
code. See table of Minor Error Status Codes below.
Service request mailbox type is either undefined or
unexpected.

It is recommended that the master wait a minimum of
10 ms before sending another service

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Decimal Hex Description

-10 0F6 Invalid sweep state to set.

-11 0F5 Invalid password.

-12 0F4 Invalid input parameter in request.

-13 0F3 I/O configuration mismatch.

-14 0F2 Invalid program cannot log in.

-15 0F1 Request only valid from programmer.

-16 0F0 Request only valid in stop mode.

-17 0EF Programmer is already attached.

-18 0EE Could not return block sizes.

-19 0ED VMEbus error encountered.

-20 0EC Task unable to be created.

-21 0EB Task unable to be deleted.

-22 0EA Not logged in to process service request.

-23 0E9 Segment selector not valid in context.

-24 0E8 No user memory is available to allocate.

-25 0E7 Configuration is not valid.

-26 0E6 CPU model number does not match.

-27 0E5 DOS file area not formatted.

-28 0E4 Segment for this selector does not exist.

-29 0E3 CPU revision number does not match.

-30 0E2 IOS could not delete configuration or bad type.

-31 0E1 No I/O configuration to read or delete.

-32 0E0 Service in process cannot login.

-33 0DF Invalid Datagram connection address.

-34 0DE Size of Datagram connection invalid.

-35 0DD Unable to locate given connection ID.

-36 0DC Unable to find connection address.

-37 0DB Invalid segment selector in Datagram.

-38 0DA Null pointer to data in segment selector.

-39 0D9 Transfer type invalid for this selector.

-40 0D8 Point length not allowed.

-41 0D7 Invalid Datagram type specified.

-42 0D6 Datagram connection boundary exceeded.

-43 0D5 Invalid block name specified in Datagram.

-44 0D4 Mismatch of configuration checksum.

-45 0D3 User Program Module (UPM) read or write exceeded block end.

-46 0D2 Invalid write mode parameter.

-47 0D1 Packet size or total program size does not match input.

-48 0D0 One or more PLC modules configured have unsupported revision.
49 0CF Specified device is unavailable in the system (not present).

-50 0CE Specified device has insufficient memory to handle request.

-51 0CD Attempt was made to read a device but no data has been stored on it.

-52 0CC Data stored on device has been corrupted and is no longer reliable.

-53 0CB A comm or write verify error occurred during save or restore.

-54 0CA Device is write protected.

-55 0C9 Login using non-zero buffer size required for block commands.

-56 0C8 Password(s) already enabled and cannot be forced inactive.

-57 0C7 Passwords are set to inactive and cannot be enabled or disabled.

-58 0C6 Control Program (CP) tasks exist but requestor not logged into main CP.

-59 0C5 No task-level Rack/Slot configuration to read or delete.

-60 0C4 Verify with FA Card or EEPROM failed.

-61 0C3 Text length does not match traffic type.

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Decimal Hex Description

-62 0C2 The OEM key is NULL (inactive).

-63 0C1 Invalid block state transition.

-64 0C0 Bad OMF record checksum in store.

-65 0BF Illegal OMF record type/data contents.

-66 0B Bad Block Type given in Load/Store.

-67 0BD Block Set (subblock name) not found.

-68 0BC Block Type (e.g., data) not found.

-69 0B Maximum length of a partial store exceeded.

-70 0B Block Set already exists, cannot create.

-71 0B9 Executable flag in TYPDEF record not set.

-72 0B8 Size of the Segment Selector Table in TYPDEF record is not correct.

-73 0B7 Segment length in Verify not equal to the segment length of block in the PLC.

-74 0B6 Cyclic Redundancy Check (CRC) checksum comparison in Verify failed.

-75 0B5 Additive checksum comparison in Verify failed.

-76 0B4 Attempt to alter interrupt list in MAIN DECL BLOCK during RUN MODE.

-77 0B3 Length limit exceeded; includes read past end of transferred data, writes past

ofprogram block.

-78 0B2 Program block already exists and cannot be replaced.

Minor Error Status Codes: Program Load and Store Requests

Decimal, Hex, Description

80 50

81 51

85 55

86 56

87 57

88 58

Problem with sending mail to the slave Service Request task. (Series 90-70 PLC
CPUs only).
Problem with getting mail from the slave Service Request task. (Series 90-70
PLC CPUs only).
Slave SNP task timed out before receiving SRP response. (Series 90-70 PLC
CPUs only).
Slave SNP task could not find the requested Datagram connection. (Series 90-70
PLC CPUs only).
Slave SNP task encountered an error in trying to write the Datagram. (Series 90­70 PLC CPUs only).
Slave SNP task encountered an error in trying to update the Datagram. Series
90-70 PLC CPUs only).

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