Flowserve DDC-100 Modbus Direct-to-Host User Manual

Page 13

DDC-100 Direct-to-Host Programming Guide

FCD LMAIM4019-00

DDC-100 Direct-to-Host Programming Guide

Modbus function code 06 command values for controlling the DDC-100 Field Unit are given in Table
3.7. Each command should be issued only one time for the desired field unit control. Repeated
issuance of an acknowledged command will degrade network performance.

The normal response to the (06) command is an echo of the command.

NOTE:

1) Only use values listed in table 3.7 For field unit register 40001.

2) Field Unit Register 40002 should only be used for “move-to” position input.

3) The Host MUST issue “move-to” commands in the proper sequence. Failure to issue this

two-step command in the correct sequence will result in the field unit waiting for the proper
command sequence execution before performing the “move-to” function.

4) The “move-to” command should only be used with field units that include the position control

option.

5) Do not write to Field Unit Registers 5-16.

Table 3.7 – Modbus 06 Command and Field Unit Holding Register 40001

Host Commands to

Field Unit Register 1

Value

(dec.)

MX-DDC

UEC-3-DDC

DDC-100

Clamshell

I/O Module

Null Command

Yes

Open

256

Yes

Do Not Use

Stop

512

Yes

Do Not Use

768

Yes

Do Not Use

Start Network ESD

1280

Yes

Do Not Use

Stop Network ESD

1536

Yes

Do Not Use

Engage Relay #1

2304

Yes (AS-1)

Do Not Use

Yes, K21

Engage Relay #2

2560

Yes (AS-2)

Do Not Use

Yes, K12

Engage Relay #3

2816

Yes (AS-3)

Yes

Engage Relay #4

3072

Yes (AS-4)

Do Not Use

Yes

Engage Relay #5

3328

Yes (AR-1)

Do Not Use

Yes

Engage Relay #6

3584

Yes (AR-2)

Yes

Engage Relay #7

3840

Yes (AR-3)

Do Not Use

Disengage Relay #1

4352

Yes (AS-1)

Do Not Use

Yes, K21

Disengage Relay #2

4608

Yes (AS-2)

Do Not Use

Yes, K12

Disengage Relay #3

4864

Yes (AS-3)

Yes

Disengage Relay #4

5120

Yes (AS-4)

Do Not Use

Yes

Disengage Relay #5

5376

Yes (AR-1)

Do Not Use

Yes

Disengage Relay #6

5632

Yes (AR-2)

Yes

Disengage Relay #7

5888

Yes (AR-3)

Do Not Use

Move-To (enable)

6656

Yes

Do Not Use

Note 1: Engage and disengage Relay #1 control physical Relay K2.
Note 2: Engage and disengage Relay #2 control physical Relay K1.
Do Not Use–This command is not intended for use in this configuration.
Other registers may also be preset to control or change other functions but care must always be taken to

properly change these values. An improper value written to a register can cause undesirable actions from the

DDC-100 Field Unit.
NOTE: Null Command–The field unit takes no action when this command is received. This command is

typically used by a Host to reset the Host output register when required.

Example of Field Unit Command
Write the command to open an actuator (actuator open) to field unit number 179. This corre-
sponds to writing the value 256 into field unit register 40001.

Query: B306000001009388

Response: B306000001009388

Message Breakdown

Query

Response

Slave (Field Unit) Address

Slave (Field Unit)

Address

Function

001

Force Data Hi

Preset Data Hi

002

Force Data Lo

Preset Data Lo

9388

Error Check (CRC)

9388

Error Check (CRC)

Note 1: 0000h equals Register Address 40001 (field unit register 1, command register).
Note 2: 0100h requests the register to be preset with 256 Decimal (engage open contactor).

Example of “Move-To” Command
Move an actuator at address 179 to 42% of open by first writing the value of 42 to the field unit
40002 register. After receiving a response from the field unit, write the value of 6656 to the field
unit 40001 register. The actuator will then move to a position of 42% of open.

First Command
Query: B3060001002A4207

Response: B3060001002A4207

First Command Message Breakdown

Query

Response

Slave (Field Unit) Address

Slave (Field Unit)

Address

Function

011

Force Data Hi

Preset Data Hi

2A2

Force Data Lo

Preset Data Lo

4207

Error Check (CRC)

4207

Error Check (CRC)

Note 1: 001h equals Register Address 40002 (field unit register 2, argument register).
Note 2: 002Ah equals 42.