Flowserve DDC-100 Modbus Direct-to-Host - Manual (Page 13)

20 DDC-100 Direct-to-Host Programming Guide FCD LMAIM4019-00 FCD LMAIM4019-00 DDC-100 Direct-to-Host Programming Guide 21
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 0 Yes Yes Yes Yes
Open 256 Yes Yes Yes Do Not Use
Stop 512 Yes Yes Yes Do Not Use
Close 768 Yes Yes Yes Do Not Use
Start Network ESD 1280 Yes Yes Yes Do Not Use
Stop Network ESD 1536 Yes Yes Yes Do Not Use
Engage Relay #1 2304 Yes (AS-1) Do Not Use Do Not Use Yes, K21
Engage Relay #2 2560 Yes (AS-2) Do Not Use Do Not Use Yes, K12
Engage Relay #3 2816 Yes (AS-3) Yes Yes Yes
Engage Relay #4 3072 Yes (AS-4) Do Not Use Yes Yes
Engage Relay #5 3328 Yes (AR-1) Do Not Use Yes Yes
Engage Relay #6 3584 Yes (AR-2) Yes Yes Yes
Engage Relay #7 3840 Yes (AR-3) Do Not Use Do Not Use Do Not Use
Disengage Relay #1 4352 Yes (AS-1) Do Not Use Do Not Use Yes, K21
Disengage Relay #2 4608 Yes (AS-2) Do Not Use Do Not Use Yes, K12
Disengage Relay #3 4864 Yes (AS-3) Yes Yes Yes
Disengage Relay #4 5120 Yes (AS-4) Do Not Use Yes Yes
Disengage Relay #5 5376 Yes (AR-1) Do Not Use Yes Yes
Disengage Relay #6 5632 Yes (AR-2) Yes Yes Yes
Disengage Relay #7 5888 Yes (AR-3) Do Not Use Do Not Use Do Not Use
Move-To (enable) 6656 Yes Yes 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
B3 Slave (Field Unit) Address B3
Slave (Field Unit)
Address
06 Function 06 Function
00 Register Address Hi 00 Register Address Hi
001 Register Address Lo 00 Register Address Lo
01 Force Data Hi 01 Preset Data Hi
002 Force Data Lo 00 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
B3 Slave (Field Unit) Address B3
Slave (Field Unit)
Address
06 Function 06 Function
00 Register Address Hi 00 Register Address Hi
011 Register Address Lo 01 Register Address Lo
00 Force Data Hi 00 Preset Data Hi
2A2 Force Data Lo 2A 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.