Flowserve MX-100 Field Unit - Manual (Page 41)

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MX/DDC-100 Field Unit Installation and Maintenance FCD LMENIM2329-01 – 03/11
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DDC Address
The network address must be entered in accordance with the Instrument Data Sheet, and care must be taken to
ensure that the same address is not used anywhere else in the same network. Select “NO” for small incremental
changes or hold it continuously in that position for larger changes until the required value is displayed. The address
may be set at any value between 001 and 250.
WARNING: c Each actuator must have a unique address.
Analog Scale
The digital values of external analog data received over the DDC network may be scaled as shown below to suit the
users preference.
Using the black control knob, select “NO” until the required scale is displayed. The scale options are as follows:
• 0-100 of span
• 0-255 of span
• 0-4095 of span
The changing of the analog scale will affect all the digital values in registers 3, 4, 6, 7, 8 and “move-to” commands.
Scaling conventions must be consistent between the field unit and host device.
Standard Digital Inputs (Register 12, Bits 08–13)
The field unit contains six digital inputs for monitoring the status of external contacts. The inputs may be powered
one of two ways:
From the MX (24 VDC) •
From the customer’s source (24 VDC or 120 VAC) •
NOTE: These digital inputs are meaningful only when DDC option is used.
The six standard digital inputs may be configured in a number of ways for monitor and/or control. (See Table 3.4 and
Table 3.5.) In any selected configuration, the inputs may be monitored via the DDC-100 network by reading the field
unit holding registers 40012 and 40013.
The presence of voltage on a terminal will indicate a “TRUE” condition. The absence of voltage will indicate a “FALSE”
condition.
Depending on configuration, the host may read the digital input to monitor field-installed devices connected to the
MX/DDC input OR may monitor the digital input to verify an actuator function in relation to a preselected condition
(ESD, Hardwire Remote Control, Inhibits).
3.3.1.3 Configuring for Position Control or “Move-To” Operation (Option)
The MX/DDC contains a default proportional band value of 15% and a deadband value of 2%. The MX/DDC may be
sent to an intermediate position by utilizing the Modbus function code 06. First issue the desired position, then issue
the “move-to” enable (see Table 2.4).
To alter the default proportional band and deadband values, the modulating position control (MPC) feature must be
enabled.
MX/DDC field units are shipped without MPC enabled, but this feature may be enabled in the field. Please contact the
Flowserve Limitorque Service Department to order the MPC feature which allows adjustments of the proportional
band and deadband values.
NOTE: If DDC option is ON, the Modutronic option must be OFF.
To alter proportional band and deadband values: (Refer to Bulletin LMENIM2306, Section: Modutronic Option)