Micromod Micro-DCI: 53SL5100A Single Loop Controller - Manual (Page 133)

Single Loop Process Controller Instruction Manual
Communications 125
Appendix B: Communications
B.1 Standard Communications
Two digital communication channels are provided with this instrument:
1. There is a configuration port that is an RS-232 serial interface. It is accessed via a 5 pin
mini-DIN connector located under the pull-down door on the front panel (see
Figure 3-1 ). It is
used to configure instrument parameters for selected operational characteristics. The
parameters are configured with the Hand-Held Configurer (HHC), as described in
Section 3 , or
with a customer-supplied PC executing the appropriate software.
2. There is also an RS-422/485 serial interface used to connect the instrument to a Datalink
multi-drop network. Interface connection to the Datalink network is via the rear terminal board
(TB1) of the instrument, pins 19 through 22, as shown in
Section 2 .
Information in this section applies to both the configuration port and the Datalink interface, with the follow-
ing exceptions:
1. The configuration port data rate is 9600 baud, with 8 data bits, and no parity.
2. The configuration port powers up in standard mode suitable for use with the HHC, but can be
switched to binary mode by sending the following four-character sequence:
Sent 03H 1 BH 0EH 15H
Echoed 1BH 20H 0EH 20H 15H
After echoing the 15H character, the instrument switches to binary mode and is able to
process binary communications messages from that time on. (Characters sent after the 15H
and before the 15H echo are ignored.)
3. Once the configuration port switches to binary mode, it remains in that mode as long as the
connection is maintained. The connection is maintained by sending a character at least once
every 30 seconds. If 30 seconds elapses without a character being received by the instrument
through the configuration port, the port returns to standard mode.
4. When in binary mode, the instrument responds to all messages regardless of the address to
which they are directed.
The Datalink interface requires four conductors: a transmit pair and a receive pair. The voltage levels of
each conductor pair conform to the EIA RS-422/485 standard. In accordance with this standard, the overall
Datalink network distance is limited to 4000 feet when #24 AWG twisted pair wire is used to interconnect
the nodes. Adapters are available to convert RS-422/485 to RS-232 or 20 mA current loops.
In a Datalink network, the instruments communicate as Responders to host or SUPERVISOR-PC queries.
The host or PC functions as the Interrogator and acts as the central control point for the Datalink network.
A maximum of 32 addressable instruments can be connected to a Datalink network. Using the
SUPERVISOR-PC in a Datalink network system allows a variety of services to be implemented as
described in the SUPERVISOR-PC Instruction Bulletin, IB 53SU5000.
✎ Note
Numbers used in this section that are expressed In hexadecimal
notation (base 16) are identified with an H after the number.