2 load cells, 3 serial communications, Load cells – Rice Lake 820i Programmable Indicator/Controller - Installation Manual User Manual

Page 11: Serial communications

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Installation

7

2.3.2

Load Cells

To attach cable from a load cell or junction box to the

820i

, route the cable through the cord grip and ground

the shield wire as described in Section 2.3.1 on

page

6.

Next, remove load cell connector J7 or J8 from CPU

board. Wire the load cell cable from the load cell or

junction box to the connector as shown in Table

2-1.

J7

LOAD CELL

CONNECTOR

J8

LOAD CELL

CONNECTOR

+SIG

–SIG

+SENS

–SENS

+EXC

–EXC

+SIG

–SIG

+SENS

–SENS

+EXC

–EXC

Figure 2-2. Load Cell Connectors

If using 6-wire load cell cable (with sense wires),

remove jumpers JP1 and JP2 before reinstalling

connector J7. For 4-wire installation, leave jumpers

JP1 and JP2 on. For 6-wire load cell connections on

dual-channel A/D cards, remove jumpers JP3 and JP4

for connections to J8.
When connections are complete, reinstall load cell

connector on the CPU board header and use two cable

ties to secure the load cell cable to the inside of the

enclosure.

Table 2-1. Load Cell Connector Pin Assignments

J7 or J8

Connector Pin

Function

1

+SIG

2

–SIG

3

+SENSE

4

–SENSE

5

+EXC

6

–EXC

For 6-wire load cell connections to connector J7, remove

jumpers JP1 and JP2.

For 6-wire load cell connections to connector J8 (dual A/D
boards), remove jumpers JP3 and JP4.

2.3.3

Serial Communications

Communications ports on the

820i

CPU board support

PS/2-type remote keyboard, full duplex RS-232, 20

mA output, or RS-485 communications at up to

115200 bps. Optional communications cards support

USB, Ethernet, and fiber-optic connections to the

820i

.

To attach serial communications cables, route the

cable through the cord grip and ground the shield wire

as described in Section 2.3.1 on page 6. Remove the

serial connector from the CPU board and wire to the

connector. Once cables are attached, plug the

connector into the header on the board. Use cable ties

to secure serial cables to the inside of the enclosure.
Table 2-2 shows the pin assignments for Ports 1, 2,

and 4. Port 1 supports remote keyboard attachment of

PS/2-type personal computer keyboards (see

Section 10.9 on page 99 for information about the

PS/2 keyboard interface.)

Table 2-2. Serial Port Pin Assignments

Connector

Pin

Signal

Port

J9

1

CLK

1

2

+5V

3

GND

4

DATA

J10

1

GND

2

2

RS-232 RxD

3

RS-232 TxD

4

RS-232 RTS

5

RS-232 CTS

6

GND

J11

1

GND

4

2

N/C

3

N/C

4

RS-485 A

5

RS-485 B

6

+20mA OUT

7

–20mA OUT

8

GND

9

RS-232 RxD

10

RS-232 TxD

Serial ports are configured using the SERIAL menu.

See Section 3.2.2 on page 30 for configuration

information.
An optional dual-channel serial communications

expansion card, PN 67604, is also available. The

serial expansion card provides two additional serial

ports, assigned as port numbers 7 and 8. One port on

the serial expansion card supports four-wire RS-485

communications. Both ports on the expansion card

can support RS-232 or 20mA connections.

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